Microbiology - First Aid Flashcards
(796 cards)
1
Q
Bacterial Appendages:
- made of proteins
- motility
A
Flagellum
2
Q
Bacterial Appendages:
- made of glycoproteins
- mediate adherence of bacteria to cell surface
- sex pilus forms during conjugation
A
Pilus/Fimbria
3
Q
Bacterial Structures:
- has a keratin-like coat
- made of dipicolinic acid, peptidoglycan and DNA
- gram ⊕ only
- resists dehydration, heat, and chemicals
A
Spore
4
Q
Bacterial Cell Envelope:
- has an organized, discrete polysaccharide layer (except poly-d-glutamate on B anthracis)
- protects against phagocytosis
A
Capsule
5
Q
Bacterial Cell Envelope:
- loose network of polysaccharides
- mediates adherence to surfaces, especially foreign surfaces (eg. indwelling catheters)
A
Glycocalyx
6
Q
Bacterial Cell Envelope:
- Outer Leaflet: contains endotoxin (LPS/LOS)
- Embedded Proteins: porins and other outer membrane proteins (OMPs)
- Inner Leaflet: phospholipids
- gram ⊝ only
- Endotoxin: lipid A induces TNF and IL-1, antigenic O polysaccharide component
- most OMPs are antigenic
- Porins: transport across outer membrane
A
Outer Membrane
7
Q
Bacterial Cell Envelope:
- space between cytoplasmic membrane and outer membrane in gram ⊝ bacteria (peptidoglycan in middle)
- accumulates components exiting gram ⊝ cells, including hydrolytic enzymes (eg. β-lactamases)
A
Periplasm
8
Q
Bacterial Cell Envelope:
- peptidoglycan is a sugar backbone with peptide side chains cross-linked by transpeptidase
- net-like structure gives rigid support
- protects against osmotic pressure damage
A
Cell Wall
9
Q
Bacterial Cell Envelope:
- phospholipid bilayer sac with embedded proteins (eg. penicillin-binding proteins [PBPs]) and other enzymes
- lipoteichoic acids (gram ⊕ only) extend from membrane to exterior
- site of oxidative and transport enzymes
- PBPs involved in cell wall synthesis
- lipoteichoic acids induce TNF-α and IL-1
A
Cytoplasmic Membrane
10
Q
Bacterial Cell Envelope
A
11
Q
Bacterial Taxonomy:
spherical
A
Coccus
12
Q
Bacterial Taxonomy:
rod
A
Bacillus
13
Q
Bacterial Taxonomy:
no cell wall
A
Pleomorphic
14
Q
Bacterial Taxonomy:
spiral
A
Spirochete
15
Q
Bacterial Taxonomy:
Gram ⊕ Cocci
A
- Staphylococcus (clusters)
- Streptococcus (chains or pairs)
- Enterococcus (pairs or short chains)
16
Q
Bacterial Taxonomy:
Gram ⊝ Cocci
A
- Moraxella catarrhalis
- Neisseria
17
Q
Bacterial Taxonomy:
Gram ⊕ Bacilli
A
- Bacillus
- Clostridium
- Corynebacterium
- Gardnerella (gram variable)
- Lactobacillus
- Listeria
- Mycobacterium (acid fast)
- Cutibacterium (formerly Propionibacterium)
18
Q
Bacterial Taxonomy:
Enteric Gram ⊝ Bacilli
A
- Bacteroides
- Campylobacter
- E. coli
- Enterobacter
- Fusobacterium
- Helicobacter
- Klebsiella
- Proteus
- Pseudomonas
- Salmonella
- Serratia
- Shigella
- Vibrio
- Yersinia
19
Q
Bacterial Taxonomy:
Respiratory Gram ⊝ Bacilli
A
- Acinetobacter baumannii
- Bordetella
- Burkholderia cepacia
- Haemophilus (pleomorphic)
- Legionella (silver stain)
20
Q
Bacterial Taxonomy:
Zoonotic Gram ⊝ Bacilli
A
- Bartonella
- Brucella
- Francisella
- Pasteurella
21
Q
Bacterial Taxonomy:
Branching Filamentous Gram ⊕ Bacteria
A
- Actinomyces
- Nocardia (weakly acid fast)
22
Q
Bacterial Taxonomy:
Pleomorphic Gram ⊝ Bacteria
A
- Anaplasma
- Ehrlichia
- Chlamydiae (Giemsa)
- Rickettsiae (Giemsa)
- Mycoplasma (contains sterols, which do no Gram stain)
- Ureaplasma
23
Q
Bacterial Taxonomy:
Gram ⊝ Spirochetes
A
- Borrelia (Giemsa)
- Leptospira
- Treponema
24
Q
Bacterial Taxonomy:
Staphylococcus
A
Gram ⊕ Cocci in clusters
25
Bacterial Taxonomy:
## Footnote
*Streptococcus*
Gram ⊕ Cocci in chains or pairs
26
Bacterial Taxonomy:
## Footnote
*Enterococcus*
Gram ⊕ Cocci in pairs or short chains
27
Bacterial Taxonomy:
## Footnote
*Moraxella catarrhalis*
Gram ⊝ Cocci
28
Bacterial Taxonomy:
## Footnote
*Neisseria*
Gram ⊝ Cocci
29
Bacterial Taxonomy:
## Footnote
*Bacillus*
Gram ⊕ Bacilli
30
Bacterial Taxonomy:
## Footnote
*Clostridium*
Gram ⊕ Bacilli
31
Bacterial Taxonomy:
## Footnote
*Corynebacterium*
Gram ⊕ Bacilli
32
Bacterial Taxonomy:
## Footnote
*Gardnerella*
Gram ⊕ Bacilli
\*gram variable
33
Bacterial Taxonomy:
## Footnote
*Lactobacillus*
Gram ⊕ Bacilli
34
Bacterial Taxonomy:
## Footnote
*Listeria*
Gram ⊕ Bacilli
35
Bacterial Taxonomy:
## Footnote
*Mycobacterium*
Acid Fast Gram ⊕ Bacilli
36
Bacterial Taxonomy:
*Cutibacterium* (formerly *Propionibacterium*)
Gram ⊕ Bacilli
37
Bacterial Taxonomy:
## Footnote
*Bacteroides*
Enteric Gram ⊝ Bacilli
38
Bacterial Taxonomy:
## Footnote
*Campylobacter*
Enteric Gram ⊝ Bacilli
39
Bacterial Taxonomy:
## Footnote
*E. coli*
Enteric Gram ⊝ Bacilli
40
Bacterial Taxonomy:
## Footnote
*Enterobacter*
Enteric Gram ⊝ Bacilli
41
Bacterial Taxonomy:
## Footnote
*Fusobacterium*
Enteric Gram ⊝ Bacilli
42
Bacterial Taxonomy:
## Footnote
*Helicobacter*
Enteric Gram ⊝ Bacilli
43
Bacterial Taxonomy:
## Footnote
*Klebsiella*
Enteric Gram ⊝ Bacilli
44
Bacterial Taxonomy:
## Footnote
*Proteus*
Enteric Gram ⊝ Bacilli
45
Bacterial Taxonomy:
## Footnote
*Pseudomonas*
Enteric Gram ⊝ Bacilli
46
Bacterial Taxonomy:
## Footnote
*Salmonella*
Enteric Gram ⊝ Bacilli
47
Bacterial Taxonomy:
## Footnote
*Serratia*
Enteric Gram ⊝ Bacilli
48
Bacterial Taxonomy:
## Footnote
*Shigella*
Enteric Gram ⊝ Bacilli
49
Bacterial Taxonomy:
## Footnote
*Vibrio*
Enteric Gram ⊝ Bacilli
50
Bacterial Taxonomy:
## Footnote
*Yersinia*
Enteric Gram ⊝ Bacilli
51
Bacterial Taxonomy:
## Footnote
*Acinetobacter baumannii*
Respiratory Gram ⊝ Bacilli
52
Bacterial Taxonomy:
## Footnote
*Bordetella*
Respiratory Gram ⊝ Bacilli
53
Bacterial Taxonomy:
## Footnote
*Burkholderia cepacia*
Respiratory Gram ⊝ Bacilli
54
Bacterial Taxonomy:
## Footnote
*Haemophilus*
Pleomorphic Respiratory Gram ⊝ Bacilli
55
Bacterial Taxonomy:
## Footnote
*Legionella*
Respiratory Gram ⊝ Bacilli
\*silver stain
56
Bacterial Taxonomy:
## Footnote
*Bartonella*
Zoonotic Gram ⊝ Bacilli
57
Bacterial Taxonomy:
## Footnote
*Brucella*
Zoonotic Gram ⊝ Bacilli
58
Bacterial Taxonomy:
## Footnote
*Francisella*
Zoonotic Gram ⊝ Bacilli
59
Bacterial Taxonomy:
## Footnote
*Pasteurella*
Zoonotic Gram ⊝ Bacilli
60
Bacterial Taxonomy:
## Footnote
*Actinomyces*
Branching Filamentous Gram ⊕ Bacteria
61
Bacterial Taxonomy:
## Footnote
*Nocardia*
Branching Filamentous Gram ⊕ Bacteria
\*weakly acid fast
62
Bacterial Taxonomy:
## Footnote
*Anaplasma*
Pleomorphic Gram ⊝ Bacteria
63
Bacterial Taxonomy:
## Footnote
*Ehrlichia*
Pleomorphic Gram ⊝ Bacteria
64
Bacterial Taxonomy:
## Footnote
*Chlamydiae*
Pleomorphic Gram ⊝ Bacteria
\*Giemsa
65
Bacterial Taxonomy:
## Footnote
*Rickettsiae*
Pleomorphic Gram ⊝ Bacteria
\*Giemsa
66
Bacterial Taxonomy:
## Footnote
*Mycoplasma*
Pleomorphic Gram ⊝ Bacteria
\*contains sterols, which do not Gram stain
67
Bacterial Taxonomy:
## Footnote
*Ureaplasma*
Pleomorphic Gram ⊝ Bacteria
68
Bacterial Taxonomy:
## Footnote
*Borrelia*
Gram ⊝ Spirochetes
\*Giemsa
69
Bacterial Taxonomy:
## Footnote
*Leptospira*
Gram ⊝ Spirochetes
70
Bacterial Taxonomy:
## Footnote
*Treponema*
Gram ⊝ Spirochetes
71
Stains:
first-line lab test in bacterial identification
Gram Stain
* Gram ⊕—thick peptidoglycan layer retains crystal violet dye
* Gram ⊝—thin peptidoglycan layer turns red or pink with counterstain
72
\_\_\_\_\_ do not Gram stain well.
**T**hese **L**ittle **M**icrobes **M**ay **U**nfortunately **L**ack **R**eal **C**olor **B**ut **A**re **E**verywhere
* ***T**reponema*—too thin
* ***L**eptospira*—too thin
* ***M**ycobacteria*—cell wall has high lipid content
* ***M**ycoplasma*—no cell wall
* ***U**reaplasma*—no cell wall
* ***L**egionella*—intracellular
* ***R**ickettsia*—intracellular
* ***C**hlamydia*—intracellular, lacks classic peptidoglycan because of ↓ muramic acid
* ***B**artonella*—intracellular
* ***A**naplasma*—intracellular
* ***E**hrlichia*—intracellular
73
\_\_\_\_\_ are seen through Giemsa stain.
**R**icky got **C**hlamydia as he **T**ried to **P**lease the **B**ored “**Geisha**.”
* ***R**ickettsia*
* ***C**hlamydia*
* ***T**rypanosomes*
* ***P**lasmodium*
* ***B**orrelia*
74
Stains:
* stains glycogen and mucopolysaccharides
* used to diagnose Whipple disease (*Tropheryma whipplei*)
Periodic Acid–Schiff Stain
**PAS**s the **sugar**.
75
Stains:
* acid-fast bacteria (eg. *Mycobacteria*, *Nocardia*; stains mycolic acid in cell wall)
* protozoa (eg. *Cryptosporidium* oocysts)
Ziehl-Neelsen Stain
\*Auramine-Rhodamine Stain is more often used for screening (inexpensive, more sensitive).
| (Carbol Fuchsin)
76
Stains:
* seen through India ink stain
* Mucicarmine can also be used to stain thick polysaccharide capsule red
*Cryptococcus neoformans*
77
Stains:
* fungi (eg. *Coccidioides*, *Pneumocystis jirovecii*)
* *Legionella*
* *Helicobacter pylori*
Silver Stain
78
Stains:
* used to identify many bacteria and viruses
* FTA-ABS for syphilis
Fluorescent Antibody Stain
79
Properties of Growth Media:
* favors the growth of particular organism while preventing growth of other organisms
* eg. Thayer-Martin agar contains antibiotics that allow the selective growth of *Neisseria* by inhibiting the growth of other sensitive organisms
Selective Media
80
Properties of Growth Media:
* yields a color change in response to the metabolism of certain organisms
* contains a pH indicator
* a lactose fermenter like *E. coli* will convert lactose to acidic metabolites → color change
* eg. MacConkey agar
Indicator (Differential) Media
81
Special Culture Requirements:
## Footnote
*H. influenzae*
Chocolate agar
* Factor V (NAD+)
* Factor X (hematin)
82
Special Culture Requirements:
*N. gonorrhoeae*, *N. meningitidis*
Thayer-Martin agar
* selectively favors growth of *Neisseria* by inhibiting growth of gram ⊕ organisms with **V**ancomycin, gram ⊝ organisms except *Neisseria* with **T**rimethoprim and **C**olistin, and fungi with **N**ystatin
**V**ery **T**ypically **C**ultures ***N**eisseria*
83
Special Culture Requirements:
## Footnote
*B. pertussis*
* Bordet-Gengou agar (**Bordet** for ***Bordet**ella)*
* potato extract
* Regan-Lowe medium
* charcoal
* blood
* antibiotic
84
Special Culture Requirements:
## Footnote
*C. diphtheriae*
* Tellurite agar
* Löffler medium
85
Special Culture Requirements:
## Footnote
*M. tuberculosis*
Löwenstein-Jensen agar
86
Special Culture Requirements:
## Footnote
*M. pneumoniae*
Eaton agar
* requires cholesterol
87
Special Culture Requirements:
Lactose-Fermenting Enterics
MacConkey agar
* fermentation produces acid causing colonies to turn pink
88
Special Culture Requirements:
## Footnote
*E. coli*
Eosin–Methylene Blue (EMB) agar
* colonies with green metallic sheen
89
Special Culture Requirements:
## Footnote
*Legionella*
Charcoal Yeast Extract agar
* buffered with cysteine and iron
90
\_\_\_\_\_ use an O2-dependent system to generate ATP.
Aerobes
91
Aerobes
**N**agging **P**ests **M**ust **B**reathe.
* ***N**ocardia*
* ***P**seudomonas aeruginosa*
* ***M**yco**B**acterium tuberculosis*
92
Reactivation of *M .tuberculosis* (eg. after immunocompromise or TNF-α inhibitor use) has a predilection for the \_\_\_\_\_.
apices of the lung
93
\_\_\_\_ lack catalase and/or superoxide dismutase and are thus susceptible to oxidative damage. Generally foul smelling (short-chain fatty acids), are difficult to culture, and produce gas in tissue (CO2 and H2).
Anaerobes
94
Anaerobes
Anaerobes **C**an’t **B**reathe **F**resh **A**ir.
* ***C**lostridium*
* ***B**acteroides*
* ***F**usobacterium*
* ***A**ctinomyces israelii*
95
Anaerobes are normal flora in the \_\_\_\_\_, typically pathogenic elsewhere.
GI tract
96
\_\_\_\_\_ are ineffective against anaerobes becaus these antibiotics require O2 to enter into bacterial cell.
Aminoglycosides
Amin**O2**glycosides
97
\_\_\_\_\_ may use O2 as a terminal electron acceptor to generate ATP, but can also use fermentation and other O2-independent pathways.
Facultative Anaerobes
98
Facultative Anaerobes
* *Streptococci*
* *Staphylococci*
* Enteric Gram ⊝ Bacteria
99
Obligate Intracellular Bacteria
Stay inside (cells) when it is **R**eally **CH**illy and **CO**ld.
* ***R**ickettsia*
* ***CH**lamydia*
* ***CO**xiella*
\*rely on host ATP
100
Facultative Intracellular Bacteria
**S**ome **N**asty **B**ugs **M**ay **L**ive **F**acultative**LY**.
* ***S**almonella*
* ***N**eisseria*
* ***B**rucella*
* ***M**ycobacterium*
* ***L**isteria*
* ***F**rancisella*
* ***L**egionella*
* ***Y**ersinia pestis*
101
The capsules of _____ serve as an antiphagocytic virulence factor. They are opsonized, and then cleared by spleen. Capsular polysaccharide + protein conjugate serves as an antigen in vaccines.
Encapsulated Bacteria
102
Encapsulated Bacteria
**P**lease **SHiNE** my **SK**i**S**.
* ***P**seudomonas aeruginosa*
* ***S**treptococcus pneumoniae*
* ***H**aemophilus* ***i**nfluenzae* type b
* ***N**eisseria meningitidis*
* ***E**scherichia coli*
* ***S**almonella*
* ***K**lebsiella* *pneumoniae*
* Group B ***S**trep.*
103
Asplenics have ↓ opsonizing ability and thus ↓ risk for severe infections; need vaccines to protect against \_\_\_\_\_.
**N**o **S**pleen **H**ere
* ***N**. meningitidis*
* ***S**. pneumoniae*
* ***H**. influenzae*
104
\_\_\_\_\_ containing polysaccharide capsule antigens are conjugated to a carrier protein, enhancing immunogenicity by promoting T-cell activation and subsequent class switching. A polysaccharide antigen alone cannot be presented to T cells.
Encapsulated Bacteria Vaccines
105
Encapsulated Bacteria Vaccines
* Pneumococcal vaccines:
* PCV13 (pneumococcal conjugate vaccine)
* PPSV23 (pneumococcal polysaccharide vaccine with no conjugated protein)
* *H. influenzae* type b (conjugate vaccine)
* Meningococcal vaccine (conjugate vaccine)
106
Urease-Positive Organisms
**P**ee **CHUNKSS**
* ***P**roteus*
* ***C**ryptococcus*
* ***H**. pylori*
* ***U**reaplasma*
* ***N**ocardia*
* ***K**lebsiella*
* ***S**. epidermidis*
* ***S**. saprophyticus*
\*predisposes to struvite (ammonium magnesium phosphate) stones, particularly Proteus
107
\_\_\_\_\_ hydrolyzes urea to release ammonia and CO2 → ↑ pH.
Urease
108
\_\_\_\_\_ degrades H2O2 into H2O and bubbles of O2 before it can be converted to microbicidal products by the enzyme myeloperoxidase.
Catalase
109
People with _____ (NADPH oxidase deficiency) have recurrent infections with certain catalase ⊕ organisms.
Chronic Granulomatous Disease
110
Catalase-Positive Organisms
**Cat**s **N**eed **PLACESS** to **B**elch their **H**airballs.
* ***N**ocardia*
* ***P**seudomonas*
* ***L**isteria*
* ***A**spergillus*
* ***C**andida*
* ***E**. coli*
* ***S**taphylococci*
* ***S**erratia*
* ***B**. cepacia*
* ***H**. pylori*
111
Pigment-Producing Bacteria:
yellow “sulfur” granules—composed of filaments of bacteria
*Actinomyces israelii*
**Israel** has **yellow** sand.
112
Pigment-Producing Bacteria:
yellow pigment
*S. aureus*
**Au**reus (Latin) = **gold**
113
Pigment-Producing Bacteria:
blue-green pigment (pyocyanin and pyoverdin)
*P. aeruginosa*
**Aerug**ula is **green**.
114
Pigment-Producing Bacteria:
red pigment
*Serratia marcescens*
**red Sriracha** hot sauce
115
In Vivo Biofilm Producing Bacteria:
catheter and prosthetic device infections
*S. epidermidis*
116
In Vivo Biofilm Producing Bacteria:
* dental plaques
* infective endocarditis
Viridans streptococci
* *S. mutans*
* *S. sanguinis*
117
In Vivo Biofilm Producing Bacteria:
* respiratory tree colonization in patients with cystic fibrosis
* ventilator-associated pneumonia
* contact lens–associated keratitis
*P. aeruginosa*
118
In Vivo Biofilm Producing Bacteria:
otitis media
Nontypeable (Unencapsulated) *H. influenzae*
119
\_\_\_\_\_ promote evasion of host immune response.
Bacterial Virulence Factors
120
Bacterial Virulence Factors:
* binds Fc region of IgG
* prevents opsonization and phagocytosis
* expressed by *S. aureus*
Protein A
121
Bacterial Virulence Factors:
* enzyme that cleaves IgA, allowing bacteria to adhere to and colonize mucous membranes
* secreted by *S. pneumoniae*, *H. influenzae* type b, and *Neisseria*
IgA protease
**SHiN**
* ***S**. pneumoniae*
* ***H**. **i**nfluenzae* type b
* ***N**eisseria*
122
Bacterial Virulence Factors:
* helps prevent phagocytosis
* expressed by group A streptococci
* shares similar epitopes to human cellular proteins (molecular mimicry)
* possibly underlies the autoimmune response seen in acute rheumatic fever
M protein
123
\_\_\_\_\_ is also known as “injectisome.” It's a needle-like protein appendage facilitating direct delivery of toxins from certain gram ⊝ bacteria (eg. *Pseudomonas*, *Salmonella*, *Shigella*, *E. coli*) to eukaryotic host cell.
Type III Secretion System
124
Bacterial Genetics:
* competent bacteria can bind and import short pieces of environmental naked bacterial chromosomal DNA (from bacterial cell lysis)
* transfer and expression of newly transferred genes
* a feature of many bacteria, especially *S. pneumoniae*, *H. influenzae* type b, and *Neisseria*
* adding deoxyribonuclease degrades naked DNA, preventing \_\_\_\_\_
Transformation
125
Bacterial Genetics:
Conjugation (F+ × F–)
* F+ plasmid contains genes required for sex pilus and conjugation
* bacteria without this plasmid are termed F–
* sex pilus on F+ bacterium contacts F− bacterium
* a single strand of plasmid DNA is transferred across the conjugal bridge (“mating bridge”)
* no transfer of chromosomal DNA
126
Bacterial Genetics:
Conjugation (Hfr × F–)
* F+ plasmid can become incorporated into bacterial chromosomal DNA, termed High-frequency recombination (Hfr) cell
* transfer of leading part of plasmid and a few flanking chromosomal genes
* High-frequency recombination may integrate some of those bacterial genes
* recipient cell remains F– but now may have new bacterial genes
127
Bacterial Genetics:
* a packaging “error”
* lytic phage infects bacterium, leading to cleavage of bacterial DNA
* parts of bacterial chromosomal DNA may become packaged in phage capsid
* phage infects another bacterium, transferring these genes
Generalized Transduction
128
Bacterial Genetics:
* an “excision” event
* lysogenic phage infects bacterium
* viral DNA incorporates into bacterial chromosome
* when phage DNA is excised, flanking bacterial genes may be excised with it
* DNA is packaged into phage capsid and can infect another bacterium
Specialized Transduction
\*Genes for the following 5 bacterial toxins are encoded in a lysogenic phage (**ABCD**’**S**):
* Group **A** strep erythrogenic toxin
* **B**otulinum toxin
* **C**holera toxin
* **D**iphtheria toxin
* **S**higa toxin
129
Bacterial Genetics:
* segment of DNA (eg. transposon) that can “jump” (copy/excise and reinsert) from one location to another, can transfer genes from plasmid to chromosome and vice versa
* this is a critical process in creating plasmids with multiple antibiotic resistance which can be transferred across species lines (eg. Tn1546 carrying vanA gene from vancomycin-resistant *Enterococcus* to *S. aureus*)
Transposition
130
Bacterial Genetics:
* formed by some bacteria when nutrients are limited
* lack metabolic activity
* highly resistant to heat and chemicals
* core contains dipicolinic acid
* must autoclave to kill by steaming at 121°C for 15 minutes
Spores
131
Spore-Forming Bacteria
* *Bacillus anthracis*—anthrax
* *Bacillus cereus*—food poisoning
* *Clostridium botulinum*—botulism
* *Clostridium difficile*—pseudomembranous colitis
* *Clostridium perfringens*—gas gangrene
* *Clostridium tetani*—tetanus
132
Exotoxins:
Source
certain species of gram ⊕ and gram ⊝ bacteria
133
Exotoxins:
Cell Secretion
yes
134
Exotoxins:
Chemical Composition
Polypeptide
135
Exotoxins:
Location of Genes
* Plasmid
* Bacteriophage
136
Exotoxins:
Adverse Effects
High
\*fatal dose on the order of 1 μg
137
Exotoxins:
Clinical Effects
Varied
138
Exotoxins:
Mode of Action
Varied
139
Exotoxins:
Antigenicity
induces high-titer antibodies called antitoxins
140
Exotoxins:
Vaccines
Toxoids
141
Exotoxins:
Heat Stability
destroyed rapidly at 60°C (except staphylococcal enterotoxin and *E. coli* heatstable toxin)
142
Exotoxins:
Typical Diseases
* Tetanus
* Botulism
* Diphtheria
143
Endotoxins:
Source
outer cell membrane of most gram ⊝ bacteria
144
Endotoxins:
Cell Secretion
No
145
Endotoxins:
Chemical Composition
Lipid A component of LPS (structural part of bacteria; released when lysed)
146
Endotoxins:
Location of Genes
Bacterial Chromosome
147
Endotoxins:
Adverse Effects
Low
\*fatal dose on the order of hundreds of micrograms
148
Endotoxins:
Clinical Effects
* fever
* shock (hypotension)
* DIC
149
Endotoxins:
Mode of Action
induces TNF, IL-1, and IL-6
150
Endotoxins:
Antigenicity
poorly antigenic
151
Endotoxins:
Vaccines
* no toxoids formed
* no vaccine available
152
Endotoxins:
Heat Stability
stable at 100°C for 1 hr
153
Endotoxins:
Typical Diseases
* Meningococcemia
* Sepsis by gram ⊝ rods
154
Exotoxins:
* two-component toxin (or three for anthrax) with B enabling binding and triggering uptake (endocytosis) of the active A component
* the A components are usually ADP ribosyltransferases; others have enzymatic activities
AB toxin
155
Exotoxins:
inhibit protein synthesis
* *Corynebacterium* *diphtheriae—*Diphtheria toxin
* *Pseudomonas* *aeruginosa—*Exotoxin A
* *Shigella spp.—*Shiga toxin (ST)
* *Enterohemorrhagic* *E. coli—*Shiga-like toxin (SLT)
156
Exotoxins:
* AB toxin
* inactivate elongation factor (EF-2)
* pharyngitis with pseudomembranes in throat and severe lymphadenopathy (bull neck)
*Corynebacterium diphtheriae*—Diphtheria toxin
157
Exotoxins:
* AB toxin
* inactivate elongation factor (EF-2)
* host cell death
*Pseudomonas aeruginosa*—Exotoxin A
158
Exotoxins:
* AB toxin
* inactivate 60S ribosome by removing adenine from rRNA
* GI mucosal damage → dysentery
* enhances cytokine release, causing hemolyticuremic syndrome (HUS)
*Shigella* spp.—Shiga toxin (ST)
159
Exotoxins:
* AB toxin
* inactivate 60S ribosome by removing adenine from rRNA
* enhances cytokine release, causing HUS (prototypically in EHEC serotype O157:H7).
* unlike *Shigella*, EHEC does not invade host cells
Enterohemorrhagic *E. coli*—Shiga-like toxin (SLT)
160
Exotoxins:
increase fluid secretion
* Enterotoxigenic *E. coli*
* Heat-labile toxin (LT)
* Heat-stable toxin (ST)
* *Bacillus anthracis*—Edema toxin
* *Vibrio cholerae*—Cholera toxin
161
Exotoxins:
* AB toxin
* overactivates adenylate cyclase (↑ cAMP) → ↑ Cl− secretion in gut and H2O efflux
* watery diarrhea
Enterotoxigenic *E. coli*—Heat-labile toxin (LT)
**Labile** in the **A**ir (**A**denylate cyclase)
162
Exotoxins:
* overactivates guanylate cyclase (↑ cGMP) → ↓ resorption of NaCl and H2O in gut
* watery diarrhea
Enterotoxigenic *E. coli*—Heat-stable toxin (ST)
**Stable** on the **G**round (**G**uanylate cyclase)
163
Exotoxins:
* AB toxin
* mimics adenylate cyclase (↑ cAMP)
* likely responsible for characteristic edematous borders of black eschar in cutaneous anthrax
*Bacillus anthracis*—Edema toxin
164
Exotoxins:
* AB toxin
* overactivates adenylate cyclase (↑ cAMP) by permanently activating Gs → ↑ Cl− secretion in gut and H2O efflux
* voluminous “rice-water” diarrhea
*Vibrio cholerae*—Cholera toxin
165
Exotoxins:
inhibit phagocytic ability
*Bordetella pertussis*—Pertussis toxin
166
Exotoxins:
* overactivates adenylate cyclase (↑ cAMP) by disabling Gi, impairing phagocytosis to permit survival of microbe
* Whooping Cough—child coughs on expiration and “whoops” on inspiration (toxin may not actually be a cause of cough; can cause “100-day cough” in adults)
*Bordetella pertussis*—Pertussis toxin
167
Exotoxins:
inhibit release of neurotransmitter
* *Clostridium tetani*—Tetanospasmin
* *Clostridium botulinum*—Botulinum toxin
168
Exotoxins:
* AB toxin
* protease that cleaves SNARE (soluble NSF attachment protein receptor), a set of proteins required for neurotransmitter release via vesicular fusion
* prevents release of inhibitory (GABA and glycine) neurotransmitters from Renshaw cells in spinal cord → spastic paralysis, risus sardonicus, trismus (lockjaw)
*Clostridium tetani*—Tetanospasmin
169
Exotoxins:
* AB toxin
* protease that cleaves SNARE (soluble NSF attachment protein receptor), a set of proteins required for neurotransmitter release via vesicular fusion
* prevents release of stimulatory (ACh) signals at neuromuscular junction → flaccid paralysis (floppy baby)
*Clostridium botulinum*—Botulinum toxin
170
Exotoxins:
lyse cell membranes
* *Clostridium perfringens*—Alpha toxin
* *Streptococcus pyogenes*—Streptolysin O
171
Exotoxins:
* phospholipase (lecithinase) that degrades tissue and cell membranes
* degradation of phospholipids → myonecrosis (“gas gangrene”) and hemolysis (“double zone” of hemolysis on blood agar)
*Clostridium perfringens*—Alpha toxin
172
Exotoxins:
* protein that degrades cell membrane
* lyses RBCs
* contributes to β-hemolysis
* host antibodies against toxin (ASO) used to diagnose rheumatic fever
*Streptococcus pyogenes*—Streptolysin O
173
Exotoxins:
superantigens causing shock
* *Staphylococcus aureus*—Toxic Shock Syndrome toxin (TSST-1)
* *Streptococcus pyogenes*—Erythrogenic exotoxin A
174
Exotoxins:
* cross-links β region of TCR to MHC class II on APCs outside of the antigen binding site → overwhelming release of IL-1, IL-2, IFN-γ, and TNF-α → shock
* Toxic Shock Syndrome: fever, rash, shock
*Staphylococcus aureus*—Toxic Shock Syndrome toxin (TSST-1)
175
Exotoxins:
* cross-links β region of TCR to MHC class II on APCs outside of the antigen binding site → overwhelming release of IL-1, IL-2, IFN-γ, and TNF-α → shock
* Toxic Shock–like Syndrome: fever, rash, shock;
scarlet fever
*Streptococcus pyogenes*—Erythrogenic exotoxin A
176
Endotoxin
**ENDOTOXINS**:
* **E**dema
* **N**itric oxide
* **D**IC/**D**eath
* **O**uter membrane
* **T**NF-α
* **O**-antigen + core polysaccharide + lipid A
* e**X**tremely heat stable
* **I**L-1 and **I**L-6
* **N**eutrophil chemotaxis
* **S**hock
177
\_\_\_\_\_ are the glycolipid LPS molecules found in the outer membrane of gram ⊝ bacteria (both cocci and rods).
Endotoxins
178
Endotoxins are composed of \_\_\_\_\_.
* O antigen
* core polysaccharide
* lipid A—toxic component
179
Endotoxins are released upon _____ or by living cells by _____ (vs. exotoxin, which is actively secreted).
* cell lysis
* blebs detaching from outer surface membrane
180
The three main effects of endotoxins are \_\_\_\_\_.
* macrophage activation (TLR4/CD14)
* complement activation
* tissue factor activation
181
Gram-Positive Lab Algorithm
182
Gram-Positive Cocci Antibiotic Test:
Staphylococci
**No**vobiocin
* ***S**aprophyticus* is **R**esistant
* ***E**pidermidis* is **S**ensitive
On the office’s “**staph**” retreat, there was **No** **S**t**RES**s.
183
Gram-Positive Cocci Antibiotic Test:
Streptococci
**O**ptochin
* **V**iridans is **R**esistant
* **P**neumoniae is **S**ensitive
**OVRPS** (overpass)
**B**acitracin
* group **B** strep are **R**esistant
* group **A** strep are **S**ensitive
B-BRAS.
184
\_\_\_\_\_ are gram ⊕ cocci which partially reduce hemoglobin causing greenish or brownish color without clearing around growth on blood agar.
α-Hemolytic Bacteria
185
α-Hemolytic Bacteria
* *Streptococcus pneumoniae*
* **catalase ⊝
* optochin sensitive
* Viridans streptococci
* catalase ⊝
* optochin resistant
186
\_\_\_\_\_ are gram ⊕ cocci which cause complete lysis of RBCs → clear area surrounding colony on blood agar.
β-Hemolytic Bacteria
187
β-Hemolytic Bacteria
* *Staphylococcus aureus*
* **catalase and coagulase ⊕
* *Streptococcus pyogenes*
* group A strep
* catalase ⊝ and bacitracin sensitive
* *Streptococcus agalactiae*
* **group B strep
* catalase ⊝ and bacitracin resistant
188
Bacteria:
* Gram ⊕
* β-hemolytic
* Catalase ⊕
* Coagulase ⊕
* cocci in clusters
* Protein A (virulence factor) binds Fc-IgG, inhibiting complement activation and phagocytosis
* commonly colonizes the nares, ears, axilla, and groin
*Staphylococcus aureus*
189
Bacteria:
* _Inflammatory Disease_—skin infections, organ abscesses, pneumonia (often after influenza virus infection), endocarditis, septic arthritis, and osteomyelitis
* _Toxin-Mediated Disease_—toxic shock syndrome (TSST-1), scalded skin syndrome (exfoliative toxin), rapid-onset food poisoning (enterotoxins)
*Staphylococcus aureus*
190
Bacteria:
* important cause of serious nosocomial and community-acquired infections
* resistant to methicillin and nafcillin because of altered penicillin-binding protein
MRSA (Methicillin-Resistant *S. aureus*)
191
\_\_\_\_\_ is a superantigen that binds to MHC II and T-cell receptor, resulting in polyclonal T-cell activation.
TSST-1
192
\_\_\_\_\_ causes fever, vomiting, rash, desquamation, shock, and end-organ failure. It results in ↑ AST, ↑ ALT, ↑ bilirubin. Associated with prolonged use of vaginal tampons or nasal packing.
Staphylococcal Toxic Shock Syndrome (TSS)
193
\_\_\_\_\_ causes a toxic shock–like syndrome associated with painful skin infection.
*Streptococcus pyogenes*
194
\_\_\_\_\_ food poisoning due to ingestion of preformed toxin → short incubation period (2–6 hr) followed by nonbloody diarrhea and emesis. Enterotoxin is heat stable → not destroyed by cooking.
*S. aureus*
195
Bad _____ make coagulase and toxins. Forms fibrin clot around self abscess.
*S. aureus*
196
Bacteria:
* Gram ⊕
* Catalase ⊕
* Coagulase ⊝
* Urease ⊕
* cocci in clusters
* Novobiocin sensitive
* does not ferment mannitol
* normal flora of skin
* contaminates blood cultures
* infects prosthetic devices (eg. hip implant, heart valve) and IV catheters by producing adherent biofilms
*Staphylococcus epidermidis*
197
Bacteria:
* Gram ⊕
* Catalase ⊕
* Coagulase ⊝
* Urease ⊕
* cocci in clusters
* Novobiocin resistant
* normal flora of female genital tract and perineum
* second most common cause of uncomplicated UTI in young women (most common is *E. coli*)
*Staphylococcus saprophyticus*
198
Bacteria:
* Gram ⊕
* lancet-shaped diplococci
* encapsulated
* IgA protease
* Optochin sensitive
* associated with “rusty” sputum, sepsis in patients with sickle cell disease, and asplenic patients
* no virulence without capsule
*Streptococcus pneumoniae*
199
Bacteria:
most common cause of meningitis, otitis media (in children), pneumonia, and sinusitis
*Streptococcus pneumoniae*
**MOPS** spread **pneumonia**.
* **M**eningitis
* **O**titis media (in children)
* **P**neumonia
* **S**inusitis
200
Bacteria:
* Gram ⊕
* α-hemolytic cocci
* resistant to optochin
* normal flora of the oropharynx
Viridans Group Streptococci
Viridans group strep live in the mouth, because they are not afraid **of-the-chin** (**op-to-chin** resistant).
201
Viridans Group Streptococci:
cause dental caries
* *Streptococcus mutans*
* *SStreptococcus mitis*
202
Viridans Group Streptococci:
makes dextrans that bind to fibrin-platelet aggregates on damaged heart valves, causing subacute bacterial endocarditis
*Streptococcus sanguinis*
Sanguinis = **blood**.
Think, “there is lots of **blood** in the **heart**” (endocarditis).
203
Bacteria:
* Gram ⊕ cocci in chains
* Bacitracin sensitive
* β-hemolytic
* Pyrrolidonyl Arylamidase (PYR) ⊕
* Hyaluronic acid capsule and M protein inhibit phagocytosis
* antibodies to M protein enhance host defense but can give rise to rheumatic fever
*Streptococcus pyogenes* (Group A Streptococci)
204
Bacteria:
* _Pyogenic_—pharyngitis, cellulitis, impetigo (“honey-crusted” lesions), erysipelas
* _Toxigenic_—scarlet fever, toxic shock–like syndrome, necrotizing fasciitis
* _Immunologic_—rheumatic fever, glomerulonephritis
*Streptococcus pyogenes* (Group A Streptococci)
205
ASO titer or anti-DNase B antibodies indicate recent _____ infection.
*Streptococcus pyogenes* (Group A Streptococci)
206
\_\_\_\_\_ pharyngitis can result in rheumatic fever and glomerulonephritis.
*Streptococcus pyogenes* (Group A Streptococci)
**Ph**aryngitis can result in rheumatic “**ph**ever” and glomerulone**ph**ritis.
207
\_\_\_\_\_ strains causing impetigo can induce glomerulonephritis.
*Streptococcus pyogenes* (Group A Streptococci)
208
\_\_\_\_\_ causes blanching, sandpaper-like body rash, strawberry tongue, and circumoral pallor in the setting of group A streptococcal pharyngitis (erythrogenic toxin ⊕).
Scarlet Fever
209
Bacteria:
* Gram ⊕ cocci
* Bacitracin resistant
* β-hemolytic
* colonizes vagina
* causes pneumonia, meningitis, and sepsis, mainly in babies.
* produces CAMP factor, which enlarges the area of hemolysis formed by *S. aureus*. (Note: CAMP stands for the authors of the test, not cyclic AMP.)
* Hippurate test ⊕
* PYR ⊝
*Streptococcus agalactiae* (Group B Streptococci)
Group **B** is **β**-hemolytic for **B**abies.
210
Pregnant women should be screened for _____ at 35–37 weeks of gestation with rectal and vaginal swabs.
*Streptococcus agalactiae* (Group B Streptococci)
211
Patients with ⊕ _____ culture should receive intrapartum penicillin prophylaxis.
*Streptococcus agalactiae* (Group B Streptococci)
212
Bacteria:
* Gram ⊕ cocci
* colonizes the gut
* *S. gallolyticus* (\_\_\_\_\_ biotype 1) can cause bacteremia and subacute endocarditis and is associated with colon cancer
*Streptococcus bovis*
**B**ovis in the **B**lood = **C**ancer in the **C**olon
213
Bacteria:
* Gram ⊕ cocci
* Penicillin G resistant
* Catalase ⊝
* PYR ⊕
* normal colonic flora that cause UTI, biliary tract infections, and subacute endocarditis (following GI/GU procedures)
* VRE (vancomycin-resistant \_\_\_\_\_) are an important cause of nosocomial infection
* more resilient than streptococci, can grow in 6.5% NaCl and bile (lab test)
Enterococci
* *E. faecalis*
* *E. faecium*
214
Bacteria:
* Gram ⊕
* spore-forming rod
* produces anthrax toxin
* the only bacterium with a polypeptide capsule (contains d-glutamate)
* colonies show a halo of projections, sometimes referred to as “medusa head” appearance
*Bacillus anthracis*
215
\_\_\_\_\_ causes painless papule surrounded by vesicles → ulcer with black eschar ( A ) (painless, necrotic) → uncommonly progresses to bacteremia and death.
Cutaneous Anthrax
(*Bacillus anthracis*)
216
\_\_\_\_\_ is caused by inhalation of _____ spores → flu-like symptoms that rapidly progress to fever, pulmonary hemorrhage, mediastinitis, and shock. Also known as woolsorter’s disease. CXR may show widened mediastinum.
Pulmonary anthrax
(*Bacillus anthracis*)
217
Bacteria:
* Gram ⊕ rod.
* causes food poisoning
* spores survive cooking rice (also known as reheated rice syndrome)
* keeping rice warm results in germination of spores and enterotoxin formation
* _Emetic Type_
* usually seen with rice and pasta
* nausea and vomiting
* onset within 1–5 hr
* caused by cereulide, a preformed toxin
* _Diarrheal Type_
* watery, nonbloody diarrhea and GI pain
* onset within 8–18 hr
*Bacillus cereus*
218
Bacteria:
* Gram ⊕
* spore-forming
* obligate anaerobic rods
Clostridia (with exotoxins)
219
Bacteria:
* produces tetanospasmin, an exotoxin causing tetanus
* causes spastic paralysis, trismus (lockjaw), risus sardonicus (raised eyebrows and open grin), and opisthotonos (spasms of spinal extensors)
*Clostridium tetani*
220
\_\_\_\_\_ are proteases that cleave SNARE proteins for
neurotransmitters. They blocks release of inhibitory neurotransmitters, GABA and glycine, from Renshaw cells in spinal cord.
* Tetanus toxin
* Botulinum toxin
221
Tetanus is treated with \_\_\_\_\_.
* Antitoxin +/− Vaccine Booster
* Antibiotics
* Diazepam (for muscle spasms)
* Wound Debridement
222
Bacteria:
* produces a heat-labile toxin that inhibits ACh release at the neuromuscular junction, causing botulism
* in adults, disease is caused by ingestion of preformed toxin
* in babies, ingestion of spores (eg. in honey) leads to disease (floppy baby syndrome)
* local botox injections used to treat focal dystonia, achalasia, and muscle spasms
* used for cosmetic reduction of facial wrinkles
*Clostridium botulinum*
**Bot**ulinum is from bad **bot**tles of food, juice, and honey (causes a descending flaccid paralysis).
223
The symptoms of botulism are \_\_\_\_\_.
**4 D**’s:
* **D**iplopia
* **D**ysarthria
* **D**ysphagia
* **D**yspnea
224
Botulism is treated with \_\_\_\_\_.
Human Botulinum Immunoglobulin
225
Bacteria:
* produces α toxin (lecithinase, a phospholipase) that can cause myonecrosis (gas gangrene; presents as soft tissue crepitus) and hemolysis
* spores can survive in undercooked food
* when ingested, bacteria release heat-labile enterotoxin → food poisoning.
*Clostridium perfringens*
**Perf**ringens **perf**orates a gangrenous leg.
226
Bacteria:
* produces 2 toxins
* _Toxin A_
* enterotoxin,
* binds to brush border of gut and alters fluid secretion
* _Toxin B_
* cytotoxin
* disrupts cytoskeleton via actin depolymerization
* both toxins lead to diarrhea → pseudomembranous colitis
* often 2° to antibiotic use, especially Clindamycin or Ampicillin
* associated with PPIs
*Clostridium difficile*
**Di**fficile causes **di**arrhea.
227
*Clostridium difficile* is diagnosed by \_\_\_\_\_.
* PCR
* antigen detection of one or both toxins in stool
228
*Clostridium difficile* is treated with \_\_\_\_\_.
* Metronidazole
* Oral Vancomycin
229
Recurrent *Clostridium difficile* is treated with \_\_\_\_\_.
* consider repeating prior regimen
* Fidaxomicin
* Fecal Microbiota Transplant
230
Bacteria:
* Gram ⊕ rod
* black colonies on cystine-tellurite agar
* transmitted via respiratory droplets
* causes diphtheria via exotoxin encoded by β-prophage
* potent exotoxin inhibits protein synthesis via ADP-ribosylation of EF-2
* symptoms include pseudomembranous pharyngitis (grayish-white membrane) with lymphadenopathy, myocarditis, and arrhythmias
* lab diagnosis based on gram ⊕ rods with metachromatic (blue and red) granules and ⊕ Elek test for toxin
* toxoid vaccine prevents diphtheria
*Corynebacterium diphtheriae*
Coryne = club shaped
**ABCDEFG**:
* **A**DP-ribosylation
* **β**-prophage
* ***C**orynebacterium*
* ***D**iphtheriae*
* **E**longation **F**actor 2
* **G**ranules
231
Bacteria:
* Gram ⊕
* facultative intracellular rod
* acquired by ingestion of unpasteurized dairy products and cold deli meats, via transplacental transmission, or by vaginal transmission during birth
* grows well at refrigeration temperatures (4°–10°C; “cold enrichment”)
*Listeria monocytogenes*
232
Bacteria:
* forms “rocket tails” via actin polymerization that allow intracellular movement and cell-to-cell spread across cell membranes, thereby avoiding antibody
* characteristic tumbling motility in broth
*Listeria monocytogenes*
233
Bacteria:
* amnionitis, septicemia, and spontaneous abortion in pregnant women
* granulomatosis infantiseptica
* neonatal meningitis
* meningitis in immunocompromised patients
* mild, selflimited gastroenteritis in healthy individuals
*Listeria monocytogenes*
234
*Listeria monocytogenes* is treated with \_\_\_\_\_.
Ampicillin
235
Bacteria:
* gram ⊕
* form long, branching filaments resembling fungi
* *Nocardia*
* *Actinomyces*
236
Bacteria:
* aerobe
* acid fast (weak)
* found in soil
* causes pulmonary infections in immunocompromised (can mimic TB but with ⊝ PPD)
* cutaneous infections after trauma in immunocompetent
* can spread to CNS
* treated with sulfonamides (TMP-SMX)
*Nocardia*
237
Bacteria:
* anaerobe
* not acid fast
* normal oral, reproductive, and GI flora
* causes oral/facial abscesses that drain through sinus tracts
* often associated with dental caries/extraction and other maxillofacial trauma
* forms yellow “sulfur granules”
* can cause PID with IUDs
* treated with Penicillin
*Actinomyces*
238
*Nocardia* is treated with _____ while *Actinomyces* is treated with \_\_\_\_\_.
**SNAP**:
* **S**ulfonamides—***N**ocardia*
* ***A**ctinomyces*—**P**enicillin
239
Mycobacteria:
* causes TB
* often resistant to multiple drugs
*Mycobacterium tuberculosis*
240
Mycobacteria:
* causes disseminated, non-TB disease in AIDS
* often resistant to multiple drugs
* prophylaxis with azithromycin when CD4+ count \< 50 cells/mm3
*Mycobacterium avium–intracellulare*
241
Mycobacteria:
cervical lymphadenitis in children
*Mycobacterium scrofulaceum*
242
Mycobacteria:
hand infection in aquarium handlers
*Mycobacterium marinum*
243
All mycobacteria are _____ organisms (pink rods).
acid-fast
244
TB symptoms include \_\_\_\_\_.
* fever
* night sweats
* weight loss
* cough (nonproductive or productive)
* hemoptysis
245
\_\_\_\_\_ creates a “serpentine cord” appearance in virulent *M. tuberculosis* strains; activates macrophages (promoting granuloma formation) and induces release of TNF-α.
Cord Factor
246
\_\_\_\_\_ (surface glycolipids) inhibit phagolysosomal fusion.
Sulfatides
247
Tuberculosis
248
Tuberculosis:
PPD __ if current infection or past exposure.
PPD ⊕
249
Tuberculosis:
PPD __ if no infection and in sarcoidosis or HIV infection (especially with low CD4+ cell count).
PPD ⊝
250
Tuberculosis:
has fewer false positives from BCG vaccination
Interferon-γ Release Assay (IGRA)
251
Characteristics of 2° Tuberculosis include \_\_\_\_\_.
* Caseating Granulomas with central necrosis
* Langhans Giant Cells
252
Mycobacteria:
* caused by *Mycobacterium leprae*, an acid-fast bacillus that likes cool temperatures (infects skin and superficial nerves—“glove and stocking” loss of sensation) and cannot be grown in vitro
* diagnosed via skin biopsy or tissue PCR
* reservoir in US: armadillos
Leprosy (Hansen disease)
253
Leprosy:
* presents diffusely over the skin, with leonine (lion-like) facies
* communicable (high bacterial load)
* characterized by low cell-mediated immunity with a humoral Th2 response
* can be lethal
Lepromatous
**L**epromatous form can be **L**ethal.
254
Leprosy:
* limited to a few hypoesthetic, hairless skin plaques
* characterized by high cell-mediated immunity with a largely Th1-type immune response and low bacterial load
Tuberculoid
255
Leprosy (Hansen disease) is treated with \_\_\_\_\_.
* Tuberculoid
* Dapsone
* Rifampin
* Lepromatous
* Lofazimine
* Dapsone
* Rifampin
256
Gram-Negative Lab Algorithm
257
Bacteria:
* Gram ⊝ diplococci
* metabolizes glucose
* produces IgA proteases
* contains lipooligosaccharides (LOS) with strong endotoxin activity
*Neisseria*
258
Bacteria:
* no polysaccharide capsule
* often intracellular (within neutrophils)
* Maltose not fermented
* no vaccine due to antigenic variation of pilus proteins
* sexually or perinatally transmitted
* causes gonorrhea, septic arthritis, neonatal conjunctivitis (2–5 days after birth), pelvic inflammatory disease (PID), and Fitz-Hugh-Curtis syndrome
* condoms ↓ sexual transmission
*Neisseria gonorrhoeae*
**G**onococci ferment **G**lucose.
259
\_\_\_\_\_ eye ointment prevents neonatal blindness from *Neisseria gonorrhoeae.*
Erythromycin
260
*Neisseria gonorrhoeae* is treated with \_\_\_\_\_.
Ceftriaxone (+ Azithromycin or Doxycycline, for possible chlamydial coinfection)
261
Bacteria:
* polysaccharide capsule
* Maltose fermentation
* vaccine (type B vaccine not widely available)
* transmitted via respiratory and oral secretions
* causes meningococcemia with petechial hemorrhages and gangrene of toes, meningitis, Waterhouse-Friderichsen syndrome (adrenal insufficiency, fever, DIC, shock)
*Neisseria meningitidis*
**M**enin**G**ococci ferment **M**altose and **G**lucose.
262
\_\_\_\_\_ are given to close contacts as prophylaxis for *Neisseria meningitidis.*
* Rifampin
* Ciprofloxacin
* Ceftriaxone
263
*Neisseria meningitidis* is treated with \_\_\_\_\_.
* Ceftriaxone
* Penicillin G
264
Bacteria:
* small gram ⊝ (coccobacillary) rod
* aerosol transmission
* nontypeable (unencapsulated) strains are the most common cause of mucosal infections (otitis media, conjunctivitis, bronchitis) as well as invasive infections since the vaccine for capsular type b was introduced
* produces IgA protease
*Haemophilus influenzae*
265
Bacteria:
* culture on chocolate agar, which contains factors V (NAD+) and X (hematin) for growth;
* can also be grown with *S. aureus*, which provides factor V via RBC hemolysis
*Haemophilus influenzae*
266
Bacteria:
* epiglottitis
* “cherry red” in children
* “thumb sign” on lateral neck x-ray
* meningitis
* otitis media
* pneumonia
*Haemophilus influenzae*
Ha**EMOP**hilus
* **E**piglottitis
* **M**eningitis
* **O**titis media
* **P**neumonia
267
*Haemophilus influenzae* is treated with \_\_\_\_\_.
* Amoxicillin +/− Clavulanate–mucosal infections
* Ceftriaxone–meningitis
* Rifampin–prophylaxis for close contacts
268
Bacteria:
* vaccine contains type b capsular polysaccharide (polyribosylribitol phosphate) conjugated to diphtheria toxoid or other protein
* given between 2 and 18 months of age
*Haemophilus influenzae*
269
Bacteria:
* Gram ⊝
* aerobe
* coccobacillus
* _Virulence Factors_
* Pertussis toxin (disables Gi)
* Adenylate Cyclase toxin (↑ cAMP)
* Tracheal Cytotoxin
* may be mistaken as viral infection due to lymphocytic infiltrate resulting from immune response
*Bordetella pertussis*
270
Stages of Pertussis
* _**C**atarrhal_—low-grade fevers, **C**oryza
* _**P**aroxysmal_—paroxysms of intense cough followed by inspiratory “whoo**P**” (“whooping cough”), posttussive vomiting
* _Convalescent_—gradual recovery of chronic cough
271
Pertussis is prevented by _____ vaccines.
* Tdap
* DTaP
272
Bacteria:
* Gram ⊝ rod
* Gram stains poorly
* seen on silver stain
* grows on charcoal yeast extract medium with iron and cysteine
* detected by presence of antigen in urine
* labs may show hyponatremia
* aerosol transmission
*Legionella pneumophila*
Think of a French **legionnaire** (soldier) with his **silver** helmet, sitting around a **campfire** (**charcoal**) with his **iron** dagger—he is no **sissy** (**cysteine**).
273
*Legionella pneumophila* causes _____ which presents with severe pneumonia (often unilateral and lobar), fever, GI and CNS symptoms. Common in smokers and in chronic lung disease.
Legionnaires’ disease
274
\_\_\_\_\_ is mild flu-like syndrome caused by *Legionella pneumophila*.
Pontiac Fever
275
*Legionella pneumophila* is treated with \_\_\_\_\_.
* Macrolide
* Quinolone
276
Bacteria:
* Gram ⊝ rod
* aerobic
* motile
* Oxidase ⊕
* non-lactose fermenting
* found in water
* grape-like odor
*Pseudomonas aeruginosa*
277
Bacteria:
* mucoid polysaccharide capsule may contribute to chronic pneumonia in cystic fibrosis patients due to biofilm formation
* corneal ulcers/keratitis in contact lens wearers/minor eye trauma.
*Pseudomonas aeruginosa*
278
*Pseudomonas aeruginosa* is associated with \_\_\_\_\_.
**PSEUDOMONAS**:
* **P**neumonia
* **S**epsis
* **E**cthyma gangrenosum
* **U**TIs
* **D**iabetes
* **O**steomyelitis
* **M**ucoid polysaccharide capsule
* **O**titis externa (swimmer’s ear)
* **N**osocomial infections (eg. catheters, equipment)
* **A**ddicts (drug abusers)
* **S**kin infections (eg. hot tub folliculitis, wound infection in burn victims).
279
\_\_\_\_\_ is a rapidly progressive, necrotic cutaneous lesion caused by *Pseudomonas* bacteremia. Typically seen in immunocompromised patients.
Ecthyma Gangrenosum
280
*Pseudomonas aeruginosa* is treated with \_\_\_\_\_.
**CAMPFIRE**:
* **C**arbapenems
* **A**minoglycosides
* **M**onobactams
* **P**olymyxins (eg. polymyxin B, colistin)
* **F**luoroquinolones (eg. ciprofloxacin, levofloxacin)
* Th**IR**d- and fourth-generation cephalosporins (eg. ceftazidime, cefepime)
* **E**xtended-spectrum penicillins (eg. piperacillin, ticarcillin)
281
Bacteria:
* Gram ⊝ rod
* non-lactose fermenting
* Oxidase ⊝
* can invade the GI tract via M cells of Peyer patches
* *Salmonella*
* *Shigella*
282
Bacteria:
* _Reservoir_: humans only
* can disseminate hematogenously
* produces H2S
* has flagella
* _Virulence Factors_
* Endotoxin
* Vi Capsule
* _Infectious Dose_ (ID50)
* High—large inoculum required
* acid-labile (inactivated by gastric acids)
*Salmonella typhi*
283
Bacteria:
* monocytic immune response
* causes constipation, followed by diarrhea
* causes typhoid fever (rose spots on abdomen, constipation, abdominal pain, fever)
* carrier state with gallbladder colonization
* antibiotics prolong duration of fecal excretion
*Salmonella typhi*
284
*Salmonella typhi* vaccines are \_\_\_\_\_.
* Oral vaccine—live attenuated *S. typhi*
* IM vaccine—Vi capsular polysaccharide
285
*Salmonella typhi* is treated with \_\_\_\_\_.
* Ceftriaxone
* Fluoroquinolone
286
Bacteria:
* _Reservoir_: humans and animals
* can disseminate hematogenously
* produces H2S
* has flagella
* _Virulence Factor_: Endotoxin
* _Infectious Dose_ (ID50): High
*Salmonella* spp.
| (except *S. typhi*)
287
Bacteria:
* PMNs in disseminated disease
* causes diarrhea (possibly bloody)
* no vaccine
* poultry, eggs, pets, and turtles are common sources
* gastroenteritis is usually caused by nontyphoidal species
* antibiotics not indicated
* antibiotics prolong duration of fecal excretion
*Salmonella* spp.
| (except *S. typhi*)
288
Bacteria:
* _Reservoir_: humans only
* cell to cell spread
* does not produce H2S
* no flagella
* _Virulence Factor_:
* Endotoxin
* Shiga toxin (Enterotoxin)
* _Infectious Dose_ (ID50):
* Low—very small inoculum required
* acid stable (resistant to gastric acids)
*Shigella*
289
Bacteria:
* PMN infiltration
* causes bloody diarrhea (bacillary dysentery)
* no vaccine
* _Species_ in order of decreasing severity (less toxin produced):
* *S. dysenteriae*
* *S. flexneri*
* *S. boydii*
* *S. sonnei*
* invasion of M cells is key to pathogenicity
* organisms that produce little toxin can cause disease
* antibiotics shorten duration of fecal excretion
*Shigella*
**Four F**’s:
* **F**ingers
* **F**lies
* **F**ood
* **F**eces
290
Bacteria:
* Gram ⊝ rod
* usually transmitted from pet feces (eg. puppies), contaminated milk, or pork
* causes acute diarrhea or pseudoappendicitis (right lower abdominal pain due to mesenteric adenitis and/or terminal ileitis)
*Yersinia enterocolitica*
291
Bacteria:
* MacConkey agar—pink colonies
* EMB agar—purple/black colonies
Lactose-Fermenting Enteric Bacteria
292
Lactose-Fermenting Enteric Bacteria
**Lactose** is **key**. Test with Mac**C**on**KEE**’**S** agar.
* ***C**itrobacter*
* ***K**lebsiella*
* ***E**. coli*
* ***E**nterobacter*
* ***S**erratia* (weak fermenter)
293
*E. coli* produces \_\_\_\_\_, which breaks down lactose into glucose and galactose.
β-galactosidase
294
\_\_\_\_\_ grows colonies with a green sheen.
*E. coli*
295
Bacteria:
* Gram ⊝ rod
* _Virulence Factors_:
* Fimbriae—cystitis and pyelonephritis (P-pili)
* K Capsule—pneumonia, neonatal meningitis
* LPS Endotoxin—septic shock
*Escherichia coli*
296
*E. coli* Strains:
* microbe invades intestinal mucosa and causes necrosis and inflammation
* dysentery
* clinical manifestations similar to *Shigella*
Enteroinvasive *E. coli* (EIEC)
297
*E. coli* Strains:
* produces heat-labile and heat-stable enterotoxins
* no inflammation or invasion
* Traveler’s Diarrhea (watery)
Enterotoxigenic *E. coli* (ETEC)
E**T**EC = **T**raveler’s Diarrhea
298
*E. coli* Strains:
* no toxin produced
* adheres to apical surface
* flattens villi
* prevents absorption
* diarrhea, usually in children
Enteropathogenic *E. coli* (EPEC)
E**P**EC = **P**ediatrics
299
*E. coli* Strains:
* O157:H7 is most common serotype in US
* transmitted via undercooked meat, raw leafy vegetables
* Shiga-like toxin causes Hemolytic-Uremic
* Syndrome
* dysentery (toxin alone causes necrosis and inflammation)
* does not ferment Sorbitol (vs. other *E. coli*)
Enterohemorrhagic *E. coli* (EHEC)
E**H**EC = **H**emorrhagic, **H**amburgers, **H**US
300
EHEC produces Shiga-like toxin which causes \_\_\_\_\_: triad of anemia, thrombocytopenia, and acute renal failure due to microthrombi forming on damaged endothelium → mechanical hemolysis (with schistocytes on peripheral blood smear), platelet consumption, and ↓ renal blood flow.
Hemolytic-Uremic Syndrome (HUS)
301
Bacteria:
* Gram ⊝ rod
* intestinal flora that causes lobar pneumonia in alcoholics and diabetics when aspirated
* very mucoid colonies caused by abundant polysaccharide capsules
* dark red “currant jelly” sputum (blood/mucus)
* nosocomial UTI
* associated with evolution of multidrug resistance (MDR)
*Klebsiella*
**5 A**’s of *Klebsiell**A***:
* **A**spiration pneumonia
* **A**bscess in lungs and liver
* **A**lcoholics
* Di**A**betics
* “Curr**A**nt jelly” sputum
302
Bacteria:
* Gram ⊝
* comma or S shaped (with polar flagella)
* Oxidase ⊕
* grows at 42°C
* major cause of bloody diarrhea, especially in children
* fecal-oral transmission through person-to-person contact or via ingestion of undercooked contaminated poultry or meat, unpasteurized milk
* contact with infected animals (dogs, cats, pigs) is a risk factor
* common antecedent to Guillain-Barré syndrome and reactive arthritis
*Campylobacter jejuni*
**Camp**ylobacter likes the hot **camp**fire.
303
Bacteria:
* Gram ⊝
* flagellated
* comma shaped
* Oxidase ⊕
* grows in alkaline media
* endemic to developing countries
* produces profuse rice-water diarrhea via enterotoxin that permanently activates Gs, ↑ cAMP
* sensitive to stomach acid (acid labile)
* requires large inoculum (high ID50) unless host has ↓ gastric acidity
* transmitted via ingestion of contaminated water or uncooked food (eg. raw shellfish)
* treat promptly with oral rehydration solution
*Vibrio cholerae*
304
Bacteria:
* Gram ⊝ rod
* curved
* flagellated (motile)
* _Triple ⊕_:
* Catalase ⊕
* Oxidase ⊕
* Urease ⊕
* urea breath test or fecal antigen test are used for diagnosis
* Urease produces ammonia, creating an alkaline environment, which helps survival in acidic mucosa
* colonizes mainly antrum of stomach
* causes gastritis and peptic ulcers (especially duodenal)
* risk factor for pepti ulcer disease, gastric adenocarcinoma, and MALT lymphoma
*Helicobacter pylori*
305
*Helicobacter pylori* is treated with triple therapy which includes \_\_\_\_\_.
**A**ntibiotics **C**ure **P**ylori.
* **A**moxicillin (Metronidazole for Penicillin allergy)
* **C**larithromycin
* **P**roton Pump Inhibitor
306
Bacteria:
* spiral-shaped
* axial filaments
Spirochetes
307
Spirochetes
**BLT**
* ***B**orrelia* (big size)—***B**orrelia* is **B**ig
* ***L**eptospira*
* ***T**reponema*
308
Among the spirochetes, only _____ can be visualized using aniline dyes (Wright or Giemsa stain) in light microscopy due to size.
*Borrelia*
309
*Treponema* is visualized by \_\_\_\_\_.
* Dark-Field Microscopy
* Direct Fluorescent Antibody (DFA) Microscopy
310
Bacteria:
* Lyme disease
* transmitted by the *Ixodes* deer tick (also
* vector for *Anaplasma* spp. and protozoa *Babesia*)
* natural reservoir is the mouse (and important to tick life cycle)
* common in northeastern US
*Borrelia burgdorferi*
311
Lyme Disease Symptoms
A Key **Lyme** pie to the **FACE**:
* **F**acial nerve palsy (typically bilateral)
* **A**rthritis
* **C**ardiac block
* **E**rythema migrans
312
Stages of Lyme Disease
* Stage 1—_Early Localized_: erythema migrans (typical “bulls-eye” configuration is pathognomonic but not always present), flu‑like symptoms
* Stage 2—_Early Disseminated_: secondary lesions, carditis, AV block, facial nerve (Bell) palsy, migratory myalgias/transient arthritis
* Stage 3—_Late Disseminated_: encephalopathy, chronic arthritis
313
Lyme disease is treated with \_\_\_\_\_.
* Doxycycline (1st line)
* Amoxicillin
* Cefuroxime (pregnant women and children)
314
Bacteria:
* spirochete
* hook-shaped ends
* found in water contaminated with animal urine
*Leptospira interrogans*
315
\_\_\_\_\_ presents with flu-like symptoms, myalgias (classically of calves), jaundice, photophobia with conjunctival suffusion (erythema without exudate). Prevalent among surfers and in tropics (eg. Hawaii).
Leptospirosis
316
\_\_\_\_\_ is the severe form of _____ with jaundice and azotemia from liver and kidney dysfunction, fever, hemorrhage and anemia.
Weil Disease
(Icterohemorrhagic Leptospirosis)
317
Bacteria:
* spirochete
* causes syphilis
*Treponema pallidum*
318
Syphilis:
* localized disease presenting with painless chancre
* dark-field microscopy is used to visualize treponemes in fluid from chancre
* VDRL ⊕ in ~ 80%
Primary Syphilis
319
Syphilis:
* disseminated disease with constitutional symptoms
* maculopapular rash C (including palms and soles)
* condylomata lata (smooth, painless, wart-like white lesions on genitals)
* lymphadenopathy
* patchy hair loss
* confirmable with dark-field microscopy
* _Serologic Testing_:
* VDRL/RPR—nonspecific
* FTA-ABS—specific, confirmatory
* latent syphilis (⊕ serology without symptoms) may follow
Secondary Syphilis
**S**econdary = **S**ystemic
320
Syphilis:
* gummas (chronic granulomas)
* aortitis (vasa vasorum destruction)
* neurosyphilis (tabes dorsalis, “general paresis”)
* Argyll Robertson pupil (constricts with accommodation but is not reactive to light; also called “prostitute’s pupil” since it accommodates but does not react)
* **_Sign_**s:
* broad-based ataxia
* ⊕ Romberg
* Charcot joint
* stroke without hypertension
* _Neurosyphilis_: test spinal fluid with VDRL, FTA-ABS, and PCR.
Tertiary Syphilis
321
Syphilis:
* rhagades (linear scars at angle of mouth)
* snuffles (nasal discharge)
saddle nose
* notched (Hutchinson) teeth
* mulberry molars
* short maxilla
* saber shins
* CN VIII deafness
Congenital Syphilis
322
To prevent congenital syphilis, treat the mother early in pregnancy, as placental transmission typically occurs after the \_\_\_\_\_.
1st Trimester
323
VDRL detects nonspecific antibody that
reacts with beef cardiolipin. Quantitative,
inexpensive, and widely available test for
syphilis (sensitive but not specific).
324
VDRL False Positives
False-**P**ositive results on **VDRL** with:
* **P**regnancy
* **V**iral Infection (eg. EBV, Hepatitis)
* **D**rugs
* **R**heumatic Fever
* **L**upus and **L**eprosy
325
\_\_\_\_\_ is a flu-like syndrome (fever, chills, headache, myalgia) after antibiotics are started; due to killed bacteria (usually spirochetes) releasing toxins.
Jarisch-Herxheimer Reaction
326
Bacteria:
* Gram-variable rod
* pleomorphic
* bacterial vaginosis
* presents as a gray vaginal discharge with a fishy smell
* nonpainful (vs. vaginitis)
* associated with sexual activity, but not sexually transmitted
* bacterial vaginosis is also characterized by overgrowth of certain anaerobic bacteria in vagina
* Clue Cells (vaginal epithelial cells covered with bacteria) have stippled appearance along outer margin
*Gardnerella vaginalis*
I don’t have a **clue** why I smell **fish** in the **vegetable** (**vagina**) **garden**!
327
In \_\_\_\_\_, mixing *Gardnerella vaginalis* discharge with 10% KOH enhances its fishy odor.
Amine Whiff Test
328
*Gardnerella vaginalis* is treated with \_\_\_\_\_.
* Metronidazole
* Clindamycin
329
Bacteria:
* cannot make their own ATP
* obligate intracellular organisms
* cause mucosal infections
Chlamydiae
*Chlamys* = cloak (intracellular)
330
2 Forms of Chlamydiae
* **E**lementary Body
* small, dense
* “**E**nfectious”
* **E**nters cell via **E**ndocytosis
* transforms into reticulate body
* **R**eticulate Body
* **R**eplicates in cell by fission
* **R**eorganizes into elementary bodies
331
Chlamydiae:
* reactive arthritis (Reiter syndrome)
* neonatal and follicular adult conjunctivitis
* nongonococcal urethritis
* PID
*Chlamydia trachomatis*
332
Chlamydiae:
* atypical pneumonia
* transmitted by aerosol
* Chlamydophila pneumoniae
* Chlamydophila psittaci
333
Chlamydiae:
* avian reservoir (parrots)
* atypical pneumonia
*Chlamydophila psittaci*
334
Chlamydia is diagnosed with \_\_\_\_\_.
PCR
335
Cytoplasmic inclusions (reticulate bodies) of Chlamydia are seen on \_\_\_\_\_.
* Giemsa
* Fluorescent Antibody-Stained Smear
336
The chlamydial cell wall lacks classic peptidoglycan (due to reduced muramic acid), rendering _____ ineffective.
β-lactam antibiotics
337
Chlamydia is treated with \_\_\_\_\_.
* Azithromycin (favored because of one-time treatment)
* Doxycycline (+ Ceftriaxone for possible concomitant gonorrhea)
338
*Chlamydia trachomatis* Serotypes:
* found in Africa
* cause blindness due to follicular conjunctivitis
* chronic infection
Types A, B, and C
**ABC** = **A**frica, **B**lindness, **C**hronic infection
339
*Chlamydia trachomatis* Serotypes:
* urethritis/PID
* ectopic pregnancy
* neonatal pneumonia (staccato cough) with eosinophilia
* neonatal conjunctivitis (1–2 weeks after birth)
* neonatal disease can be acquired during passage through infected birth canal
Types D–K
340
*Chlamydia trachomatis* Serotypes:
* Lymphogranuloma Venereum
* small, painless ulcers on genitals → swollen, painful inguinal lymph nodes that ulcerate (buboes)
* treated with Doxycycline
Types L1, L2, and L3
341
*Chlamydia trachomatis* causes _____ which presents with small, painless ulcers on genitals → swollen, painful inguinal lymph nodes that ulcerate (buboes)
Lymphogranuloma Venereum
342
\_\_\_\_\_ is infectious disease transmitted between animals and humans.
Zoonosis
343
Zoonotic Bacteria:
* Anaplasmosis
* *Ixodes* ticks (live on deer and mice)
*Anaplasma* spp.
344
Zoonotic Bacteria:
* Cat Scratch Disease
* Bacillary Angiomatosis
*Bartonella* spp.
345
Zoonotic Bacteria:
* Lyme disease
* *Ixodes* ticks (live on deer and mice)
*Borrelia burgdorferi*
346
Zoonotic Bacteria:
* Relapsing Fever
* louse (recurrent due to variable surfac antigens)
*Borrelia recurrentis*
347
Zoonotic Bacteria:
* Brucellosis
* Undulant Fever
* unpasteurized dairy
*Brucella* spp.
348
Zoonotic Bacteria:
* bloody diarrhea
* feces from infected pets/animals
* contaminated meats/foods/hands
*Campylobacter*
349
Zoonotic Bacteria:
* Psittacosis
* parrots, other birds
*Chlamydophila psittaci*
350
Zoonotic Bacteria:
* Q Fever
* aerosols of cattle/sheep amniotic fluid
*Coxiella burnetii*
351
Zoonotic Bacteria:
* Ehrlichiosis
* *Amblyomma* (lone star tick)
*Ehrlichia chaffeensis*
352
Zoonotic Bacteria:
* Tularemia
* ticks, rabbits, deer flies
*Francisella tularensis*
353
Zoonotic Bacteria:
* Leptospirosis
* animal urine in water
* recreational water use
*Leptospira* spp.
354
Zoonotic Bacteria:
* Leprosy
* lepromatous form is contagious
* armadillo (rare)
*Mycobacterium leprae*
355
Zoonotic Bacteria:
* Cellulitis
* Osteomyelitis
* animal bite, cats, dogs
*Pasteurella multocida*
356
Zoonotic Bacteria:
* epidemic typhus
* human to human via human body louse
*Rickettsia prowazekii*
357
Zoonotic Bacteria:
* Rocky Mountain Spotted Fever
* *Dermacentor* (dog tick)
*Rickettsia rickettsii*
358
Zoonotic Bacteria:
* endemic typhus
* fleas
*Rickettsia typhi*
359
Zoonotic Bacteria:
* diarrhea (which may be bloody)
* vomiting
* fever
* abdominal cramps
* reptiles and poultry
*Salmonella* spp.
| (except *S. typhi*)
360
Zoonotic Bacteria:
* Plague
* fleas (rats and prairie dogs are reservoirs)
*Yersinia pestis*
361
Rickettsial diseases and vector-borne illnesses are treated with \_\_\_\_\_.
* Doxycycline (caution during pregnancy)
* Chloramphenicol (alternative)
362
Common Rashes:
* *Rickettsia rickettsii*
* vector is tick
* despite its name, disease occurs primarily in the South Atlantic states, especially North Carolina
* rash typically starts at wrists and ankles and then spreads to trunk, palms, and soles
* _Classic Triad_:
* headache
* fever
* rash (vasculitis)
Rocky Mountain Spotted Fever
You drive **CARS** using your **palms** and **soles**.
**Palms** and **Soles** Rash:
* **C**oxsackievirus **A** Infection (Hand, Foot, and Mouth Disease)
* **R**ocky Mountain Spotted Fever
* 2° **S**yphilis.
363
Common Rashes:
* **_En_**demic (fleas)—*R. typhi*
* **_Epi_**demic (human body louse)—*R. prowazekii*
* rash starts centrally and spreads out, sparing palms and soles.
Typhus
***R**ickettsii* on the w**R**ists
***T**yphus* on the **T**runk
364
Rare Rashes:
* *Ehrlichia*
* vector is tick
* monocytes with morulae (mulberry-like inclusions) in cytoplasm
Ehrlichiosis
**MEGA berry**:
* **M**onocytes = **E**hrlichiosis
* **G**ranulocytes = **A**naplasmosis
365
Rare Rashes:
* *Anaplasma*
* vector is tick
* granulocytes with morulae (mulberry-like inclusions) in cytoplasm
Anaplasmosis
**MEGA berry**:
* **M**onocytes = **E**hrlichiosis
* **G**ranulocytes = **A**naplasmosis
366
Rare Rashes:
* *Coxiella burnetii*—not in the *Rickettsia* genus, but closely related
* no arthropod vector
* spores are inhaled as aerosols from cattle/sheep amniotic fluid
* pneumonia
* common cause of culture ⊝ endocarditis
Q fever
**Q** fever is **Q**ueer because it has no rash or vector and its causative organism can survive outside in its endospore form.
367
Bacteria:
* pleomorphic
* no cell wall
* not seen on Gram stain
* grown on Eaton agar
* classic cause of atypical “walking” pneumonia (insidious onset, headache, nonproductive cough, patchy or diffuse interstitial infiltrate)
* CXR looks worse than patient
* high titer of cold agglutinins (IgM) which can agglutinate RBCs
* bacterial membrane contains sterols for stability
* pneumonia is more common in patients \< 30 years old
* frequent outbreaks in military recruits and prisons
* Mycoplasma pneumoniae*
* Mycoplasma* gets **cold** without a **coat** (cell wall).
368
*Mycoplasma pneumoniae* is treated with \_\_\_\_\_.
* Macrolides
* Doxycycline
* Fluoroquinolone
\*Penicillin ineffective since *Mycoplasma* have no cell wall
369
Mycoses:
* pneumonia
* can disseminate
* caused by dimorphic fungi:
* cold (20°C) = mold
* heat (37°C) = yeast
* only exception is *Coccidioides*, which is a spherule (not yeast) in tissue
* can form granulomas (like TB)
* cannot be transmitted person-to-person (unlike TB)
Systemic Mycoses
370
Systemic mycoses are treated with \_\_\_\_.
* Local Infection
* Fluconazole
* Itraconazole
* Systemic Infection
* Amphotericin B
371
Systemic Mycoses
* *Histoplasmosis*
* *Blastomycosis*
* *Coccidioidomycosis*
* *Paracoccidioidomycosis*
372
Systemic Mycoses:
* Mississippi and Ohio River Valleys
* macrophage filled with mycoses (smaller than RBC)
* palatal/tongue ulcers
* splenomegaly
* bird (eg. starlings) or bat droppings
* diagnosis via urine/serum antigen
Histoplasmosis
**H**isto **H**ides (within macrophages)
373
Systemic Mycoses:
* Eastern and Central US
* broad-based budding (same size as RBC)
* inflammatory lung disease
* can disseminate to skin/bone
* verrucous skin lesions can simulate SCC
* forms granulomatous nodules
Blastomycosis
**B**lasto **B**uds **B**roadly
374
Systemic Mycoses:
* Southwestern US, California
* spherule (much larger than RBC) filled with endospores
* disseminates to skin/bone
* erythema nodosum (desert bumps) or multiforme
* arthralgias (desert rheumatism)
* can cause meningitis
Coccidioidomycosis
375
Systemic Mycoses:
* Latin America
* budding yeast with “captain’s wheel” formation (much larger than RBC)
* similar to blastomycosis
* males \> females
Paracoccidioidomycosis
**Para**coccidio **para**sails with the **captain’s wheel** all the way to **Latin America**.
376
Cutaneous Mycoses
* Tinea (Dermatophytes)
* Tinea Capitis
* Tinea Corporis
* Tinea Cruris
* Tinea Pedis
* Tinea Unguium
* Tinea (Pityriasis) Versicolor
377
Cutaneous Mycoses:
* clinical name for dermatophyte (cutaneous fungal) infections
* branching septate hyphae visible on KOH preparation with blue fungal stain
* associated with pruritus
Tinea
378
Dermatophytes
* *Microsporum*
* *Trichophyton*
* *Epidermophyton*
379
Tinea
* Tinea Capitis
* Tinea Corporis
* Tinea Cruris
* Tinea Pedis
* Tinea Unguium
380
Cutaneous Mycoses:
* occurs on head and scalp
* associated with lymphadenopathy, alopecia, and scaling
Tinea Capitis
381
Cutaneous Mycoses:
* occurs on torso
* characterized by erythematous scaling rings (“ringworm”) and central clearing
* can be acquired from contact with an infected cat or dog
Tinea Corporis
382
Cutaneous Mycoses:
* occurs in inguinal area
* often does not show the central clearing seen in tinea corporis
Tinea Cruris
383
Cutaneous Mycoses:
* occurs on feet
* _Three Varieties_:
* Interdigital—most common
* Moccasin distribution
* Vesicular type
Tinea Pedis
384
Cutaneous Mycoses:
* occurs on nails
* Onychomycosis
Tinea Unguium
385
Cutaneous Mycoses:
* caused by *Malassezia* spp. (*Pityrosporum* spp.), a yeast-like fungus (not a dermatophyte despite being called tinea)
* degradation of lipids produces acids that damage melanocytes and cause hypopigmented, hyperpigmented, and/or pink patches
* less pruritic than dermatophytes
* can occur any time of year, but more common in summer (hot, humid weather)
* “spaghetti and meatballs” appearance on microscopy
Tinea (Pityriasis) Versicolor
386
Tinea (Pityriasis) Versicolor is treated with \_\_\_\_\_.
* Selenium Sulfide
* topical and/or oral antifungal medications
387
Opportunistic Fungal Infections
* *Candida albicans*
* *Aspergillus fumigatus*
* *Cryptococcus neoformans*
* *Mucor* spp.
* *Rhizopus* spp.
388
Opportunistic Fungal Infections:
* dimorphic
* pseudohyphae and budding yeasts at 20°C
* germ tubes a 37°C
* systemic or superficial fungal infection
* oral and esophageal thrush in immunocompromised (neonates, steroids, diabetes, AIDS)
* vulvovaginitis (diabetes, use of antibiotics)
* diaper rash
* endocarditis (IV drug users)
* disseminated candidiasis (especially in neutropenic patients)
* chronic mucocutaneous \_\_\_\_\_
*Candida albicans*
389
*Candida albicans* is treated with \_\_\_\_\_.
* Vaginal
* Oral Fluconazole
* Topical Azole
* Oral/Esophageal
* Nystatin
* Fluconazole
* Echinocandins
* Systemic
* Fluconazole
* Echinocandins
* Amphotericin B
390
Opportunistic Fungal Infections:
* monomorphic septate hyphae
* branch at 45° acute angle
* invasive aspergillosis in immunocompromised patients and in neutrophil dysfunction (eg. chronic granulomatous disease)
* aspergillomas in pre-existing lung cavities, especially after TB infection
* some species produce Aflatoxins (associated with hepatocellular carcinoma)
*Aspergillus fumigatus*
***A**spergillus*, **A**cute **A**ngle, **A**flatoxins
391
\_\_\_\_\_ is a hypersensitivity response associated with asthma and cystic fibrosis; may cause bronchiectasis and eosinophilia.
Allergic Bronchopulmonary Aspergillosis (ABPA)
392
Opportunistic Fungal Infections:
* 5–10 μm with narrow budding
* heavily encapsulated yeast
* not dimorphic
* found in soil and pigeon droppings
* acquired through inhalation with hematogenous dissemination to meninges
* culture on Sabouraud agar
* highlighted with India ink (clear halo) and mucicarmine (red inner capsule)
* latex agglutination test detects polysaccharide capsular antigen and is more specific
* causes disseminated infection, meningitis, and encephalitis (“soap bubble” lesions in brain), primarily in immunocompromised
*Cryptococcus neoformans*
393
*Cryptococcus neoformans* is treated with \_\_\_\_\_.
Amphotericin B + Flucytosine followed by Fuconazole for cryptococcal meningitis
394
Opportunistic Fungal Infections:
* irregular, broad, nonseptate hyphae
* branching at wide angles
* mucormycosis mostly in ketoacidotic diabetic and/or neutropenic patients (eg. leukemia)
* inhalation of spores → fungi proliferate in blood vessel walls, penetrate cribriform plate, and enter brain
* rhinocerebral, frontal lobe abscess
* cavernous sinus thrombosis
* headache, facial pain, black necrotic eschar on face
* may have cranial nerve involvement
*Mucor* and *Rhizopus* spp.
395
*Mucor* and *Rhizopus* spp. are treated with \_\_\_\_\_.
* surgical debridement
* Amphotericin B
* Isavuconazole
396
Mycoses:
* causes _____ pneumonia (PCP), a diffuse interstitial pneumonia
* yeast-like fungus (originally classified as protozoan)
* most infections are asymptomatic
* immunosuppression (eg. AIDS) predisposes to disease
* diffuse, bilateral ground-glass opacities on CXR/CT, with pneumatoceles
* diagnosed by lung biopsy or lavage
* disc-shaped yeast seen on methenamine silver stain of lung tissue
*Pneumocystis jirovecii*
397
*Pneumocystis jirovecii* is treated with \_\_\_\_\_.
* TMP-SMX
* Pentamidine
* Atovaquone
* Dapsone (prophylaxis only)
* start prophylaxis when CD4+ count drops to \< 200 cells/mm3 in HIV patients
398
Mycoses:
* Sporotrichosis
* dimorphic, cigar-shaped budding yeast that grows in branching hyphae with rosettes of conidia
* lives on vegetation
* when spores are traumatically introduced into the skin, typically by a thorn (“rose gardener’s disease”), causes local pustule or ulcer with nodules along draining lymphatics (ascending lymphangitis)
* disseminated disease possible in immunocompromised host
*Sporothrix schenckii*
A **rose gardener** smokes **cigars** and **pot**.
399
*Sporothrix schenckii* is treated with \_\_\_\_\_.
* Itraconazole
* Potassium Iodide
A **rose gardener** smokes **cigars** and **pot**.
400
Protozoa:
Gastrointestinal Infections
* *Giardia lamblia*
* *Entamoeba histolytica*
* *Cryptosporidium*
401
Protozoa:
* bloating, flatulence, foul-smelling, fatty diarrhea
* (often seen in campers/hikers)
* transmitted through cysts in water
* diagnosed with multinucleated trophozoites/cysts in stool or antigen detection
*Giardia lamblia*
**fat**ty stools of ***Giardia*** = **fat**-rich **Ghirardelli** chocolates
402
\_\_\_\_\_ causes bloating, flatulence, and foul-smelling, fatty diarrhea (often seen in campers/hikers).
Giardiasis
**fat**ty stools of **Giardia** = **fat**-rich **Ghirardelli** chocolates
403
*Giardia lamblia* is treated with \_\_\_\_\_.
Metronidazole
404
Protozoa:
* bloody diarrhea (dysentery)
* liver abscess (“anchovy paste” exudate)
* RUQ pain
* histology of colon biopsy shows flask-shaped ulcers
* transmitted through cysts in water
* diagnosed with serology, antigen testing, and/or trophozoites (with engulfed RBCs in the cytoplasm) or cysts with up to 4 nuclei in stool
*Entamoeba histolytica*
**E**ntamoeba **E**ats **E**rythrocytes
405
\_\_\_\_\_ causes bloody diarrhea (dysentery), liver abscess (“anchovy paste” exudate), and RUQ pain. Histology of colon biopsy shows flask-shaped ulcers.
Amebiasis
406
*Entamoeba histolytica* is treated with \_\_\_\_\_.
* Metronidazole
* Paromomycin—asymptomatic cyst passers
* Iodoquinol—asymptomatic cyst passers
407
Protozoa:
* severe diarrhea in AIDS
* mild disease (watery diarrhea) in immunocompetent hosts
* transmitted through oocysts in water
* diagnosed with oocysts on acid-fast stain or antigen detection
*Cryptosporidium*
408
*Cryptosporidium* is treated with \_\_\_\_\_.
* Nitazoxanide—immunocompetent hosts
* prevention—filtering city water supplies
409
Protozoa:
CNS Infections
* *Toxoplasma gondii*
* *Naegleria fowleri*
* *Trypanosoma brucei*
410
Protozoa:
* Imononucleosis-like symptoms
* ⊝ heterophile antibody test
* reactivation in AIDS → brain abscesses usually seen as multiple ring-enhancing lesions on MRI
* congenital infection prests with the classic triad of chorioretinitis, hydrocephalus, and intracranial calcifications
* transmitted through cysts in meat (most common) or oocysts in cat feces
* crosses the placenta (pregnant women should avoid cats)
* diagnosed with serology or biopsy (tachyzoite)
*Toxoplasma gondii*
411
*Toxoplasma gondii* is treated with \_\_\_\_\_.
Sulfadiazine + Pyrimethamine
412
Protozoa:
* rapidly fatal meningoencephalitis
* swimming in warm freshwater ↑ risk
* enters via cribriform plate
* diagnosed with amoebas in CSF
*Naegleria fowleri*
A **Nalgene** bottle is filled with **fresh water**.
413
*Naegleria fowleri* is treated with \_\_\_\_\_.
Amphotericin B—has been effective for a few survivors
414
Protozoa:
* enlarged lymph nodes
* recurring fever (due to antigenic variation)
* somnolence
* coma
* transmitted through the Tsetse fly—painful bite
* diagnosed with trypomastigote in blood smear
*Trypanosoma brucei*
415
*Trypanosoma brucei* causes _____ which presents with enlarged lymph nodes, recurring fever (due to antigenic variation), somnolence, and coma.
African Sleeping Sickness
416
*Trypanosoma brucei* is treated with \_\_\_\_\_.
* Suramin—bloodborne disease
* Melarsoprol—CNS penetration
I **sur**e am **mel**low when I’m **sleep**ing.
417
Protozoa:
Hematologic Infections
* *Plasmodium*
* *P. vivax*
* *P. ovale*
* *P. falciparum*
* *P. malariae*
* *Babesia*
418
Protozoa:
* Malaria—fever, headache, anemia, splenomegaly
* transmitted through the *Anopheles* mosquito
* diagnosed with blood smear
* trophozoite ring form within RBC
* schizont containing merozoites
*Plasmodium*
419
*Plasmodium*:
* 48-hr cycle (tertian; includes fever on first day and third day, thus fevers are actually 48 hr apart)
* dormant form (hypnozoite) in liver
* red granules (Schüffner stippling) throughout RBC cytoplasm
*P. vivax/ovale*
420
*Plasmodium*:
* severe
* irregular fever patterns
* parasitized RBCs occlude capillaries in brain (cerebral malaria), kidneys, and lungs
*P. falciparum*
421
*Plasmodium*:
72-hr cycle (quartan)
*P. malariae*
422
*Plasmodium* is treated with \_\_\_\_\_.
* Sensitive Species
* Chloroquine—blocks *Plasmodium* heme polymerase
* Resistant Species
* Mefloquine
* Atovaquone/Proguanil
* Life-Threatening
* IV Quinidine
* IV Artesunate—test for G6PD deficiency
* For *P. vivax/ovale*
* add Primaquine for hypnozoite—test for G6PD deficiency
423
Protozoa:
* fever and hemolytic anemia
* predominantly in northeastern US
* asplenia ↑ risk of severe disease
* transmitted through the *Ixodes* tick (same as *Borrelia burgdorferi* of Lyme disease; may often coinfect humans)
* diagnosed with blood smear or PCR
* ring form
* “Maltese cross”
*Babesia*
424
*Babesia* is treated with \_\_\_\_\_.
Atovaquone + Azithromycin
425
Protozoa:
Visceral Infections
* *Trypanosoma cruzi*
* *Leishmania donovani*
426
Protozoa:
* Chagas disease—dilated cardiomyopathy with apical atrophy, megacolon, megaesophagus
* predominantly in South America
* unilateral periorbital swelling (Romaña sign) characteristic of acute stage
* transmitted through the Triatomine (“kissing”) bug, a type of reduviid bug, deposits feces in a painless bite (much like a kiss)
* diagnosed with Trypomastigote in blood smear
*Trypanosoma cruzi*
427
*Trypanosoma cruzi* is treated with \_\_\_\_\_.
* Benznidazole
* Nifurtimox
I'm **cruzi**ng in my **Benz**, with a **fur** coat on.
428
Protozoa:
* Visceral (kala-azar)—spiking fevers, hepatosplenomegaly, pancytopenia
* Cutaneous—skin ulcers
* transmitted through the sandfly
* macrophages containing amastigotes
*Leishmania donovani*
429
*Leishmania donovani* is treated with \_\_\_\_\_.
* Amphotericin B
* Sodium Stibogluconate
430
Protozoa:
Sexually Transmitted Infections
*Trichomonas vaginalis*
431
Protozoa:
* Vaginitis—foul-smelling greenish discharge, itching and burning
* transmitted through sexual contact (cannot exist outside human because it cannot form cysts)
* diagnosed with trophozoites (motile) on wet mount
* “strawberry cervix”
*Trichomonas vaginalis*
432
*Trichomonas vaginalis* is treated with \_\_\_\_\_.
Metronidazole for patient and partner (prophylaxis)
433
Nematodes (Roundworms):
Ingested
You’ll get sick if you **EATTT** these!
* **E**nterobius
* **A**scaris
* **T**oxocara
* **T**richinella
* **T**richuris
434
Nematodes (Roundworms):
Cutaneous
These get into your feet from the **SAN**d.
* **S**trongyloides
* **A**ncylostoma
* **N**ecator
435
Nematodes (Roundworms):
Bites
Lay **LOW** to avoid getting bitten.
* **L**oa loa
* **O**nchocerca volvulus
* **W**uchereria bancrofti
436
Nematodes (Roundworms):
Intestinal
* *Enterobius vermicularis* (pinworm)
* *Ascaris lumbricoides* (giant roundworm)
* *Strongyloides stercoralis* (threadworm)
* *Ancylostoma duodenale* (hookworms)
* *Necator americanus* (hookworms)
* *Trichinella spiralis*
* *Trichuris trichiura* (whipworm)
437
Nematodes (Roundworms):
* causes anal pruritus
* diagnosed by seeing egg via the tape test
* fecal-oral route
*Enterobius vermicularis* (pinworm)
438
*Enterobius vermicularis* (pinworm) is treated with \_\_\_\_\_.
* Pyrantel Pamoate
* Bendazoles
439
Nematodes (Roundworms):
* may cause obstruction at ileocecal valve, biliary obstruction, and intestinal perforation
* migrates from nose/mouth
* fecal-oral route
* knobby-coated, oval eggs seen in feces under microscope
*Ascaris lumbricoides* (giant roundworm)
440
*Ascaris lumbricoides* (giant roundworm) is treated with \_\_\_\_\_.
Bendazoles
441
Nematodes (Roundworms):
* Autoinfection—rarely, some larvae may penetrate the intestinal wall to enter the bloodstream without leaving the body
* larvae in soil penetrate skin
* rhabditiform larvae seen in feces under microscope
*Strongyloides stercoralis* (threadworm)
442
*Strongyloides stercoralis* (threadworm) is treated with \_\_\_\_\_.
* Ivermectin
* Bendazoles
443
Nematodes (Roundworms):
* Cutaneous Larva Migrans—pruritic, serpiginous rash from walking barefoot on contaminated beach
* cause anemia by sucking blood from intestinal wall
* larvae penetrate skin
* *Ancylostoma* *duodenale*
* *Necator* *americanus*
\*hookworms
444
*Ancylostoma duodenale* and *Necator americanus* (hookworms) are treated with \_\_\_\_\_.
* Bendazoles
* Pyrantel Pamoate
445
Nematodes (Roundworms):
* larvae enter bloodstream, encyst in striated muscle → muscle inflammation
* causes fever, vomiting, nausea, periorbital edema, and myalgia
* undercooked meat (especially pork)
* fecal-oral (less likely)
*Trichinella spiralis*
446
*Trichinella spiralis* is treated with \_\_\_\_\_.
Bendazoles
447
Nematodes (Roundworms):
* often asymptomatic
* loose stools
* anemia
* rectal prolapse in children (heavy infection)
* fecal-oral route
*Trichuris trichiura* (whipworm)
448
*Trichuris trichiura* (whipworm) is treated with \_\_\_\_\_.
Bendazoles
449
Nematodes (Roundworms):
Tissue
* *Toxocara canis*
* *Onchocerca volvulus*
* *Loa loa*
* *Wuchereria bancrofti*
450
Nematodes (Roundworms):
* Visceral Larva Migrans—nematode migrate to blood through intestinal wall → inflammation and damage
* often affects heart (myocarditis), liver, eyes (visual impairment, blindness), and CNS (seizures, coma)
* fecal-oral route
*Toxocara canis*
451
*Toxocara canis* is treated with \_\_\_\_\_.
Bendazoles
452
Nematodes (Roundworms):
* skin changes, loss of elastic fibers, and river blindness (black flies, black skin nodules, “black sight”)
* allergic reaction to microfilaria possible
* transmitted through the female blackfly
*Onchocerca volvulus*
453
*Onchocerca volvulus* is treated with \_\_\_\_\_.
Ivermectin
**Iver**mectin for R**iver** Blindness
454
Nematodes (Roundworms):
* swelling in ski
* worm in conjunctiva
* transmitted through the deer fly, horse fly, and mango fly
*Loa loa*
455
*Loa loa* is treated with \_\_\_\_\_.
Diethylcarbamazine
456
Nematodes (Roundworms):
* Lymphatic Filariasis (Elephantiasis)—worms invade lymph nodes → inflammation → lymphedema
* symptom onset after 9 mo.–1 yr.
* transmitted through the female mosquito
*Wuchereria bancrofti*
457
*Wuchereria bancrofti* is treated with \_\_\_\_\_.
Diethylcarbamazine
458
Cestodes (Tapeworms)
* *Taenia solium*
* *Diphyllobothrium* *latum*
* *Echinococcus* *granulosus*
459
Cestodes (Tapeworms):
* Intestinal Tapeworm—ingestion of larvae encysted in undercooked pork
* Cysticercosis
* Neurocysticercosis (cystic CNS lesions, seizures)
* ingestion of eggs in food contaminated with human feces
*Taenia solium*
460
*Taenia solium* is treated with \_\_\_\_\_.
* Praziquantel
* Albendazole for neurocysticercosis
461
Cestodes (Tapeworms):
* Vitamin B12 deficiency (tapeworm competes for B12 in intestine) → megaloblastic anemia
* ingestion of larvae in raw freshwater fish
*Diphyllobothrium latum*
462
*Diphyllobothrium latum* is treated with \_\_\_\_\_.
Praziquantel
463
Cestodes (Tapeworms):
* Hydatid cysts (“eggshell calcification”) in liver
* cyst rupture can cause anaphylaxis
* ingestion of eggs in food contaminated with dog feces
* sheep are an intermediate host
*Echinococcus granulosus*
464
Echinococcus granulosus is treated with \_\_\_\_\_.
Albendazole
465
Trematodes (Flukes)
* *Schistosoma*
* *Clonorchis sinensis*
466
Trematodes (Flukes):
* *S. mansoni*
* egg with lateral spine
* liver and spleen enlargement fibrosis, inflammation, portal hypertension
* *S. haematobium*
* **chronic infection
* egg with terminal spine
* can lead to squamous cell carcinoma of the bladder (painless hematuria) and pulmonary hypertension
* snails are intermediate host cercariae penetrate skin of humans in contact with contaminated fresh water (eg. swimming or bathing)
*Schistosoma*
467
Trematodes (Flukes):
* egg with lateral spine
* liver and spleen enlargement, fibrosis, inflammation, and portal hypertension
*Schistosoma mansoni*
468
Trematodes (Flukes):
* chronic infection
* egg with terminal spine
* can lead to squamous cell carcinoma of the bladder (painless hematuria) and pulmonary hypertension
*Schistosoma haematobium*
469
*Schistosoma* is treated with \_\_\_\_\_.
Praziquantel
470
Cestodes (Tapeworms):
* biliary tract inflammation → pigmented gallstones
* associated with cholangiocarcinoma
* undercooked fish
*Clonorchis sinensis*
471
*Clonorchis sinensis* is treated with \_\_\_\_\_.
Praziquantel
472
Ectoparasites
* *Sarcoptes scabiei*
* *Pediculus humanus*
* *Phthirus pubis*
473
Ectoparasites:
* mites burrow into stratum corneum—pruritus (worse at night) and serpiginous burrows (lines) in webspace of hands and feet
* common in children, crowded populations (jails, nursing homes)
* transmission through skin-to-skin contact (most common) or via fomites
*Sarcoptes scabiei*
474
*Sarcoptes scabiei* is treated with \_\_\_\_\_.
* Permethrin cream
* washing/drying all clothing/bedding
* treat close contacts
475
Ectoparasites:
* blood-sucking lice that cause intense pruritus with associated excoriations, commonly on scalp and neck (head lice) or waistband and axilla (body lice)
* can transmit *Rickettsia prowazekii* (epidemic typhus), *Borrelia recurrentis* (relapsing fever), *Bartonella quintana* (trench fever).
* *Pediculus humanus*
* *Phthirus pubis*
476
*Pediculus humanus* and *Phthirus pubis* are treated with \_\_\_\_\_.
* Pyrethroids
* Malathion
* Ivermectin lotion
* nit combing
\*children with head lice can be treated at home without interrupting school attendance
477
Parasites:
* biliary tract disease
* cholangiocarcinoma
*Clonorchis sinensis*
478
Parasites:
Neurocysticercosis—brain cysts, seizures
*Taenia solium*
479
Parasites:
* hematuria
* squamous cell bladder cancer
*Schistosoma haematobium*
480
Parasites:
liver (hydatid) cysts
*Echinococcus granulosus*
481
Parasites:
microcytic anemia
* *Ancylostoma*
* *Necator*
482
Parasites:
* myalgias
* periorbital edema
*Trichinella spiralis*
483
Parasites:
perianal pruritus
*Enterobius*
484
Parasites:
portal hypertension
* *Schistosoma mansoni*
* *Schistosoma japonicum*
485
Parasites:
Vitamin B12 Deficiency
*Diphyllobothrium latum*
486
Viral Structure
487
Viral Genetics:
exchange of genes between 2 chromosomes by crossing over within regions of significant base sequence homology
Recombination
488
Viral Genetics:
* when viruses with segmented genomes (eg. influenza virus) exchange genetic material
* the 2009 novel H1N1 influenza A pandemic emerged via complex viral reassortment of genes from human, swine, and avian viruses
* has potential to cause antigenic shift.
Reassortment
489
Viral Genetics:
* when 1 of 2 viruses that infect the cell has a mutation that results in a nonfunctional protein, the nonmutated virus “complements” the mutated one by making a functional protein that serves both viruses
* hepatitis D virus requires the presence of replicating hepatitis B virus to supply HBsAg, the envelope protein for HDV
Complementation
490
Viral Genetics:
* occurs with simultaneous infection of a cell with 2 viruses
* genome of virus A can be partially or completely coated (forming pseudovirion) with the surface proteins of virus B
* type B protein coat determines the tropism (infectivity) of the hybrid virus
* the progeny from this infection have a type A coat that is encoded by its type A genetic material
Phenotypic Mixing
491
All DNA viruses have dsDNA genomes except \_\_\_\_\_.
Parvoviridae (ssDNA)
All are dsDNA (like our cells), except “**part-of-a-virus**” (**parvovirus**) is ssDNA.
*Parvus* = small
492
All DNA viruses are linear except \_\_\_\_\_.
Circular
* Papillomaviruses—supercoiled
* Polyomaviruses—supercoiled
* Hepadnaviruses—incomplete
493
All RNA viruses have ssRNA genomes except \_\_\_\_\_.
Reoviridae (dsRNA)
All are ssRNA, except “**re**peat**o**-virus” (**reovirus**) is dsRNA.
494
⊕ Stranded RNA Viruses
* Retrovirus
* Togavirus
* Flavivirus
* Coronavirus
* Hepevirus
* Calicivirus
* Picornavirus
I went to a **retro** **toga** party, where I drank **flav**ored **Corona** and ate **hippie** **Cali**fornia **pic**kles.
495
Naked Viral Genome Infectivity:
Purified nucleic acids of most dsDNA (except poxviruses and HBV) and ⊕ strand ssRNA (≈ mRNA) viruses are \_\_\_\_\_.
infectious
496
Naked Viral Genome Infectivity:
Naked nucleic acids of ⊝ strand ssRNA and dsRNA viruses are \_\_\_\_\_.
not infectious
497
Naked Viral Genome Infectivity:
Naked nucleic acids of ⊝ strand ssRNA and dsRNA viruses are not infectious. They require _____ contained in the complete virion.
polymerases
498
Generally, enveloped viruses acquire their envelopes from the _____ when they exit from cell.
plasma membrane
499
Generally, enveloped viruses acquire their envelopes from plasma membrane when they exit from cell. Exceptions include herpesviruses, which acquire envelopes from the \_\_\_\_\_.
nuclear membrane
500
Naked (Nonenveloped) Viruses
* **P**apillomavirus
* **A**denovirus
* **P**arvovirus
* **P**olyomavirus
* **C**alicivirus
* **P**icornavirus
* **R**eovirus
* **Hepe**virus
DNA = **PAPP**; RNA = **CPR** and **hepe**virus.
Give **PAPP** smears and **CPR** to a **naked** **hippie**.
501
DNA Viruses
**HHAPPPP**y Viruses:
* **H**epadna
* **H**erpes
* **A**deno
* **P**ox
* **P**arvo
* **P**apilloma
* **P**olyoma
502
DNA viruses are icosahedral except \_\_\_\_\_.
Pox (complex)
503
DNA viruses replicate in the nucleus except \_\_\_\_\_.
Pox
* carries own DNA-dependent RNA polymerase
**Pox** is out of the **box** (**nucleus**).
504
DNA Viruses:
* ⊕ envelope
* DS
* linear
Herpesviruses
505
DNA Viruses:
* ⊕ envelope
* DS
* linear
* largest DNA virus
* Molluscum Contagiosum—flesh-colored papule with central umbilication
Poxvirus
506
\_\_\_\_\_ was eradicated worldwide by use of the live-attenuated vaccine.
Smallpox
507
\_\_\_\_\_ presents with “milkmaid blisters”.
Cowpox
508
DNA Viruses:
* ⊕ envelope
* partially DS
* circular
* HBV
* acute or chronic hepatitis
* not a retrovirus but has reverse transcriptase
Hepadnavirus
509
DNA Viruses:
* ⊝ envelope
* DS
* linear
* febrile pharyngitis—sore throat
* acute hemorrhagic cystitis
* pneumonia
* conjunctivitis—“pink eye”
* gastroenteritis
Adenovirus
510
DNA Viruses:
* ⊝ envelope
* DS
* circular
* HPV
* warts—serotypes 1, 2, 6, 11
* CIN, cervical cancer—most commonly 16, 18
Papillomavirus
511
DNA Viruses:
* ⊝ envelope
* DS
* circular
* JC virus—progressive multifocal leukoencephalopathy (PML) in HIV
* BK virus—transplant patients, commonly targets kidney
Polyomavirus
**JC**: **J**unky **C**erebrum
**BK**: **B**ad **K**idney
512
DNA Viruses:
* ⊝ envelope
* SS
* linear
* smallest DNA virus
* B19 virus
* aplastic crises in sickle cell disease
* “slapped cheek” rash in children (erythema infectiosum, or fifth disease)
* RBC destruction in fetus leads to hydrops fetalis and death
* in adults it leads to pure RBC aplasia and rheumatoid arthritis-like symptoms
Parvovirus
513
Herpesviruses:
* transmitted through respiratory secretions and saliva
* gingivostomatitis
* keratoconjunctivitis
* herpes labialis
* herpetic whitlow on finger
* temporal lobe encephalitis
* esophagitis
* erythema multiforme
* most commonly latent in trigeminal ganglia
* most common cause of sporadic encephalitis; can present as altered mental status, seizures, and/or aphasia
Herpes Simplex Virus-1
514
Herpesviruses:
* transmitted through sexual contact, perinatal
* herpes genitalis
* neonatal herpes
* most commonly latent in sacral ganglia
* viral meningitis is more common
Herpes Simplex Virus-2
515
Herpesviruses:
* transmitted through respiratory secretions
* encephalitis
* pneumonia
* latent in dorsal root or trigeminal ganglia
* CN V1 branch involvement can cause Herpes Zoster Ophthalmicus
Varicella-Zoster Virus (HHV-3)
516
Herpesviruses:
* transmitted through respiratory secretions and saliva
* “kissing disease”(common in teens, young adults)
* Mononucleosis
* fever, hepatosplenomegaly, pharyngitis, and lymphadenopathy (especially posterior cervical nodes)
* avoid contact sports until resolution due to risk of splenic rupture
* associated with lymphomas (eg. endemic Burkitt lymphoma), nasopharyngeal carcinoma (especially Asian adults), and lymphoproliferative disease in transplant patients.
* infects B cells through CD21
* atypical lymphocytes on peripheral blood smear G—not infected B cells but reactive cytotoxic T cells
* ⊕ Monospot Test—heterophile antibodies detected by agglutination of sheep or horse RBCs
* use of amoxicillin in mononucleosis can cause characteristic maculopapular rash
Epstein-Barr Virus (HHV-4)
517
Herpesviruses:
* transmitted through congenital transfusion,
* sexual contact, saliva, urine, and transplant
* Mononucleosis (⊝ Monospot) in immunocompetent patients
* infection in immunocompromised, especially pneumonia in transplant patients
* esophagitis
* AIDS retinitis (“sightomegalovirus”)
* hemorrhage
* cotton-wool exudates
* vision loss
* infected cells have characteristic “owl eye” intranuclear inclusions
* latent in mononuclear cells
Cytomegalovirus (HHV-5)
AIDS retinitis = “**sightomegalovirus**”
518
Herpesviruses:
* transmitted through saliva
* Roseola Infantum (Exanthem Subitum)
* high fevers for several days that can cause seizures
* followed by diffuse macular rash
* Roseola
* fever first
* rosy (rash) later
Human Herpesviruses 6 and 7
HHV-7—less common cause of Roseola
519
Herpesviruses:
* transmitted through sexual contact
* Kaposi sarcoma (neoplasm of endothelial cells)
* seen in HIV/AIDS and transplant patients
* dark/violaceous plaques or nodules representing vascular proliferations
* can also affect GI tract and lungs
Human Herpesvirus 8
520
HSV Identification:
* skin
* genitalia
Viral Culture
521
HSV Identification:
Herpes Encephalitis
CSF PCR
522
HSV Identification:
skin lesions
PCR
523
HSV Identification:
a smear of an opened skin vesicle is used to detect multinucleated giant cells commonly seen in HSV-1, HSV-2, and VZV infection
Tzanck Test
**Tzanck** heavens I do not have **herpes**.
524
HSV Identification:
seen with HSV-1, HSV-2, VZV
Intranuclear Eosinophilic Cowdry Inclusions
525
Receptors:
CMV
Integrins (Heparan Sulfate)
526
Receptors:
EBV
CD21
527
Receptors:
HIV
* CD4
* CXCR4
* CCR5
528
Receptors:
Parvovirus B19
P antigen on RBCs
529
Receptors:
Rabies
Nicotinic AChR
530
Receptors:
Rhinovirus
ICAM-1
531
All RNA viruses replicate in the cytoplasm except \_\_\_\_\_.
* Retrovirus
* Influenza Virus
**Retro flu** is outta **cyt** (sight).
532
\_\_\_\_\_ are viruses that are arthropod borne (mosquitoes, ticks).
Arbovirus
533
Arboviruses
* Coltivirus
* Yellow Fever
* Dengue
* St. Louis Encephalitis
* West Nile Virus
* Zika Virus
* Western and Eastern Equine Encephalitis
* Chikungunya Virus
* California Encephalitis
* Sandfly Fever
* Rift Valley Fever
* Crimean-Congo Hemorrhagic Fever
534
RNA Viruses:
* ⊝ envelope
* DS
* linear
* 10–12 segments of RNA
* icosahedral (double) capsid
* Coltivirus—Colorado tick fever
* Rotavirus—cause of fatal diarrhea in children
Reoviruses
535
RNA Viruses:
* ⊝ envelope
* SS
* ⊕ linear
* icosahedral capsid
* Poliovirus—polio-Salk/Sabin vaccines—IPV/OPV
* Echovirus—aseptic meningitis
* Rhinovirus—“common cold”
* Coxsackievirus—aseptic meningitis; herpangina (mouth blisters, fever); hand, foot, and mouth disease; myocarditis; pericarditis
* HAV—acute viral hepatitis
Picornaviruses
**PERCH**
* **P**oliovirus
* **E**chovirus
* **R**hinovirus
* **C**oxsackievirus
* **H**AV
536
RNA Viruses:
* ⊝ envelope
* SS
* ⊕ linear
* icosahedral capsid
* HEV
Hepevirus
537
RNA Viruses:
* ⊝ envelope
* SS
* ⊕ linear
* icosahedral capsid
* Norovirus—viral gastroenteritis
Caliciviruses
538
RNA Viruses:
* ⊕ envelope
* SS
* ⊕ linear
* icosahedral capsid
* HCV
* Yellow Fever
* Dengue
* St. Louis Encephalitis
* West Nile Virus—meningoencephalitis
* Zika Virus
Flaviviruses
539
RNA Viruses:
* ⊕ envelope
* SS
* ⊕ linear
* icosahedral capsid
* Rubella
* Western and Eastern Equine Encephalitis
* Chikungunya Virus
Togaviruses
540
RNA Viruses:
* ⊕ envelope
* SS
* ⊕ linear
* 2 copies of RNA
* icosahedral capsid (HTLV)
* complex and conical capsid (HIV)
* have reverse transcriptase
* HTLV—T-Cell Leukemia
* HIV—AIDS
Retroviruses
541
RNA Viruses:
* ⊕ envelope
* SS
* ⊕ linear
* helical capsid
* “common cold”
* SARS
* MERS
Coronaviruses
542
RNA Viruses:
* ⊕ envelope
* SS
* ⊝ linear
* 8 segments of RNA
* helical capsid
* Influenza Virus
Orthomyxoviruses
543
RNA Viruses:
* ⊕ envelope
* SS
* ⊝ linear
* nonsegmented RNA
* helical capsid
* Parainfluenza—croup
* RSV—bronchiolitis in babies
* Measles
* Mumps
Paramyxoviruses
**P**a**R**a**M**yxovirus:
* **P**arainfluenza
* **R**SV
* **M**easles
* **M**umps
544
RNA Viruses:
* ⊕ envelope
* SS
* ⊝ linear
* helical capsid
* Rabies
Rhabdoviruses
545
RNA Viruses:
* ⊕ envelope
* SS
* ⊝ linear
* helical capsid
* Ebola/Marburg Hemorrhagic Fever—often fatal
Filoviruses
546
RNA Viruses:
* ⊕ envelope
* SS
* ⊕ and ⊝ circular
* 2 segments of RNA
* helical capsid
* LCMV—Lymphocytic Choriomeningitis Virus
* Lassa Fever Encephalitis—spread by rodents
Arenaviruses
547
RNA Viruses:
* ⊕ envelope
* SS
* ⊝ circular
* 3 segments of RNA
* helical capsid
* California Encephalitis
* Sandfly/Rift Valley Fevers
* Crimean-Congo Hemorrhagic Fever
* Hantavirus—hemorrhagic fever, pneumonia
Bunyaviruses
548
RNA Viruses:
* ⊕ envelope
* SS
* ⊝ circular
* uncertain capsid shape
* HDV is a “defective” virus that requires the
* presence of HBV to replicate
Delta Virus
549
\_\_\_\_\_ must transcribe ⊝ RNA strand to ⊕. Virion brings its own RNA-dependent RNA polymerase.
Negative-Stranded Viruses
550
Negative-Stranded Viruses
**A**lways **B**ring **P**olymerase **O**r **F**ail **R**eplication.
* **A**renaviruses
* **B**unyaviruses
* **P**aramyxoviruses
* **O**rthomyxoviruses
* **F**iloviruses
* **R**habdoviruses.
551
Segmented Viruses are all \_\_\_\_\_.
RNA Viruses
552
Segmented Viruses
**BOAR**
* **B**unyaviruses
* **O**rthomyxoviruses
* **A**renaviruses
* **R**eoviruses
553
\_\_\_\_\_ RNA is translated into 1 large polypeptide that is cleaved by proteases into functional viral proteins.
Picornavirus
Pico**RNA**virus = small **RNA** virus
554
Picornaviruses can cause aseptic (viral) meningitis except \_\_\_\_\_.
* Rhinovirus
* HAV
555
Picornaviruses are all enteroviruses except \_\_\_\_\_.
* Rhinovirus
* HAV
556
Picornaviruses
**PERCH** on a “**peak**” (**pic**o).
* **P**oliovirus
* **E**chovirus
* **R**hinovirus
* **C**oxsackievirus
* **H**AV
557
Viruses:
* Picornavirus
* nonenveloped RNA virus
* cause of common cold
* \> 100 serologic types
* acid labile—destroyed by stomach acid
* does not infect the GI tract (unlike the other picornaviruses)
Rhinovirus
**Rhino** has a runny **nose**.
558
Viruses:
* Flavivirus (also an arbovirus)
* transmitted by *Aedes* mosquitoes
* monkey or human reservoir
* causes high fever, black vomitus, and jaundice
* Councilman Bodies (eosinophilic apoptotic globules) on liver biopsy
Yellow Fever Virus
*Flavi* = yellow, jaundice
559
Viruses:
* Reovirus
* segmented dsRNA virus
* most important global cause of infantile gastroenteritis
* major cause of acute diarrhea in the US during winter, especially in day care centers, kindergartens
* villous destruction with atrophy leads to ↓ absorption of Na+ and loss of K+
* CDC recommends routine vaccination of all infants except those with a history of intussusception or SCID
Rotavirus
**ROTA**virus = **R**ight **O**ut **T**he **A**nus
560
Viruses:
* Orthomyxoviruses
* enveloped, ⊝ ssRNA viruses with 8-segment genome
* contain hemagglutinin (binds sialic acid and promotes viral entry) and neuraminidase (promotes progeny virion release) antigens
* patients at risk for fatal bacterial superinfection, most commonly *S. aureus*, *S. pneumoniae*, and *H. influenzae*
Influenza Viruses
561
Reformulated Influenza vaccine (“the flu shot”) contains viral strains most likely to appear during the flu season, due to the virus’ \_\_\_\_\_.
rapid genetic change
562
\_\_\_\_\_ Influenza vaccine is most frequently used.
Killed
563
\_\_\_\_\_ Influenza vaccine contains temperature-sensitive mutant that replicates in the nose but not in the lung; administered intranasally.
Live Attenuated
564
Influenza Viruses:
* causes pandemics
* reassortment of viral genome segments, such as when segments of human flu A virus reassort with swine flu A virus
Genetic/Antigenic Shift
**S**udden **s**hift is more deadly than gra**d**ual **d**rift.
565
Influenza Viruses:
* causes epidemics
* minor changes based on random mutation in hemagglutinin or neuraminidase genes
Genetic/Antigenic Drift
**S**udden **s**hift is more deadly than gra**d**ual **d**rift.
566
Viruses:
* Togavirus
* causes German (3-day) Measles
* causes fever, postauricular and other lymphadenopathy, arthralgias, and fine, maculopapular rash that starts on face and spreads centrifugally to involve trunk and extremities
* causes mild disease in children but serious congenital disease (a ToRCHeS infection)
* congenital infection presents with “blueberry muffin” appearance due to dermal extramedullary hematopoiesis
Rubella Virus
567
Viruses:
* cause disease in children
* include those that cause parainfluenza (croup), mumps, measles, RSV, and human metapneumovirus, which causes respiratory tract infection (bronchiolitis, pneumonia) in infants
* all contain surface F (fusion) protein, which causes respiratory epithelial cells to fuse and form multinucleated cells
Paramyxoviruses
568
\_\_\_\_\_, monoclonal antibody against F protein, prevents pneumonia caused by RSV infection in premature infants.
Palivizumab
**P**alivizumab for **P**aramyxovirus (RSV) **P**rophylaxis in **P**reemies.
569
Viruses:
* Paramyxoviruses
* causes Croup (Acute Laryngotracheobronchitis)
* virus membrane contains hemagglutinin (binds sialic acid and promotes viral entry) and neuraminidase (promotes progeny virion release) antigens
* results in a “seal-like” barking cough and inspiratory stridor
* narrowing of upper trachea and subglottis leads to characteristic steeple sign on x-ray
* severe Croup can result in pulsus paradoxus 2° to upper airway obstruction
Parainfluenza Viruses
570
Viruses:
* Paramyxovirus
* usual presentation involves prodromal fever with cough, coryza, and conjunctivitis, then eventually Koplik spots (bright red spots with blue-white center on buccal mucosa), followed 1–2 days later by a maculopapular rash that starts at the head/neck and spreads downward
* lymphadenitis with Warthin-Finkeldey giant cells (fused lymphocytes) in a background of paracortical hyperplasia
Measles (Rubeola) Virus
**3 C**’s of Measles:
* **C**ough
* **C**oryza
* **C**onjunctivitis
571
Sequelae of Measles
* SSPE
* Subacute Sclerosing Panencephalitis
* occurring years later
* Encephalitis
* 1:2000
* Giant Cell Pneumonia
* rare except in immunosuppressed
572
\_\_\_\_\_ supplementation can reduce morbidity and mortality from measles, particularly in malnourished children.
Vitamin A
573
Viruses:
* Paramyxovirus
* uncommon due to effectiveness of MMR vaccine
* causes parotitis, orchitis (inflammation of testes), aseptic meningitis, and pancreatitis.
* can cause sterility (especially after puberty).
Mumps Virus
**Mumps** makes your parotid glands and testes as
big as **POM**-**P**oms.
* **P**arotitis
* **O**rchitis
* aseptic **M**eningitis
* **P**ancreatitis
574
Viruses:
* bullet-shaped virus
* Negri bodies (cytoplasmic inclusions) commonly found in Purkinje cells of cerebellum and in hippocampal neurons
* has long incubation period (weeks to months) before symptom onset
* Postexposure prophylaxis is wound cleaning plus immunization with killed vaccine and rabies immunoglobulin
* example of passive-active immunity
Rabies Virus
575
Viruses:
* travels to the CNS by migrating in a retrograde fashion (via dynein motors) up nerve axons after binding to ACh receptors
* _Progression of Disease_:
* fever, malaise → agitation, photophobia, hydrophobia, hypersalivation → paralysis, coma → death
* infection more commonly from bat, raccoon, and skunk bites than from dog bites in the US
* aerosol transmission (eg. bat caves) also possible
Rabies Virus
576
Viruses:
* Filovirus
* targets endothelial cells, phagocytes, and hepatocytes
* following an incubation period of up to 21 days, presents with abrupt onset of flu-like symptoms, diarrhea/vomiting, high fever, and myalgia.
* can progress to DIC, diffuse hemorrhage, shock
* diagnosed with RT-PCR within 48 hr of symptom onset
* high mortality rate
Ebola Virus
577
Viruses:
* Filovirus
* targets endothelial cells, phagocytes, and hepatocytes
* transmission requires direct contact with bodily fluids, fomites (including dead bodies), and infected bats or primates (apes/monkeys)
* high incidence of nosocomial infection
* supportive care, no definitive treatment
* strict isolation of infected individuals and barrier practices for health care workers are key to preventing transmission
Ebola Virus
578
Viruses:
* Flavivirus
* most commonly transmitted by *Aedes* mosquito bites
* causes conjunctivitis, low-grade pyrexia, and itchy rash in 20% of cases
* can lead to congenital microcephaly or miscarriage if transmitted in utero
* diagnose with RT-PCR or serology
* sexual and vertical transmission possible
* outbreaks more common in tropical and subtropical climates
* supportive care, no definitive treatment
Zika Virus
579
Viruses:
* episodes of fever and jaundice
* ↑ ALT and AST
Hepatitis Viruses
580
Naked viruses (HAV and HEV) lack an envelope and are not destroyed by the \_\_\_\_\_.
gut
H**A**V, H**E**V = The **vowels** hit your **bowels**.
581
HBV DNA Polymerase
* HBV DNA polymerase has DNA- and RNA-dependent activities.
* Upon entry into nucleus, the polymerase completes the partial dsDNA.
* Host RNA polymerase transcribes mRNA from viral DNA to make viral proteins.
* The DNA polymerase then reverse transcribes viral RNA to DNA, which is the genome of the progeny virus.
582
HCV lacks _____ activity → no proofreading ability → variation in antigenic structures of HCV envelope proteins. Host antibody production lags behind production of new mutant strains of HCV.
3′-5′ Exonuclease
583
Hepatitis Viruses:
* RNA Picornavirus
* fecal-oral route (shellfish, travelers, day care)
* Incubation Period—short (weeks)
* asymptomatic (usually), acute
* good prognosis
* no risk for HCC
* Liver Biopsy:
* hepatocyte swelling
* monocyte infiltration
* Councilman bodies
* no carrier state
HAV
**A**symptomatic, **A**cute, **A**lone
584
Hepatitis Viruses:
* DNA Hepadnavirus
* parenteral, sexual, and perinatal transmission
* Incubation Period—long (months)
* initially like serum sickness (fever, arthralgias, rash)
* may progress to carcinoma
* risk for HCC
* adults → mostly full resolution
* neonates → worse prognosis
* Liver Biopsy:
* granular eosinophilic “ground glass” appearance
* cytotoxic T cells mediate damage
* carrier state common
HBV
**B**lood, **B**abymaking, **B**irthing
585
Hepatitis Viruses:
* RNA Flavivirus
* transmitted through blood (IVDU, post-transfusion)
* Incubation Period—long
* may progress to cirrhosis or carcinoma
* risk for HCC
* majority develop stable, chronic hepatitis C
* Liver Biopsy:
* lymphoid aggregates with focal areas of macrovesicular steatosis
* carrier state very common
HCV
**C**irrhosis, **C**arcinoma, **C**hronic, **C**arrier
586
Hepatitis Viruses:
* RNA Deltavirus
* parenteral, sexual, and perinatal transmission
* Superinfection (HDV after HBV) = short
* Coinfection (HDV with HBV) = long
* initially like serum sickness (fever, arthralgias, rash)
* may progress to carcinoma
* risk for HCC
* Superinfection → worse prognosis
* Liver Biopsy:
* granular eosinophilic “ground glass” appearance
* cytotoxic T cells mediate damage
* defective virus—depends on HBV HBsAg coat for entry into hepatocytes
HDV
**D**eltavirus, **D**efective
587
Hepatitis Viruses:
* RNA Hepevirus
* fecal-oral route, especially waterborne
* Incubation Period—short
* fulminant hepatitis in expectant (pregnant) women
* high mortality in pregnant women
* no risk for HCC
* Liver Biopsy:
* patchy necrosis
* enteric
* epidemic
* no carrier state
HEV
**E**xpectant, **E**nteric, **E**pidemic
588
Extrahepatic Hepatitis Viruses:
* Aplastic Anemia
* Membranous GN \> Membranoproliferative GN
* Polyarteritis Nodosa
Hepatitis B
589
Extrahepatic Hepatitis Viruses:
* Essential Mixed Cryoglobulinemia
* ↑ risk B-cell NHL
* ITP
* Autoimmune Hemolytic Anemia
* Membranoproliferative GN \> Membranous GN
* Leukocytoclastic Vasculitis
* Sporadic Porphyria Cutanea Tarda
* Lichen Planus
* ↑ risk of Diabetes Mellitus
* Autoimmune Hypothyroidism
Hepatitis C
590
Hepatitis Serologic Markers
591
Hepatitis Serologic Markers:
best test to detect acute hepatitis A
Anti-HAV (IgM)
592
Hepatitis Serologic Markers:
* indicates prior HAV infection and/or prior vaccination
* protects against reinfection
Anti-HAV (IgG)
593
Hepatitis Serologic Markers:
* antigen found on surface of HBV
* indicates hepatitis B infection
HBsAg
594
Hepatitis Serologic Markers:
indicates immunity to hepatitis B due to vaccination or recovery from infection
Anti-HBs
595
Hepatitis Serologic Markers:
antigen associated with core of HBV
HBcAg
596
Hepatitis Serologic Markers:
* IgM = acute/recent infection
* IgG = prior exposure or chronic infection
* IgM may be the sole ⊕ marker of infection during window period
Anti-HBc
597
Hepatitis Serologic Markers:
* secreted by infected hepatocyte into circulation
* not part of mature HBV virion
* indicates active viral replication and therefore high transmissibility and poorer prognosis
HBeAg
598
Hepatitis Serologic Markers:
indicates low transmissibility
Anti-HBe
599
HIV
600
HIV has _____ genome (2 molecules of RNA).
Diploid
601
HIV Structural Genes and Proteins
* *env* (gp120 and gp41):
* formed from cleavage of gp160 to form envelope glycoproteins
* gp120—attachment to host CD4+ T cell
* gp41—fusion and entry
* *gag* (p24 and p17)
* capsid and matrix proteins, respectively
* *pol*
* **reverse transcriptase, aspartate protease, integrase
602
HIV _____ synthesizes dsDNA from genomic RNA; dsDNA integrates into host genome.
Reverse Transcriptase
603
HIV binds _____ as well as a coreceptor, either _____ on macrophages (early infection) or _____ on T cells (late infection).
CD4
Coreceptors
* CCR5 on macrophages (early infection)
* CXCR4 on T cells (late infection)
604
HIV:
homozygous CCR5 mutation
Immunity
605
HIV:
heterozygous CCR5 mutation
slower course
606
HIV Diagnosis:
* presumptive diagnosis
* detect viral p24 Ag capsid protein and IgG Abs to HIV-1/2
* very high sensitivity/specificity
HIV-1/2 Ag/Ab Immunoassays
607
HIV Diagnosis:
* confirmation of ⊕ HIV-1/2 Ag/Ab immunoassay tests
* determine whether patient has HIV-1 or HIV-2
HIV-1/2 Ab-Differentiation Immunoassays
608
HIV Diagnosis:
* done if inconclusive differentiation assay
* if ⊝, patient had false positive initial Ag/Ab immunoassay
HIV‑1 Nucleic Acid Amplification Test (NAAT)
609
HIV Diagnosis:
* determine the amount of viral RNA in the plasma
* high levels are associated with poor prognosis
* used to monitor effect of drug therapy
Viral Load Tests
610
HIV Diagnosis:
determine appropriate therapy
HIV Genotyping
611
HIV Diagnosis:
AIDS CD4 levels
≤ 200 CD4+ cells/mm3
\*HIV ⊕ with AIDS-defining condition (eg. *Pneumocystis* pneumonia) or CD4+ percentage \< 14%
| (normal: 500–1500 cells/mm3)
612
HIV-1/2 Ag/Ab testing is not recommended in babies with suspected HIV due to maternally transferred antibodies. _____ is used instead.
HIV Viral Load
613
Time Course of Untreated HIV Infection
* Dashed lines on CD4+ count axis indicate moderate immunocompromise (\< 400 CD4+ cells/mm3) and when AIDS-defining illnesses emerge (\< 200 CD4+ cells/mm3).
* Most patients who do not receive treatment eventually die of complications of HIV infection.
* During clinical latency phase, the virus replicates in lymph nodes.
**F**our Stages of Untreated HIV:
1. **F**lu-like (acute)
2. **F**eeling fine (latent)
3. **F**alling count
4. **F**inal crisis
614
Common Diseases of HIV⊕ Adults:
CD4+ cell count \< 500/mm3
* *Candida albicans*
* EBV
* HHV-8
* HPV
615
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 500/mm3
* *Candida albicans*
* scrapable white plaque
* pseudohyphae on microscopy
Oral Thrush
616
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 500/mm3
* EBV
* unscrapable white plaque on lateral tongue
Oral Hairy Leukoplakia
617
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 500/mm3
* HHV-8
* biopsy with lymphocytic inflammation
Kaposi Sarcoma
618
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 500/mm3
* HPV
Squamous Cell Carcinoma
* commonly of anus—men who have sex with men
* cervix—women
619
Common Diseases of HIV⊕ Adults:
CD4+ cell count \< 200/mm3
* *Histoplasma* *capsulatum*
* HIV
* JC Virus (reactivation)
* *Pneumocystis jirovecii*
620
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 200/mm3
* fever, weight loss, fatigue, cough, dyspnea, nausea, vomiting, diarrhea
* oval yeast cells within macrophages
*Histoplasma capsulatum*
621
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 200/mm3
* HIV
Dementia
622
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 200/mm3
* JC Virus (reactivation)
* nonenhancing areas of demyelination on MRI
Progressive Multifocal Leukoencephalopathy
623
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 200/mm3
* pneumonia
* “ground-glass” opacities on CXR
*Pneumocystis jirovecii*
624
Common Diseases of HIV⊕ Adults:
CD4+ cell count \< 100/mm3
* *Aspergillus fumigatus*
* *Bartonella henselae*
* *Candida albicans*
* CMV
* *Cryptococcus neoformans*
* *Cryptosporidium* spp.
* EBV
* *Mycobacterium avium–intracellulare* (*Mycobacterium avium* Complex)
* *Toxoplasma gondii*
625
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 100/mm3
* hemoptysis, pleuritic pain
* cavitation or infiltrates on chest imaging
*Aspergillus fumigatus*
626
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 100/mm3
* *Bartonella henselae*
* biopsy with neutrophilic inflammation
Bacillary Angiomatosis
627
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 100/mm3
* *Candida albicans*
* white plaques on endoscopy
* yeast and pseudohyphae on biopsy
Esophagitis
628
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 100/mm3
* retinitis, esophagitis, colitis, pneumonitis, encephalitis
* linear ulcers on endoscopy, cotton-wool spots on fundoscopy
* biopsy reveals cells with intranuclear (owl eye) inclusion bodies
CMV
629
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 100/mm3
* meningitis
* encapsulated yeast on India ink stain or capsular antigen ⊕
*Cryptococcus neoformans*
630
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 100/mm3
* chronic, watery diarrhea
* acid-fast oocysts in stool
*Cryptosporidium* spp.
631
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 100/mm3
* B-cell lymphoma (eg. non-Hodgkin lymphoma, CNS lymphoma)
* CNS lymphoma—ring enhancing, may be solitary (vs. *Toxoplasma*)
EBV
632
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 100/mm3
* nonspecific systemic symptoms (fever, night sweats, weight loss) or focal lymphadenitis
*Mycobacterium avium–intracellulare*
(*Mycobacterium avium* Complex)
633
Common Diseases of HIV⊕ Adults:
* CD4+ cell count \< 100/mm3
* brain abscesses
* multiple ring-enhancing lesions on MRI
*Toxoplasma gondii*
634
Prion diseases are caused by the conversion of a normal (predominantly α-helical) protein termed prion protein (PrPc) to a \_\_\_\_\_, which is transmissible via CNS-related tissue (iatrogenic CJD) or food contaminated by BSE-infected animal products (variant CJD).
β-pleated form (PrPsc)
635
Prion Diseases:
transmissible via CNS-related tissue
Iatrogenic CJD
636
Prion Diseases:
transmissible via food contaminated by BSE-infected animal products
Variant CJD
637
PrPsc resists _____ and facilitates the conversion of still more PrPc to PrPsc.
protease degradation
638
Prions are resistant to standard sterilizing procedures, including standard \_\_\_\_\_.
autoclaving
639
Accumulation of PrPsc results in \_\_\_\_\_.
* spongiform encephalopathy
* dementia
* ataxia
* death
640
Prion Diseases:
* rapidly progressive dementia
* typically sporadic (some familial forms)
Creutzfeldt-Jakob Disease
641
Prion Diseases:
also known as “mad cow disease”
Bovine Spongiform Encephalopathy
642
Prion Diseases:
acquired prion disease noted in tribal populations practicing human cannibalism
Kuru
643
Normal Flora:
skin
*S. epidermidis*
644
Normal Flora:
nose
* *S. epidermidis*
* *S. aureus*
645
Normal Flora:
oropharynx
Viridans Group Streptococci
646
Normal Flora:
dental plaque
*S. mutans*
647
Normal Flora:
colon
* *B. fragilis*
* *E. coli*
648
Normal Flora:
vagina
* *Lactobacillus*
* *E. coli*
* Group B Strep
649
\_\_\_\_\_ food poisoning starts quickly and ends quickly.
* *S. aureus*
* *B. cereus*
650
Bugs Causing Foodborne Illness:
reheated rice
*B. cereus*
“Food poisoning from reheated rice? **Be serious**!”
651
Bugs Causing Foodborne Illness:
* improperly canned foods (toxins)
* raw honey (spores)
*C. botulinum*
652
Bugs Causing Foodborne Illness:
reheated meat
*C. perfringens*
653
Bugs Causing Foodborne Illness:
undercooked meat
*E. coli* O157:H7
654
Bugs Causing Foodborne Illness:
* deli meats
* soft cheeses
*L. monocytogenes*
655
Bugs Causing Foodborne Illness:
* poultry
* meat
* eggs
*Salmonella*
656
Bugs Causing Foodborne Illness:
* meats
* mayonnaise
* custard
* preformed toxin
*S. aureus*
657
Bugs Causing Foodborne Illness:
contaminated seafood
* *V. parahaemolyticus*
* *V. vulnificusa*
658
\_\_\_\_\_ can cause wound infections from contact with contaminated water or shellfish.
*V. vulnificus*
659
Bugs Causing Bloody Diarrhea:
* comma- or S-shaped organisms
* growth at 42°C
*Campylobacter*
660
Bugs Causing Bloody Diarrhea:
* protozoan
* amebic dysentery
* liver abscess
*E. histolytica*
661
Bugs Causing Bloody Diarrhea:
* O157:H7
* can cause HUS
* makes Shiga-like toxin
Enterohemorrhagic *E. coli*
662
Bugs Causing Bloody Diarrhea:
invades colonic mucosa
Enteroinvasive *E. coli*
663
Bugs Causing Bloody Diarrhea:
* lactose ⊝
* flagellar motility
* has animal reservoir
* especially poultry and eggs
*Salmonella* (nontyphoidal)
664
Bugs Causing Bloody Diarrhea:
* lactose ⊝
* very low ID50
* produces Shiga toxin (human reservoir only)
* bacillary dysentery
*Shigella*
665
Bugs Causing Bloody Diarrhea:
* day care outbreaks
* pseudoappendicitis
*Y. enterocolitica*
666
Bugs Causing Watery Diarrhea:
* pseudomembranous colitis
* associated with antibiotics and PPIs
* occasionally bloody diarrhea
*C. difficile*
667
Bugs Causing Watery Diarrhea:
also causes gas gangrene
*C. perfringens*
668
Bugs Causing Watery Diarrhea:
* travelers’ diarrhea
* heat-labile (LT) toxin
* heat-stable (ST) toxin
Enterotoxigenic *E. coli*
669
Bugs Causing Watery Diarrhea:
protozoa
* *Giardia*
* *Cryptosporidium*
670
Bugs Causing Watery Diarrhea:
* comma-shaped organisms
* rice-water diarrhea
* often from infected seafood
*V. cholerae*
671
Bugs Causing Watery Diarrhea:
viruses
* Rotavirus
* Norovirus
* Enteric Adenovirus
672
Common Causes of Pneumonia:
Neonates (\< 4 wks.)
* Group B Streptococci
* *E. coli*
673
Common Causes of Pneumonia:
Children (4 wks.-18 yrs.)
**R**unts **M**ay **C**ough **C**hunky **S**putum
* Viruses (**R**SV)
* ***M**ycoplasma*
* ***C**. trachomatis* (infants–3 yr.)
* ***C**. pneumoniae* (school-aged children)
* ***S**. pneumoniae*
674
Common Causes of Pneumonia:
Adults (18-40 yrs.)
* *Mycoplasma*
* *C. pneumoniae*
* *S. pneumoniae*
* Viruses (eg. influenza)
675
Common Causes of Pneumonia:
Adults (40-65 yrs.)
* *S. pneumoniae*
* *H. influenzae*
* Anaerobes
* Viruses
* *Mycoplasma*
676
Common Causes of Pneumonia:
Elderly
* *S. pneumoniae*
* Influenza Virus
* Anaerobes
* *H. influenzae*
* Gram ⊝ Rods
677
Common Causes of Pneumonia:
Alcoholics
* *Klebsiella*
* Anaerobes—usually due to aspiration (eg. *Peptostreptococcus*, *Fusobacterium*, *Prevotella*, *Bacteroides*)
678
Common Causes of Pneumonia:
IV Drug Users
* *S. pneumoniae*
* *S. aureus*
679
Common Causes of Pneumonia:
Aspiration
Anaerobes
680
Common Causes of Pneumonia:
Atypical
* *Mycoplasma*
* *Chlamydophila*
* *Legionella*
* Viruses (RSV, CMV, Influenza, Adenovirus)
681
Common Causes of Pneumonia:
Cystic Fibrosis
* *Pseudomonas*
* *S. aureus*
* *S. pneumoniae*
* *Burkholderia cepacia*
682
Common Causes of Pneumonia:
Immunocompromised
* *S. aureus*
* Enteric Gram ⊝ Rods
* Fungi
* Viruses
* *P. jirovecii* (with HIV)
683
Common Causes of Pneumonia:
Nosocomial (hospital acquired)
* *S. aureus*
* *Pseudomonas*
* Enteric Gram ⊝ Rods
684
Common Causes of Pneumonia:
Postviral
* *S. pneumoniae*
* *S. aureus*
* *H. influenzae*
685
Common Causes of Meningitis:
Newborns (0-6 mos.)
* Group B Streptococci
* *E. coli*
* *Listeria*
686
Common Causes of Meningitis:
Children (6 mos.-6 yrs.)
* *S. pneumoniae*
* *N. meningitidis*
* *H. influenzae* type b
* Enteroviruses
687
Common Causes of Meningitis:
6-60 yrs.
* *S. pneumoniae*
* *N. meningitidis* (#1 in teens)
* Enteroviruses
* HSV
688
Common Causes of Meningitis:
60+ yrs.
* *S. pneumoniae*
* Gram ⊝ Rods
* *Listeria*
689
Meningitis is empirically treated with \_\_\_\_\_.
* Ceftriaxone
* Vancomycin
* Ampicillin—if *Listeria* is suspected
690
Viral Causes of Meningitis
* Enteroviruses (especially coxsackievirus)
* HSV-2 (HSV-1 = encephalitis)
* HIV
* West Nile Virus (also causes encephalitis)
* VZV
691
Common Causes of Meningitis:
HIV
*Cryptococcus* spp.
692
Cerebrospinal Fluid Findings in Meningitis:
* ↑ opening pressure
* ↑ PMNs
* ↑ protein
* ↓ glucose
Bacterial
693
Cerebrospinal Fluid Findings in Meningitis:
* ↑ opening pressure
* ↑ lymphocytes
* ↑ protein
* ↓ glucose
* Fungal
* TB
694
Cerebrospinal Fluid Findings in Meningitis:
* normal/↑ opening pressure
* ↑ lymphocytes
* normal/↑ protein
* normal glucose
Viral
695
Infections Causing Brain Abscess:
most common
* Viridans Streptococci
* *Staphylococcus aureus*
696
Infections Causing Brain Abscess:
dental infection or extraction
Oral Anaerobes
697
Infections Causing Brain Abscess:
multiple abscesses
Bacteremia
698
Infections Causing Brain Abscess:
single lesions
_Contiguous Sites_:
* otitis media and mastoiditis → temporal lobe and cerebellum
* sinusitis or dental infection → frontal lobe
699
Infections Causing Brain Abscess:
AIDS
*Toxoplasma* Reactivation
700
Osteomyelitis:
most common
*S. aureus*
701
Osteomyelitis:
sexually active
*Neisseria gonorrhoeae*
* rare
* septic arthritis more common
702
Osteomyelitis:
Sickle Cell Disease
* *Salmonella*
* *S. aureus*
703
Osteomyelitis:
prosthetic joint replacement
* *S. aureus*
* *S. epidermidis*
704
Osteomyelitis:
vertebral involvement
* *S. aureus*
* *Mycobacterium tuberculosis* (Pott disease)
705
Osteomyelitis:
cat and dog bites
*Pasteurella multocida*
706
Osteomyelitis:
IV drug abuse
* *S. aureus*
* *Pseudomonas*
* *Candida*
707
\_\_\_\_\_ are insensitive early but can be useful in chronic osteomyelitis.
Radiographs
708
\_\_\_\_\_ is best for detecting acute osteomyelitis and detailing anatomic involvement.
MRI
709
Cystitis presents with \_\_\_\_\_.
* dysuria
* frequency
* urgency
* suprapubic pain
* WBCs (but not WBC casts) in urine
710
Cystitis is primarily caused by \_\_\_\_\_.
ascension of microbes from urethra to bladder
711
Ascension of microbes from the urethra to the kidneys results in pyelonephritis, which presents with \_\_\_\_\_.
* fever
* chills
* flank pain
* costovertebral angle tenderness
* hematuria
* WBC casts
712
Urinary tract infections are ten times more common in women due to \_\_\_\_\_.
shorter urethras colonized by fecal flora
713
Predisposing Factors to UTI
* female
* males with congenital defects or vesicoureteral reflux
* obstruction
* kidney surgery
* catheterization
* GU malformation
* diabetes
* pregnancy
* elderly—enlarged prostate
714
Urinary Tract Infections:
* leading cause of UTI
* colonies show strong pink lactose-fermentation on MacConkey agar
*Escherichia coli*
715
Urinary Tract Infections:
2nd leading cause of UTI in sexually active women
*Staphylococcus saprophyticus*
716
Urinary Tract Infections:
* 3rd leading cause of UTI
* large mucoid capsule
* viscous colonies
*Klebsiella pneumoniae*
717
Urinary Tract Infections:
* some strains produce a red pigment
* often nosocomial and drug resistant
*Serratia marcescens*
718
Urinary Tract Infections:
often nosocomial and drug resistant
*Enterococcus*
719
Urinary Tract Infections:
* motility causes “swarming” on agar
* associated with struvite stones
*Proteus mirabilis*
720
Urinary Tract Infections:
* blue-green pigment
* fruity odor
* usually nosocomial and drug resistant
*Pseudomonas aeruginosa*
721
UTI Diagnostic Markers:
evidence of WBC activity
Leukocyte Esterase
722
UTI Diagnostic Markers:
reduction of urinary nitrates by bacterial species (eg. *E coli*)
Nitrite Test
723
UTI Diagnostic Markers:
urease-producing bugs (eg. *S. saprophyticus*, *Proteus*, *Klebsiella*)
Urease Test
724
Common Vaginal Infections:
* no inflammation
* thin, white discharge with fishy odor
* clue cells
* pH \> 4.5
Bacterial Vaginosis
725
Bacterial Vaginosis is treated with \_\_\_\_\_.
* Metronidazole
* Clindamycin
726
Common Vaginal Infections:
* inflammation (“strawberry cervix”)
* frothy, yellow-green, foul-smelling discharge
* motile trichomonads
* pH \> 4.5
*Trichomonas* Vaginitis
727
*Trichomonas* Vaginitis is treated with \_\_\_\_\_.
* Metronidazole
* treat sexual partner(s)
728
Common Vaginal Infections:
* inflammation
* thick, white, “cottage cheese” discharge
* pseudohyphae
* pH normal (4.0–4.5)
*Candida* Vulvovaginitis
729
*Candida* Vulvovaginitis is treated with \_\_\_\_\_.
Azoles
730
ToRCHeS Infections
* ***To**xoplasma gondii*
* **R**ubella
* **C**ytomegalovirus
* **H**IV
* **He**rpes Simplex Virus-2
* **S**yphilis
731
Transmission of ToRCHeS infections is _____ in most cases, or via _____ (especially HSV-2).
* transplacental
* delivery
\*Other important infectious agents include *Streptococcus agalactiae* (group B streptococci), *E. coli*, and *Listeria monocytogenes*—all causes of meningitis in neonates.
\*Parvovirus B19 causes hydrops fetalis.
732
Nonspecific Signs of ToRCHeS Infections
* hepatosplenomegaly
* jaundice
* thrombocytopenia
* growth retardation
733
ToRCHeS Infections:
* _Mode of Transmission_:
* cat feces
* ingestion of undercooked meat
* _Maternal Symptoms_:
* usually asymptomatic
* lymphadenopathy (rarely)
* _Neonatal Symptoms_:
* Classic Triad:
* chorioretinitis
* hydrocephalus
* intracranial calcifications
* +/− “blueberry muffin” rash
*Toxoplasma gondii*
734
ToRCHeS Infections:
* _Mode of Transmission_:
* respiratory droplets
* _Maternal Symptoms_:
* rash
* lymphadenopathy
* polyarthritis
* polyarthralgia
* _Neonatal Symptoms_:
* Classic Triad:
* cataracts
* deafness
* congenital heart disease (PDA)
* ± “blueberry muffin” rash
Rubella
“**I** (eye) **♥** **rub**y (rubella) **ear**rings.”
735
ToRCHeS Infections:
* _Mode of Transmission_:
* sexual contact
* organ transplants
* _Maternal Symptoms_:
* usually asymptomatic
* mononucleosis-like illness
* _Neonatal Symptoms_:
* hearing loss
* seizures
* petechial rash
* “blueberry muffin” rash
* chorioretinitis
* periventricular calcifications
Cytomegalovirus
736
ToRCHeS Infections:
* _Mode of Transmission_:
* sexual contact
* needlestick
* _Maternal Symptoms_:
* variable presentation depending on CD4+ cell count
* _Neonatal Symptoms_:
* recurrent infections
* chronic diarrhea
HIV
737
ToRCHeS Infections:
* _Mode of Transmission_:
* skin or mucous membrane contact
* _Maternal Symptoms_:
* usually asymptomatic
* herpetic (vesicular) lesions
* _Neonatal Symptoms_:
* meningoencephalitis
* herpetic (vesicular) lesions
Herpes Simplex Virus-2
738
ToRCHeS Infections:
* _Mode of Transmission_:
* sexual contact
* _Maternal Symptoms_:
* chancre (1°)
* disseminated rash (2°)
* _Neonatal Symptoms_:
* stillbirth
* hydrops fetalis
* facial abnormalities (eg. notched teeth, saddle nose, short maxilla)
* saber shins
* CN VIII deafness
Syphilis
739
Red Rashes of Childhood:
* Hand-Foot-Mouth Disease
* oval-shaped vesicles on palms and soles
* vesicles and ulcers in oral mucosa
Coxsackievirus type A
740
Red Rashes of Childhood:
* Roseola (Exanthem Subitum)
* symptomatic rose-colored macules appear on body after several days of high fever
* can present with febrile seizures
* usually affects infants
Human Herpesvirus 6
741
Red Rashes of Childhood:
* Rubeola
* confluent rash beginning at head and moving down
* preceded by cough, coryza, conjunctivitis, and blue-white (Koplik) spots on buccal mucosa
Measles Virus
742
Red Rashes of Childhood:
* Erythema Infectiosum (Fifth Disease)
* “slapped cheek” rash on face B (can cause hydrops fetalis in pregnant women)
Parvovirus B19
743
Red Rashes of Childhood:
* pink macules and papules begin at head and move down, remain discrete → fine desquamating truncal rash
* postauricular lymphadenopathy
Rubella Virus
744
Red Rashes of Childhood:
* Scarlet Fever
* flushed cheeks and circumoral pallor on the face
* erythematous, sandpaper-like rash from neck to trunk and extremities
* fever and sore throat
*Streptococcus pyogenes*
745
Red Rashes of Childhood:
* Chickenpox
* vesicular rash begins on trunk
* spreads to face and extremities with lesions of different stages
Varicella-Zoster Virus
746
Sexually Transmitted Infections:
* opportunistic infections
* Kaposi sarcoma
* lymphoma
* HIV
AIDS
747
Sexually Transmitted Infections:
* painful genital ulcer with exudate
* inguinal adenopathy
* *Haemophilus ducreyi*
Chancroid
It’s so painful, you “**do cry**”.
748
Sexually Transmitted Infections:
* urethritis
* cervicitis
* epididymitis
* conjunctivitis
* reactive arthritis
* PID
*Chlamydia trachomatis* (D–K)
749
Sexually Transmitted Infections:
* Condylomata Acuminata
* genital warts
* koilocytes
HPV-6 and -11
750
Sexually Transmitted Infections:
* Genital Herpes
* painful penile, vulvar, or cervical vesicles and ulcers
* can cause systemic symptoms such as fever, headache, and myalgia
HSV-2, less commonly HSV-1
751
Sexually Transmitted Infections:
* urethritis
* cervicitis
* PID,
* prostatitis
* epididymitis
* arthritis
* creamy purulent discharge
*Neisseria gonorrhoeae*
752
Sexually Transmitted Infections:
* painless, beefy red ulcer that bleeds readily on contact
* uncommon in US
* *Klebsiella (Calymmatobacterium) granulomatis*
* cytoplasmic Donovan bodies (bipolar staining) seen on microscopy
Granuloma Inguinale
| (Donovanosis)
753
Sexually Transmitted Infections:
* jaundice
* HBV
Hepatitis B
754
Sexually Transmitted Infections:
* infection of lymphatics
* painless genital ulcers
* painful lymphadenopathy (ie. buboes)
* *Chlamydia trachomatis* (L1–L3)
Lymphogranuloma Vvenereum
755
Sexually Transmitted Infections:
* painless chancre
* *Treponema pallidum*
Primary Syphilis
756
Sexually Transmitted Infections:
* fever
* lymphadenopathy
* skin rashes
* condylomata lata
* *Treponema pallidum*
Secondary Syphilis
757
Sexually Transmitted Infections:
* gummas
* tabes dorsalis
* general paresis
* aortitis
* Argyll Robertson pupil
* *Treponema pallidum*
Tertiary Syphilis
758
Sexually Transmitted Infections:
* vaginitis
* strawberry cervix
* motile in wet prep
*Trichomonas vaginalis*
759
\_\_\_\_\_ presents with cervical motion tenderness, adnexal tenderness, purulent cervical discharge.
Pelvic Inflammatory Disease
760
Pelvic Inflammatory Disease may include \_\_\_\_\_.
* salpingitis
* endometritis
* hydrosalpinx
* tubo-ovarian abscess
761
Pelvic Inflammatory Disease:
Pathogens
* *Chlamydia trachomatis*
* subacute
* often undiagnosed
* most common bacterial STI in the US
* *Neisseria gonorrhoeae*
* acute
762
\_\_\_\_\_ is a risk factor for ectopic pregnancy, infertility, chronic pelvic pain, and adhesions.
Salpingitis
763
Pelvic inflammatory disease can lead to _____ (perihepatitis)—infection and inflammation of the liver capsule and “violin string” adhesions of peritoneum to liver.
Fitz-Hugh-Curtis Syndrome
764
\_\_\_\_\_ are the most common causes nosocomial infections.
* *E. coli* (UTI)
* *S. aureus* (wound infection)
765
Nosocomial Infections:
* antibiotic use
* watery diarrhea
* leukocytosis
*Clostridium difficile*
766
Nosocomial Infections:
* aspiration (2° to altered mental status, old age)
* right lower lobe infiltrate or right upper/middle lobe (patient recumbent)
* purulent malodorous sputum
* Polymicrobial
* Gram ⊝ Bacteria
* Anaerobes
767
Nosocomial Infections:
* decubitus ulcers
* surgical wounds
* drains
* erythema, tenderness, induration, and drainage from surgical wound sites
* *S. aureus* (including MRSA)
* Gram ⊝ Anaerobes
* *Bacteroides*
* *Prevotella*
* *Fusobacterium*
768
Nosocomial Infections:
* intravascular catheters
* erythema, induration, tenderness, and drainage from access sites
* *S. aureus* (including MRSA)
* *S. epidermidis* (long term)
* *Enterobacter*
769
Nosocomial Infections:
* mechanical ventilation
* endotracheal intubation
* new infiltrate on CXR
* ↑ sputum production
* sweet odor
* P. aeruginosa (sweet odor)
* *Klebsiella*
* *Acinetobacter*
* *S. aureus*
770
Nosocomial Infections:
* renal dialysis unit
* needlestick
* HBV
* HCV
771
Nosocomial Infections:
* urinary catheterization
* dysuria
* leukocytosis
* flank pain
* costovertebral angle tenderness
Infections in your **PEcK**er
* ***P**roteus* spp.
* ***E**. **c**oli*
* ***K**lebsiella*
772
Nosocomial Infections:
* water aerosols
* signs of pneumonia
* GI symptoms (diarrhea, nausea, vomiting)
* neurologic abnormalities
*Legionella*
773
Bugs Affecting Unvaccinated Children:
* rash beginning at head and moving down
* postauricular lymphadenopathy
Rubella Virus
774
Bugs Affecting Unvaccinated Children:
* rash beginning at head and moving down
* rash preceded by cough, coryza, conjunctivitis, and blue-white (Koplik) spots on buccal mucosa
Measles Virus
775
Bugs Affecting Unvaccinated Children:
* meningitis
* microbe colonizes nasopharynx
*H. influenzae* type b
776
Bugs Affecting Unvaccinated Children:
* meningitis
* can also lead to myalgia and paralysis
Poliovirus
777
Bugs Affecting Unvaccinated Children:
* epiglottitis
* fever with dysphagia, drooling, and difficulty breathing due to edematous “cherry red” epiglottis
* “thumbprint sign” on x-ray
* also capable of causing epiglottitis in fully immunized children
*H. influenzae* type b
778
Bugs Affecting Unvaccinated Children:
* pharyngitis
* grayish oropharyngeal exudate
* “pseudomembranes” may obstruct airway
* painful throat
* elaborates toxin that causes necrosis in pharynx, cardiac, and CNS tissue
*Corynebacterium diphtheriae*
779
Pathogens:
asplenic patient (due to surgical splenectomy or autosplenectomy, eg. chronic sickle cell disease)
Encapsulated Microbes
* *SHiN**
* **S**. pneumoniae* \>\> ***H**. **i**nfluenzae* type b \> ***N**. meningitidis*
780
Pathogens:
* branching rods in oral infection
* sulfur granules
*Actinomyces israelii*
781
Pathogens:
chronic granulomatous disease
Catalase ⊕ Microbes
* especially *S. aureus*
782
Pathogens:
“currant jelly” sputum
*Klebsiella*
783
Pathogens:
dog or cat bite
*Pasteurella multocida*
784
Pathogens:
* facial nerve palsy (typically bilateral)
* Lyme disease
*Borrelia burgdorferi*
785
Pathogens:
fungal infection in diabetic or immunocompromised patient
*Mucor* or *Rhizopus* spp.
786
Pathogens:
health care provider
* HBV
* HCV (from needlestick)
787
Pathogens:
neutropenic patients
* *Candida albicans* (systemic)
* *Aspergillus*
788
Pathogens:
organ transplant recipient
CMV
789
Pathogens:
* Periodic Acid–Schiff (PAS) ⊕
* Whipple disease
*Tropheryma whipplei*
790
Pathogens:
* pediatric infection
* epiglottitis
*Haemophilus influenzae*
791
Pathogens:
* pneumonia in cystic fibrosis
* burn infection
*Pseudomonas aeruginosa*
792
Pathogens:
* pus
* empyema
* abscess
*S. aureus*
793
Pathogens:
rash on hands and feet
* Coxsackie A Virus
* *Treponema pallidum*
* *Rickettsia rickettsii*
794
Pathogens:
sepsis/meningitis in newborn
Group B Strep
795
Pathogens:
surgical wound
*S. aureus*
796
Pathogens:
traumatic open wound
*Clostridium perfringens*
