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Flashcards in Microbiology Deck (186):
1

Gram positive structure

Cell wall present; major surface antigen

Composition:
- Peptidoglycan
- Lipoteichoic acid--> TNF, IL-1 induction

2

Gram negative structure

No cell wall, only outer membrane
- Site of Endotoxin= LPS (lipopolysaccharide)= major surface antigen

Composition:
- Lipid A--> activate macrophages--> increased TNF and IL-1
- Antigen= O polysaccharide
- Periplasm= space between cytoplasmic membrane and outer membrane; contains hydrolytic enzymes (beta-lactamases)

3

Spore structure

Resistant to dehydration, heat, chemicals
- Must autoclave (121 C for 15 min)

Composition:
- Keratin-like coat
- Dipicolinic acid core
- Peptidoglycan

Seen in:
- Soil: B. anthracis, Clostridium perfringens, c. tetani
- Other: B. cereus, C. botulinum, Coxiella burnetti

4

Gram-positive cocci

Staphylococcus
Streptococcus

5

Gram-negative cocci

Neisseria

6

Gram-positive rod

Clostridium
Corynebacterium
Bacillus
Listeria
Mycobacterium (high lipid= acid fast)
Gardenerella (gram variable)

7

Gram-negative rods

Almost everything else:
1. Enterics:
- E. Coli
- Shigella
- Yersinia
- Klebsiella
- Proteus
- Enterobacter
- Serratia
- Vibrio
- Campylobacter
- Helicobacter (silver stain+)
- Pseudomonas
- Bacteroides

2. Respiratory:
- Haemophilus (pleomorphic)
- Legionella (intracellular; silver stain +)
- Bordetella

3. Zoonotic
- Francisella
- Brucella
- Pasteurella
- Bartonella

** resistant to Penicillin G (gram-negative outer membrane inhibits Pen G/Vanco from entering)
** Susceptible to Ampicillin, amoxicillin

8

Spirochetes

Gram-negative (too thin)
- Leptospira
- Borrelia
- Treponema

9

Pleomorphic bacteria

Giemsa-stain
- Rickettsiae (intracellular)
- Chlamydiae (intracellular, no muramic acid)

10

Bacteria with no cell wall

Mycoplasma= no staining
- Sterols with no wall

11

Giemsa-positive

Certain Bugs Really Try my Patience:
- Chlamydia
- Borrelia
- Rickettsiae
- Trypanosomes
- Plasmodium

12

Carbol Fuschin stain (Ziehl-Neelsen)

Acid-fast organisms
- Nocardia
- Mycobacterium

13

India ink positive

Cryptococcus neoformans
- can also stain with mucicarmine

14

Exotoxin

Derived from gram + and gram -
- Secreted from cell
- Polypeptide
- Located on plasmid/bacteriophage
- Highly toxic
- Antigenic= Induces antitoxins (titer antibodies)
- Vaccine= toxoids
- Destroyed at 60C (besides staph enterotoxin)

Seen in: Tetanus, botulism, diphtheria

15

Endotoxin

LPS= structural component of outer cell membrane in gram negative; released when lysed (NOT secreted)

Activates:
1. Macrophages:
- IL-1--> fever
- TNF--> fever, hypotension
- NO--> hypotension
2. Complement
- C3a--> hypotension, edema
- C5a--> neutrophil chemotaxis
3. Tissue factor
- Coagulation cascade--> DIC

- Located on Bacterial chromosome
- Low toxicity
- Causes: Fever, shock
- Mode of action:Induces TNF and IL-l
- Antigenic: Poorly antigenic
- Vaccines= none
- Stable at 100C for 1 hour

Seen in: meningococcemia, gram-negative sepsis

16

Obligate aerobes

Nagging Pests Must Breathe
- Nocardia
- Pseudomonas aeruginosa
- Mycobacterium tuberculosis (apices of lung)
- Bacillus

17

Obligate anaerobes

Can't Breathe Air
- Clostridium
- Bacteroides
- Actinomyces

Seen in GI tract, pathogenic anywhere else
** Can't treat with aminoglycosides= need O2 to enter cell

18

Obligate intracellulars

Rickettsia
Chlamydia

19

Facultative intracellular

Now Listen Sally, Yer Friend Bruce Must Leave

- Neisseria
- Listeria
- Salmonella
- Yersinia Pestis
- Francisella
- Brucella
- Mycobacterium
- Legionella

20

Encapsulated bacteria

Positive Quellung reaction--> swelling

SHiNE SKiS
- Streptococcus pneumoniae
- Haemophilus infiuenzae type B
- Neisseria meningitidis
- Escherichia coli
- Salmonella
- Klebsiella pneumoniae
- group B Strep.

21

Catalase-positive

Degrades H2O2 before converted to microbicidal products by Myeloperoxidase (MPO)
PLACESS for your cats:
- Pseudomonas
- Listeria
- Aspergillus
- Candida
- E. Coli
- S. Aureus
- Serratia

22

Urease-positive

CHuck norris hates PUNKSS:
- Cryptococcus
- H. pylori
- Proteus
- Ureaplasma
- Nocardia
- Klebsiella
- S. epidermidis
- S. saprophyticus

23

IgA protease

Enzyme cleaving IgA--> colonize respiratory mucosa: SHiN
- S. pneumoniae
- H. influenza (B)
- Neisseria

** These can all take up naked DNA from environment as well= Transformation

24

Protein A

S. Aureus
- Binds Fc region of Ig--> no opsonization/phagocytosis

25

M Protein

Group A strep
- Prevents phagocytosis

26

Pigment-producing bacteria

Actinomyces Israelii= yellow (Israel= yellow sand)

S. Aureus= yellow (pus/gold)

Pseudomonas aeruginosa= blue/green (pyocyanin)

Serratia marcescens= red (maraschino cherry)

27

Novobicin

Used to ID catalase-positive, coagulase-negative staphylococci
- Staph Saprophyticus= resistant
- Staph Epidermis= sensitive

28

Optochin

used to ID catalase-negative alpha-hemolytic streptococci:
- Viridans= resistant
- Penumoniae= sensitive

29

Bacitracin

Used to ID Catalse-negative, beta-hemolytic streptococci:
- Agalactiae= resistant
- Pyogenes= sensitive

30

Alpha-hemolytic bacteria

Partial hemolysis; green ring around colonies
- Strep pneumo
- Strep viridans

31

Beta-hemolytic bacteria

Complete hemolysis; clear ring around colonies:

- Staph aureus
- Strep pyogenes (group A)
- Strep agalctiae (group B)
- Listeria monocytogenes

32

Staphylococcus aureus

Gram positive cocci, Clustered
Catalase positive
Coagulase positive

Virulence factor= Protein A (binds Fc-IgG--> prevents phagocytosis)

Causes:
1. Inflammatory disease: skin infections, organ abscesses, pneumonia
- Acute bacterial endocarditis
- Osteomyelitis

2. Toxin-mediated disease:
- Toxic shock syndrome (TSST-1)= superantigen, binds MHC II receptor--> T-cell activation--> IFN-gamma, IL-2 release
- scalded skin (exfoliative toxin)
- rapid-onset food poisoning (preformed enterotoxins)
** Activates T-cells (IL-2) and macrophages (IL-1, TNF)

3. MRSA: resistant to beta-lactams (altered penicillin-binding protein)

Treatment:
- Nafcillin (Naf for Staph- EXCEPT MRSA)
- Vancomycin for MRSA

THINK:
- Pus, empyema, abscess
- Surgical wound
- chronic granulomatous disease (Catalase-positive microbes)

33

Staphylococcus epidermidis

Gram positive cocci
Catalase positive
Coagulase negative
Novobicin sensitive (vs staph saprophyticus)

Infects prostehetic devices, IV catheters (biofilm)
- Seen in normal skin flora
- Contaminates blood cultures

Resistant to penicillins, tx with Vancomycin

34

Staphylococcus saprophyticus

Gram positive cocci
Catalase positive
Coagulase negative
Novobicin resistant (vs staph epidermidis)

Causes UTIs

35

Streptococcus pneumoniae

Gram positive cocci; lancet shaped
Catalase negative
alpha-hemolytic
Capsule (+ quelling)
Optochin sensitive (vs strep Viridans)
IgA protease

Causes:
- Meningitis
- Otitis media
- Pneumonia (rusty sputum)
- Sinusitis
- Sepsis, splenectomy in Sickle cell

36

Streptococcus viridans

Gram positive cocci
Catalase negative
alpha-hemolytic
No capsule
Optochin resistant (vs strep pneumo)

Causes:
- Dental caries (normal flora in mouth= strep mutans)
- Subacute bacterial endocarditis (strep sanguis)

37

Strep pyogenes

Group A strep
Gram positive cocci
Catalase negative
beta-hemolytic
Bacitracin sensitive (vs strep agalactiae)

M-protein (prevents opsonization--> blocking phagocytosis)

Exotoxin=
1. streptolysin O
- Protein degrades cell membrane (lyse RBCs)- test for ASO antibodies
2. Exotoxin A: brings MHC II and T-cell receptors together--> release IFN-gamma, IL-2 release--> Toxic shock-like syndrome
3. Streptokinase= plasminogen activator (blocks clotting)

Causes:
1. Pyogenic:
- Pharyngitis
- Cellulitis
- Impetigo (precedes glomerulonephritis, pharyngitis)
2. Toxigenic:
- Scarlet fever (spares face, strawberry tongue, throat)
- Toxic shock-like syndrome
- Necrotizing fasciitis
3. Immunologic:
- Rheumatic fever (polyarthritis, carditis, subcutaneous nodules, erythema marginatum, Sydenham's chorea)
- Acute glomerulonephritis
- Post strep glomerulonephritis= deficiency of complement due to fixation in renal tubules

** ASO titer to detect infection (antibodies to streptolysin O)
** Host antibodies to M-protein--> rheumatic fever

38

Strep agalactiae

Group B strep
Gram positive coci
Catalase negative
Beta hemolytic (Produces CAMP factor--> increased hemolysis)
Bacitracin resistant (vs strep pyogenes)
Hippurate test positive

Causes:
- Illnesses mainly seen in babies (due to colonization of vaginal flora): Pneumonia, meningitis, sepsis
** Screen women at 35-37 weeks
- Prophylaxis with penicillin

39

Enterococci

Group D strep
Gram positive cocci
Catalase negative
Non-hemolytic/variable hemolysis
Grows in Bile and 6.5% NaCl

Enterococci faecalis, faecium:
- Penicillin G resistant
- Cause UTI, biliary tract infections, subacute endocarditis
- Vancomycin-resistant strains= nosocomial infection

40

Streptococcus bovis

Group D strep
Gram positive cocci
Catalase negative
Non-hemolytic
Grows in Bile (no NaCl)

Colonizes gut
- Colon cancer patients: subacute endocarditis, bacteremia

41

Corynebacterium diphtheriae

Gram positive rod (club-shaped)

Black colonies in cystine-tellurite agar

Metachromatic (blue and red) granules
AB Exotoxin= (B=binds, A= active--> EF-2)
- B-prophage encoded--> inhibits protein synthesis (ADP-ribosylates elongation factor= EF-2)
- Test= Elek's test

Causes:
- Pseudomembranous pharyngitis (gray-white)
- Lymphadenopathy
- Myocarditis
- Arrhythmias

** Toxoid vaccine= induces production of IgG against exotoxin B (toxin causes disease, not bacteria)

42

Clostridium tetani

Gram-positive rod
Spore-forming
Obligate anaerobe

Exotoxin= Tetanospasmin
- Tetanus toxin--> cleaves neurotransmitter-releasing proteins (SNARE)
- Blocks glycine, GABA release (inhibitory neurotransmitters) from Renshaw cells in spinal cord
- Causes spastic paralysis, trismus (lockjaw), risus sardonicus)

Tx: passive vaccine

43

Clostridium botulinum

Gram-positive rod
Spore-forming
Obligate anaerobe

Exotoxin= botulinum toxin
- Cleaves SNARE proteins (blocking neurotransmitter release)
- Inhibits ACh release at NM junction--> flaccid paralysis
- Adults= ingest preformed toxin
- Babies= spores in honey--> floppy baby)

Tx: passive vaccine

44

Clostridium perfringens

Gram-positive rod
Spore-forming
Obligate anaerobe

Exotoxin= alpha toxin (lecithinase= phospholipase)
- Phospholipase degrades tissue, cell membranes-->
- Causes myonecrosis (gas gangrene)
- Hemolysis

45

Clostridium difficile

Gram-positive rod
Spore-forming
Obligate anaerobe

Exotoxins:
1. Toxin A = enterotoxin binding brushborder of gut)
2. Toxin B = cytotoxin binding enterocytes--> pseudomembranous colitis
- Secondary to antibiotics (clindamycin, ampicillin)

Treatment:
- Metronidazole
- Oral vancomycin

46

Bacillus anthracis

Gram-positive rod
* Polypeptide capsule (D-glutamate containing)
Spore-forming

Exotoxin= anthrax (Edema factor)
- Mimics adenylate cyclase (increased cAMP)
- Calmodulin-dependent adenylate cyclase--> increases cAMP in smooth muscle--> vasodilation (edema), suppressed neutrophil funciton)

Forms:
- Cutaneous--> black eschar (painless ulcer)--> bacteremia, death)
- Pulmonary--> flu-like symptoms--> fever, pulmonary hemorrhage, mediastinitis, shock (Woolsorter's disease)

47

Bacillus cereus

Gram-positive rod
Spore-forming
Obligate aerobe

Enterotoxin= Cereulide
- Food poisoning (enterotoxin in rice= "reheated rice syndrome)
- Emesis: rice, pasta--> N/V in 1-5 hours
- Diarrhea: GI pain, watery, non-bloody in 8-18 hours

48

Listeria Monocytogenes

Gram positive rod
Facultative intracellular
Catalase positive
Beta hemolytic

Forms "actin rockets"--> move cell to cell
- Tumbling motility

Ingested from unpasteurized milk/cheese, deli meats
Causes:
- Amnionitis
- Septicemia
- Spontaneous abortion
- Meningitis in immunocompromised
- Gastroenteritis in healthy (self-limited)

Vaginal transmission
Causes:
- Granulomatosis infantiseptica
- Neonatal meningitis

* Tx= ampicillin

49

Actinomyces

Long, branching filament (resembles fungi)
Gram-positive
Anaerobe
NOT acid-fast
Found in normal oral flora

Causes:
- Oral/facial abscesses that drain--> sinus tracts
- Yellow "sulfur granules"

Tx: Penicillin

50

Nocardia

Long, branching filament (resembles fungi)
Gram-positive
Aerobe
Acid fast
Found in soil

Causes:
- Pulmonary infections in immunocompromised
- Cutaneous infections (post-trauma) in healthy

Tx: Sulfonamides

51

Mycobacterium tuberculosis

Gram-positive rod
Carbol-Fuschin (Ziehl-Neelsen) stain
Acid fast (lipid membrane)
Obligate aerobe (lung apices)
Facultative intracellular
* Cord factor in virulent strain--> TNF-alpha release, inhibited macrophage maturation
* Sulfatides (surface glycolipids) inhibit phagolysosomal fusion

Primary TB:
- Nonimmune host infected--> Ghon complex:
1. Heals (fibrosis)--> immunity/hypersensitivity
2. Progressive lung disease (immune compromised)
3. Severe bacteremia--> Miliary TB
4. Preallergic lymphatic/hematogenous dissemination--> dormant--> reactivate later in life

Secondary TB:
- Partially immune hypersensitized host (adult) reinfected)
1. Fibrocaseous cavitary lesion (upper lobes)
2. Reactivates

Reactivated TB= Extrapulmonary TB
- CNS (parenchymal TB/meningitis in base of brain)
- Vertebral body (Pott's disease)
- Lymphadenitis
- Renal
- GI

Symptoms:
- Fever, night sweats, weight loss, hemoptysis

Tx:
- Prophylaxis= Isoniazid (INH)
- Therapy= Rifampin, Isoniazid, Pyrazinamide, Ethambutol (RIPE for tx)

52

Mycobacteria Kansasii

Gram-positive rod
Carbol-Fuschin (Ziehl-Neelsen) stain
Acid fast (lipid membrane)
Obligate aerobe (lung apices)
Facultative intracellular
* Cord factor in virulent strain--> TNF-alpha release, inhibited macrophage maturation
* Sulfatides (surface glycolipids) inhibit phagolysosomal fusion

Pulmonary TB-like symptoms

53

Mycobacterium avium-intracellulare

Gram-positive rod
Carbol-Fuschin (Ziehl-Neelsen) stain
Acid fast (lipid membrane)
Obligate aerobe (lung apices)
Facultative intracellular
* Cord factor in virulent strain--> TNF-alpha release, inhibited macrophage maturation
* Sulfatides (surface glycolipids) inhibit phagolysosomal fusion

Disseminated non-TB disease in AIDS, resistant to multiple drugs

** Prophylaxis with azithromycin (CD4+ < 50)
Tx: Azithromycin, Rifampin, Ethambutol, Streptomycin

54

Mycobacterium leprae

Gram-positive rod
Carbol-Fuschin (Ziehl-Neelsen) stain
Acid fast (lipid membrane)
Obligate aerobe (lung apices), likes cool temps
Facultative intracellular
* Cord factor in virulent strain--> TNF-alpha release, inhibited macrophage maturation
* Sulfatides (surface glycolipids) inhibit phagolysosomal fusion

Reservoir in USA= armadillos

Causes Leprosy. 2 forms:
1. Lepromatous= lethal
- Communicable
- Low cell-mediated immunity, humoral Th2 response only
Tx: Dapsone, rifampin, clofazimine (2-5 years)


2. Tuberculoid= hypoesthetic hairless skin plaques ("glove and stocking" loss of sensation)
Tx: Dapsone, Rifampin (6 months)

55

Lactose-fermenting enteric bacteria

Gram-negative rods
Grow pink colonies on MacConkey's agar:

Fast fermenter= Lactose in KEE
- Klebsiella
- E. coli
- Enterobacter

Slow fermenter=
- Citrobacter
- Serratia

56

Neisseria Gonococci

Gram-negative diplococci
Ferments Glucose (Gonococci)
Produces IgA proteases
Facultative intracellular

Grown on special agar: Thayer-Martin agar (or VPN agar)—an agar plate containing antibiotics (vancomycin, colistin, nystatin, and TMP-SMX)

- NO vaccine available (rapid antigenic variation in pilus)
- STD

Causes:
- Septic arthritis
- Neonatal conjunctivitis
- PID
- Fitz-Hugh-Curtis syndrome (adhesions due to PID; infection of liver capsule)

Tx: Ceftriaxone (+ azithromycin/doxycyclin for chlamydia coinfection)

57

Neisseria Meningococci

Gram-negative diplococci
Ferments Maltose and glucose (MeninGococci)
Produces IgA proteases
Facultative intracellular
Encapsulated (polysaccharide capsule)

Grown on special agar: Thayer-Martin agar (or VPN agar)—an agar plate containing antibiotics (vancomycin, colistin, nystatin, and TMP-SMX)

- Vaccine (none for Type B)
- Found in respiratory, oral secretions

Causes:
- Meningococcemia
- Meningitis
- Waterhouse-Friderichsen syndrom

Tx: Ceftriaxone, Pen G
** Rifampin, ciprofloxacin, ceftriaxone in close contacts

58

Haemophilus Influenza

Gram negative
Coccoid rods
Requires factor V and X to grow in culture (chocolate agar)
IgA protease
Encapsulated

- Vaccine= type B capsular polysaccharide conjugated to diphtheria toxoid (2-18 months)
- Nontypable strains cause mucosal infections (no vaccine available)

Causes:
- Epiglottitis (cherry red)
- Meningitis
- Otitis media
- Pneumonia

Tx: Ceftriaxone (meningitis)
* Rifampin prophylaxis in close contacts

THINK:
- Pediatric infection (epiglottitis)

59

Legionella pneumophilia

Gram-negative rod
Facultative intracellular
Silver stain
Grown on charcoal yeast extract with iron, cysteine

- Aerosol transmission from water source
- Detected in urine
- Labs show hyponatremia

Causes:
- Legionnaire's disease= severe pneumonia, fever, GI, CNS symptoms
- Pontiac fever= mild flu-like syndrome

Tx: Macrolide (protein synthesis), quinolone (topoisomerase II)

60

Pseudomonas aeruginosa

Gram negative rod (enteric)
Obligate aerobe
Catalase positive
Lactase NON-fermenting
Oxidase positive
Blue-green pigment, grape-like odor

Motile, oxidase positive

Produces:
- Endotoxin (fever, shock)
- Exotoxin A (inactivates EF-2)
- Elastase (breaks down vessel walls)

Causes: PSEUDOmonas
- Pneumonia (chronic in CF pts due to biofilm)
- Sepsis
- External otitis
- UTI
- Drug use
- Osteomyelitis (diabetic/drug user)
+ Hot tub foliculitis, wound/burn infections
+ MEO in diabetics

Tx:
- Aminoglycoside + extended-spectrum penicillin (piperacillin, ticarcillin)

61

Enteroinvasive E. Coli (EIEC)

Gram-negative rod
Lactose fermenting

Virulence factors:
- P fimbriae (cystitis/pyelonephritis)
- K capsule (pneumonia, neonatal meningitis)
- LPS endotoxin (septic shock)

Mechanism:
- Invades intestinal mucosa--> necrosis, inflammation

Manifestation: similar to Shigella
- Invasive
- Dysentery (blood, pus in stool)

62

Enterotoxigenic E. Coli (ETEC)

Gram-negative rod
Lactose fermenting

Virulence factors:
- P fimbriae (cystitis/pyelonephritis)
- K capsule (pneumonia, neonatal meningitis)
- LPS endotoxin (septic shock)

Mechanism:
- Labile toxin: overactivates adenylate cyclase--> increased cAMP--> Cl- secretion in gut--> H20 moves out of cells
- Stable toxin: overactivates guanylate cyclase--> increased cGMP--> decreased resorption of NaCl /H20 in gut
- NO inflammation/invasion

Manifestation: traveler's diarrhea

63

Enteropathogenic E. Coli (EPEC)

Gram-negative rod
Lactose fermenting

Virulence factors:
- P fimbriae (cystitis/pyelonephritis)
- K capsule (pneumonia, neonatal meningitis)
- LPS endotoxin (septic shock)

Mechanism:
- Adheres to apical surface, flattens villi
- Prevents absorption

Manifestation:
- Pediatric diarrhea

64

Enterohemorrhagic E. Coli (EHEC)

Gram-negative rod
Lactose fermenting

Virulence factors:
- P fimbriae (cystitis/pyelonephritis)
- K-1 capsule (pneumonia, neonatal meningitis)
- LPS endotoxin (septic shock)

Mechanism:
- O157:H7= most common--> Shiga-like toxin
- Shiga-like toxin (SLT)= inactivates 60S ribosomal subunit by removing adenine from rRNA
- Endothelial swelling, narrowed lumen--> hemolysis, reduced renal blood flow
- Damaged endothelium--> thrombocytopenia

Cuases:
- Dysentery (Shiga-like)
- Hemolytic-uremic syndrome (HUS) due to cytokine release in response to SLT--> vascular damage--> capillary thrombus formation--> anemia, thrombocytopenia, acute renal failure, increased bleeding time

65

Klebsiella

Gram negative rod
Lactose fermenter
Polysaccharide capsule (mucoid colonies)

4As:
- Aspiration pneumonia
- Abscess (lungs/liver)
- Alcoholics
- diAbetics

* can also cause nosocomial UTI: positive urease test

66

Salmonella

Gram negative rod
Lactose non-fermenter
Oxidase negative
Facultative intracellular
Encapsulated

- Flagellated
- Hematogenous dissemination
- Animal reservoir
- Produce hydrogen sulfide
- Invades intestinal mucosa--> monocytic response

Causes:
- Bloody diarrhea
- Non-typhoidal= appendicitis mimicker
- Typhi= Typhoid fever (humans only): rose spots on abdomen, fever, headache, diarrhea
- Osteomyelitis in sickle cell pts

Tx: Antibiotics prolong symptoms

67

Shigella

Gram negative rod
Lactose non-fermenter
Oxidase negative
Shiga toxin= inactivates 60S ribosomal subunit by removing adenine from rRNA

- No flagella
- Cell to cell transmission
- Reservoir= humans/primates
- Invades intestinal mucosa--> PMN infiltration
- Shiga toxin--> Cytokine release--> HUS: due to cytokine release in response to Shige toxin--> vascular damage--> capillary thrombus formation--> anemia, thrombocytopenia, acute renal failure, increased bleeding time

Tx: antibiotics shortens excretion of organism in feces

68

Campylobacter jejuni

Gram negative comma-shaped
Oxidase positive
Grows at 42C

Transmitted through poultry, meat, unpasteurized milk

Causes:
- Bloody diarrhea (esp. children)
- Guillain-Barre syndrome, reactive arthritis
- Mimics appendicitis

69

Vibrio cholerae

Gram negative comma-shaped
Oxidase positive
Grows in alkaline media

Mechanism:
- Cholera toxin Activates Gs of adenylate cyclase--> increased cAMP--> increased Cl- secretion, H20 efflux

Causes:
- Profuse rice-water diarrhea (common in developing countries)

Tx: rehydration

70

Yersinia enterocolitica

Gram negative rod
Facultative intracellular

Mechanism:
- Transmitted from pet feces, contaminated milk, pork

Causes:
- Mesenteric adentitis (Crohn's, appendicitis mimicker)

71

H. Pylori

Curved Gram-negative rod
Silver stain
Urease positive (urease breath test)- alkaline environment created in stomach

Causes:
- Gastritis
- 90% duodenal ulcers
- Increased peptic ulcer, gastric adenocarcinoma, B-cell lymphoma risk

Tx: triple therapy:
- PPI
- Clarithromycin
- Amoxicillin/ Metronidazole

72

Spirochetes

Borrelia (BIG)= Wright/Giemsa stain
Leptospira
Treponema= dark field microscopy

73

Leptospira interrogans

Spirochete

Water contaminated with animal urine (triathletes in tropics)

Causes:
- Flu-like symptoms
- Jaundice
- Photophobia with conjunctivitis
- Weil's disease= icterohemorrhagic leptospirosis: severe; jaundice, azotemia (liver, kidney dysfunction), fever, hemorrhage, anemia

74

Borrelia Burgdorferi

Spirochete (visualized with Wright/Giemsa stain)

Lyme disease:
- Transmitted by Ixodes tick
- Reservoir= wood mouse
- Stages:
1. Erythemia migrans (bull's eye), flu-like
2. Neurologic (Bell's palsy), cardiac (AV node block)
3. Musculoskeletal (chronic monoarthritis, migratory polyarthritis), neurological (encephalopathy, polyneuropathy), cutaneous

75

Treponema Pallidum

Spirochete
- Visualized by dark-field microscopy
- Screened with VDRL, confirmed with FTA-ABS

Syphillis:
1. Primary: localized painless chancre (treponemes)
2. Secondary: disseminated disease
- Constitutional symptoms
- Maculopapular rash
- Condylomata lata (treponemes found on warty lesions)
3. Tertiary:
- Gummas (chronic granulomas)
- Aortitis (vaso vasorum destruction)
- Neurosyphilis (tabes dorsalis)
- Argyll-Robertson pupil (non-reactive, accomodative)
- Signs: broad-based ataxia, + Romberg, Charcot joint, stroke w/o HTN
- Treponemes in spinal tap

Congenital syphilis:
- Saber shins
- Sadle nose
- CNVII deafness
- Hutchinson's teeth
- Mulberry molars

** VDRL= nonspecific; can also indicate:
- Viruses
- Drugs
- Rheumatic fever
- Lupus, leprosy

Tx: Pen G
- Can lead to Jarisch-Herxheimer reaction (killed bacteria release pyrogens)- administer steroids, low dose antibiotics

76

Bartonella

Cat scratch disease
- Can cause bacillary angiomatosis in immune compromised

77

Borrelia Recurrentis

Recurrent fever

Source: Louse

78

Brucella

Gram negative rod
Facultative intracellular

Causes: Undulent fever

Source: unpasturized dairy

79

Chlamydia psittaci

Obligate intracellular organism (cannot make own ATP)
- Giemsa positive
- Pleomorphic

Elementary body= Enters cell via Endocytosis

Reticulate body= replicates in cell via fission (seen on tissue culture)
- Cytoplasmic inclusions on Giemsa, fluorescent antibody

Psittacosis (pneumonia)

Source: parrots, birds

Tx:
- Azithromycin (one time)
- Doxycycline

80

Coxiella burnetii

Q fever

Source: aerosol of cattle, sheep amniotic fluid
- Survives in soil for years (spore)

Tx: Doxycycline

81

Ehrlichia chaffeensis

Monocyte with morula (berry-like) inclusion in cytoplams

Ehrlichiosis

Source: lone star tick

Tx: Doxycycline

82

Francisella tularensis

Tularemia

Source: ticks, rabbits, deer fly

83

Pasteurella multocida

Cellulitis, osteomyelitis

Source: animal bite (cat, dog)

84

Rickettsia prowazekii

Obligate intracellular
Need CoA and NAD+

Epidemic typhus (pro-WAr)
- Rash sparing palms and soles

Source: louse

Tx: Doxycycline

85

Rickettsia Typhi

Obligate intracellular
Need CoA and NAD+

Endemic typhus

Source: fleas

Tx: Doxycycline

86

Yersinia pestis

Facultative intracellular
Plague

Source: fleas (rats/prairie dogs= reservoir)

87

Gardenerella vaginalis

Gram-variable pleomorphic rod
"Clue cells" on vaginal swab
KOH prep= fishy smell

Causes: Bacterial vaginitis
- Non-painful, smelly
- Not STD (associated with sexual activity)

Tx: Metronidazole

88

Rickettsia Rickettsii

Obligate intracellular
Need CoA and NAD+

Causes:
- Rocky Mountain Spotted Fever (Broad distribution)
- Rash: wrists, ankles--> trunks, palms, soles
- Headache, fever

89

Anaplasma

Anaplasmosis:
Granulocytes with morula in cytoplasm

90

Chlamydia trachomatis

Obligate intracellular organism (cannot make own ATP)
- Giemsa positive
- Pleomorphic

Elementary body= Enters cell via Endocytosis

Reticulate body= replicates in cell via fission (seen on tissue culture)
- Cytoplasmic inclusions on Giemsa, fluorescent antibody

Causes:
Reiter's syndrome:
- Reactive arthritis
- Conjunctivitis
- Nongonococcal urethritis
- PID

Serotypes:
- A, B, C= chronic infection--> follicular conjuntivitis--> blindness (ABC= Africa, Blindness, Chronic infection)
- D-K= Urethritis/PID, ectopic pregnancy, neonatal pneumonia (staccato cough), neonatal conjunctivitis)
- L1, L2, L3= lymphogranuloma

Tx:
- Azithromycin (one time)
- Doxycycline

91

Mycoplasma pneumoniae

No cell wall (no stain)
- Sterol membrane (stability)

Atypical "walking" pneumonia
- Insidious onset, H/A, nonproductive cough, diffuse interstital infiltrate
- IgM titer--> agglutinate, lyse RBCs

Tx: macrolide, fluoroquinolone

92

Bordetella pertussis

Pertussis toxin
- Overactivates adenylate cyclase--> increased cAMP (disables Gi)--> impairs microbial phagocytsosis

Causes:
- Whooping cough= cough on expiration, whoop on inspiration

93

Histoplasmosis

Dimorphic fungi (20C= cold mold, 37C= heat yeast)
- Can mimic TB with no person-person transmission

Location:
- Mississippi, Ohio river valleys
- Bird/bat droppings in CAVES

Causes: pneumonia
- Hilar adenopathy

Histo: Macrophage filled with histo (Histo hides in macrophages)

Tx:
- Local= fluconazole, itraconazole
- Systemic= Amphotericin B

94

Blastomycosis

Dimorphic fungi (20C= cold mold, 37C= heat yeast)
- Can mimic TB with no person-person transmission

Location:
- States East of Mississippi river, Central America

Causes: inflammatory, lung disease
- Disseminates to skin, bone
- Granulomatous nodules

Histo: broad-based budding (Blasto Buds)

Tx:
- Local= fluconazole, itraconazole
- Systemic= Amphotericin B

95

Coccidioidomycosis

Dimorphic fungi (20C= cold mold, 37C= heat SPHERULE)
- Can mimic TB with no person-person transmission

Location:
- SW USA, California (Valley fever)

Causes: pneumonia, meningitis
- Disseminate to skin, bone
- Increased cases after earthquakes

Histo: Spherule filled with endospores (larger than RBC)
- Coccidio crowds

Tx:
- Local= fluconazole, itraconazole
- Systemic= Amphotericin B

96

Paracoccidioidomycosis

Dimorphic fungi (20C= cold mold, 37C= heat yeast)
- Can mimic TB with no person-person transmission

Location: Latin America (Paracoccdio parasails with Captain's wheel all the way to Latin America)

Histo:
- Budding yeast, captain's wheel formation

Tx:
- Local= fluconazole, itraconazole
- Systemic= Amphotericin B

97

Tinea Versicolor

Malassezia furfur
- Lipid degradation--> acids--> malanocyte damage--> hypo/hyperpigmented areas
- Seen in hot, humid weather

Histo:
- "spaghetti and meatball" on KOH

Tx:
- Topical miconazole
- Selenium sulfide (Selsun Blue)

98

Candida albicans

Tx:
- Topical azole for vaginal infection
- Fluconazole/capsofungin for oral/esophageal
- Fluconazole, ampho B, caspofungin for systemic tx

99

Aspergillus Fumigatus

Invasive= immunocompromised, chronic granulomatous disease

Allergic broncopulmonary (ABPA)= Asthma, CF

Aspergillomas in lung cavities (post-TB)

** Produce aflatoxins= associated with Hepatocellular carcinoma

100

Cryptococcus neoformans

Encapsulated (crypt) yeast
- Found in soil, pigeon droppings
- Inhaled, hematogenous dissemination to meninges

Culture:
- Sabouraud's agar
- India Ink stain
- Latex agglutination= polysaccharide capsular antigen

Can cause meningitis ("soap bubble lesions" in brain) in immune-compromised (AIDS patients with CD4+ < 50)

Tx:
- Amphotericin B + Flucytosine

101

Pneuomcystis jirovecii

PCP= diffuse interstitial pneumonia
- bilateral CXR
- Dx= biopsy, lavage
- Disc-shaped yeast on methenamine silver stain

Tx: TMP-SMZ, pentamidine, dapsone
- Prophylax with CD4+ < 200

102

Sporothrix schenckii

Dimorphic
Cigar-shpaed budding yeast

"Rose-pickers" thumb= pustule, ulcer with nodules along lymphatic drainage

Tx: itraconazole, potassium iodide (plant a rose in the pot)

103

Giardia Lamblia

Trophozoite

Giardiasis: bloating, flatulence, foul-smelling, fatty diarrhea

Transmission: cysts in water

Dx: stool: trophozoites, cysts

Tx: Metronidazole (GET on the Metro: G= giardia, E= entamoeba, T= Trichomonas)

104

Entamoeba histolytica

Trophozoite

Amebiasis: bloody diarrhea (dysentery), liver abscess (anchovy paste exudate), RUQ pain (flask-shped ulcer if submucosal colon abscess ruptures)

Transmission: cysts in water

Dx: Serology, trophozoites (with phagocytosed RBCs) or cysts (multinucleated) in stool

Tx: Metronidazole (GET on the Metro: G= giardia, E= entamoeba, T= Trichomonas)
- Iodoquinol for asymptomatic carriers

105

Cryptosporidium

AIDS patients: severe diarrhea
- Milder (watery diarrhea) in immunocompetent

Transmission: Cysts in water)

Dx: Cysts on acid-fast stain

Tx: Prevent (filter water)
- Nitazoxamide in immunocompetent

106

Toxoplasma Gondii

HIV: brain abscess (ring-enhancing lesions)
Congenital: Triad= chorioretinitis, hydrocephalus, intracranial calcifications

Transmission: cysts in meat, cat feces

Dx: Serology, biopsy

Tx: Sulfadiazine, pyrimethamine

107

Naegleria Fowleri

Rapidly fatal meningoencephalitis

Transmission: swimming in freshwater lakes, Netti pot (cribiform plate--> brain)

Dx: Amoebas in CSF

Tx: Amphotercin (maybe?)

108

Trypanosoma brucei gambiense

West African Sleeping sickness:
- Slowly progressive fevers, wasting, late neuro symptoms
- Recurrent fevers: due to Variable Surface Glycoproteins (change with each generation--> immune system can't keep up)

Transmission: Tsetse fly (painful bite)

Diagnosis: blood smear

Tx:
Blood borne= Suramin
CNS= Melarsoprol
"Sure is nice to go to sleep. Melatonin helps with sleep"

109

Trypanosoma brucei rhodesiense

East African sleeping sickness:
- More severe, rapid progression (recurrent fevers--> neurological disease--> coma--> death)

Transmission: Tsetse fly (painful bite)

Diagnosis: blood smear

Tx:
Blood borne= Suramin
CNS= Melarsoprol

110

Plasmodium vivax/ovale

Malaria: fever, H/A, anemia, splenomegaly
- 48 hr cycle (fever on 1st, 3rd day)
- Dormant form in liver

Transmission: Mosquito

Diagnosis: Blood smear
- Trophozoite ring
- RBC schizont with merozoites

Tx:
- Chloroquine (blocks heme ploymerase)
- Mefloquine for resistant strains
- Life-threatening: IV quinidine (test for G6PD)
- **Add primaquine (test for G6PD) to kill hypnozoites in liver

111

Plasmodium falciparum


Malaria: fever, H/A, anemia, splenomegaly
- Severe, irregular fever
- Parasitized RBCs occlude brain capillaries--> cerebral malaria, kidneys, lungs

Transmission: Mosquito

Diagnosis: Blood smear
- Trophozoite ring
- RBC schizont with merozoites

Tx:
- Chloroquine (blocks heme ploymerase)
- Mefloquine for resistant strains
- Life-threatening: IV quinidine (test for G6PD)

112

Plasmodium malariae

Malaria: fever, H/A, anemia, splenomegaly
- 72 hour cycle of fever

Transmission: Mosquito

Diagnosis: Blood smear
- Trophozoite ring
- RBC schizont with merozoites

Tx:
- Chloroquine (blocks heme ploymerase)
- Mefloquine for resistant strains
- Life-threatening: IV quinidine (test for G6PD)

113

Babesia

Babesiosis: fever, hemolytic anemia
- Seen in NE USA
- Increased risk of severe disease in asplenia

Transmission: Ixodes tick

Diagnosis: blood smear (ring form, "Maltese cross), PCR

Tx: Atovaquone + azithromycin

114

Trypanosoma cruzi

Chagas' disease: dilated cardiomyopathy, megacolon, megaesophagus

Transmission: Reduviid bug ("kissing bug")- painless bite--> feces enter wound

Diagnosis: Blood smear

Tx: Nifurtimox

115

Leishmania donovani

Visceral leishmaniasis: spiking fevers, hepatosplenomegaly, pancytopenia

Transmission: sandfly

Diagnosis: macrophages with amastigotes

Tx: sodium stibogluconate

116

Trichomonas Vaginalis

Vaginitis: foul-smelling, greenish discharge
- Itching, burning

Transmission: sexual (must have host- no cyst form)

Diagnosis: Trophozoites (motile) on wet mount
- Strawberry cervix

Tx: Metronidazole (patient and partner) (GET on the Metro: G= giardia, E= entamoeba, T= Trichomonas)

117

Enterobius Vermicularis

Pinworm
Intestinal infection--> anal pruritis ("Scotch tape test")

Transmission: food contaminated with eggs

Tx: Bendazoles, pyrantel pamoate ("Bendy" worms)

118

Ascaris Lumbricoides

Giant roundworm
Intestinal infection

Transmission: Fecal-oral; see eggs under microscope

Tx: Bendazoles, pyrantel pamoate

119

Strongyloides stercoralis

Intestinal infection: N/V, diarrhea, anemia

Transmission: **larvae in soil penetrate skin**

Tx: Albendazole, ivermectin

120

Ancylostoma duodenale, Necator Americanus

Old world, new world hookworm
Intestinal infection--> anemia (suck blood) (microcytic anemia)

Transmission: **larvae penetrate skin**

Treatment: Bendazoles, pyrantel pamoate

121

Dranunculus medinensis

Skin inflammation, ulceration

Transmission: drinking water

Tx: slow extraction of worm

122

Onchocerca volvulus

"River blindness": microfilariae migrate to eye--> die--> inflammatory response--> opacity
- Hanging groin
- Lymphadenopathy
- Allergic reactions

Transmission: Female black fly

Tx: Ivermectin (Iver for River blindness)

123

Loa Loa

Swelling in skin, pain and edema in eye (worm in conjunctiva)

Transmission: female deer fly (horse, mango fly)

Treatment: Diethycarbamazine

124

Wucheria bancrofti

Blocks lymphatic drainage--> elephantiasis (~1 year after bite)

Transmission: female mosquitoes (night)

Tx: Diethylcarbamazine

125

Toxocara canis

Visceral larval migrans: granulomas in viscera (including CNS)--> death from respiratory failure, cardiac arrhythmias, brain damage

Transmission: food contaminated with eggs (carried by cats, dogs)

Tx: Albendazole, mebendazole

126

Taenia Solium

Cestode (tapeworm)
1. Ingestion of larvae in undercooked pork--> Intestinal infection

Tx: Praziquantel

2. Ingestion of eggs (fecal-oral)--> Cysticercosis, neurocysticercosis

Tx: Praziquantel, bendazoles for neurocysticercosis

127

Diphyllobothrium latum

Cestode (tapeworm)
Vitamin B12 deficiency (tapeworm competes for B12 in intestine)--> anemia

Transmission: Ingestion of larvae from raw freshwater fish

Treatment: Praziquantel

128

Echinococcus granulosus

Cestode (tapeworm)
Ingestion of eggs (dog feces)

Cysts in liver (anaphylyaxis if released--> pretreat with ethanol injection before removing)

Tx: Bendazoles

129

Schistosoma

Trematode
- Liver and spleen granulomas, fibrosis, inflammation
** S. haematobium--> SCC of bladder
** S. Mansoni--> portal HTN

Transmission: Snails= host--> cercariae penetrate skin

Tx: praziquantel

130

Clonorchis sinensis

Trematode= Chinese liver fluke
- Biliary tract inflammation--> pigmented gallstones
* Associated with cholangiocarcinoma

Transmission: undercooked fish

Tx: Praziquantel

131

Paragonimus Westermani

Trematode
- Lung inflammation; secondary bacterial infection--> hemoptysis

Transmission: undercooked crab meat

Tx: Praziquantel

132

Live, attenuated vaccines

Smallpox
Yellow fever
Chicken pox (VZV)
Sabin's polio virus
MMR (only one can be given to HIV+ patients without immune deficiency)
Influenza (flumist nasal spray)

133

Killed vaccines

Rabies
Influenza
Salk Polio
HAV

134

Recombinant vaccine

HBV: antigen= recombinant HBsAg
HPV: 6, 11, 16, 18

135

RNA viral genomes

* All are ssRNA except Reoviridae

* All replicate in cytoplasm except Retrovirus (diploid ssRNA), influenza

+ ssRNA:
I went to a RETRO(virus) TOGA(virus) party, where I drank FLAVored(flavivirus) CORONA(virus) and ate Hippy(hepevirus) CALIfornia (calcivirus) PICkles (picornavirus)

136

DNA viruses

All dsDNA, linear, icosahedral, replicate in nucleus:

Hepadna (circular, incomplete)
Herpes
Adeno
Pox (complex, has DNA-dependent RNA polymerase--> replicates in cytoplasm)
Parvo (ssDNA)
Papilloma (circular, supercoiled)
Polyoma (circular, supercoiled)

137

Herpesviruses

Enveloped
dsDNA, linear

HSV1= oral, Spontaneous temporal lobe encephalitis, keratoconjunctivitis
HSV2= genital
HSV3= VZV= chickenpox
HSV4= EBV= mono, Burkitt's, Hodgkin's, nasopharyngeal carcinoma
HSV5= CMV= AIDS retinitis, congenital defects (latent in mononuclear cells= "owl's eyes")
HSV6= roseola
HHV7= roseola (less common)
HHV8= Kaposi's sarcoma

Diagnosis:
1. PCR (#1)
2. Tzanck test= smear of opened vesicle (used for HSV1, 2, VZV)
- See **intranuclear Cowdry A inclusions**
3. Monospot (EBV): heterophile antibodies on agglutination of sheep/horse RBCs
- Atypical lymphocytes= reactive cytotoxic T cells

138

Hepadnavirus

Enveloped
dsDNA, partial circular

Hep B:
- Acute or chronic (incubation= months)
- Vaccine= recombinant (HBsAg)
- Contains reverse transcriptase (NOT retrovirus)= DNA-dependent DNA polymerase
- Uses host RNA polymerase--> viral proteins

Transmission: Parenteral, sexual, maternal-fetal

Serology:
- HBsAg= infected (acute/chronic)
- Anti-HBs= immunity (vaccine/recovered)
- HBcAg= antigen to core (infected)
- Anti-HBc= positive during infection (IgM= acute/recent, IgG= prior/chronic)
- HBeAg= Active (acute/chronic)
- Anti-HBe= Window, chronic (low infectivity, recovery)

** Risk of HCC
** ALT > AST (vs alcoholics: AST > ALT

139

Adenovirus

Non-enveloped
dsDNA, linear

Pharyngitis, hemorrhagic cystitis
Pneumonia
Conjunctivitis

140

Parvovirus

Non-enveloped
ssDNA, linear negative (smallest DNA virus)

B19= "slapped cheeks" (erythema infectiosum), 5th disease
- In SC pts--> aplastic crisis
- In uteros--> hydrops fetalis
- Adults: RBC aplasia, RA symptoms

141

Papillomavirus

Non-enveloped
dsDNA, circular

HPV:
1, 2, 6, 11= warts
16, 18= CIN, cervical cancer
** Recombinant vaccine

Diagnosis:
- Koilocytes on Papanicolaou smear (pap smear)

142

Polyomavirus

Non-enveloped
dsDNA, circular

- JC virus= PML in HIV
- BK virus= transplant patients, kidney targeted (Bad Kidney)

143

Poxvirus

Enveloped
dsDNA, linear (largest DNA virus)

Smallpox= germ warfare
Vaccinia= cowpox
Molluscum contagiosum= flesh-dome lesion with central dimple

144

Reovirus

Nonenveloped
dsRNA, linear
Icosahedral

Coltavirus= colorado tick fever (arbovirus)

Rotavirus:
- villus destruction, atrophy--> decreased Na absorption, loss of K+

145

Picornavirus

Non-enveloped
ssRNA+, linear
Icosahedral

PERCH:
Poliovirus
Echovirus (aseptic meningitis)
Rhinovirus (common cold)
Coxsackievirus (aseptic meningitis, herpangina, hand foot mouth disease, myocarditis)
HAV (acute Hep A virus): asymptomatic, acute, alone (no carriers)

** All but Rhino (acid-labile) are fecal-oral enteroviruses

146

Hepevirus

Non-enveloped
ssRNA+, linear
Icosahedral

Hep E
- Transmission= fecal-oral (waterborne epidemics)
- No carrier state, short incubation, no HCC
- Enteric, Expectant mothers (bad), Epidemic

147

Calcivirus

Non-enveloped
ssRNA+, linear
Icosahedral

Norovirus

148

Flavivirus

Enveloped
ssRNA+, linear
Icosahedral

Hep C:
- Transmission= blood, IVDU, post-transfusion
- Long incubation
- HCC risk
- Chronic, Cirrhosis, Carcinoma, Carrier

Yellow fever (arbovirus): fever, black vomit, jaundice

Dengue (arbovirus)

St. Louis Encephalitis (arbovirus)

West Nile (arbovirus)

149

Togavirus

Enveloped
ssRNA+, linear
Icosahedral

Rubella (German measles)
- Postauricular lymphadenopathy, arthralgias, truncal rash (head--> trunk)
- Mild in children, serious congenital disease

Eastern Equine Encephalitis (arbovirus)
Western Equine Encephalitis (Arbovirus)

150

Retrovirus

Enveloped
ssRNA+, linear
Icosahedral (HTLV--> T-cell leukemia)
Complex conical (HIV--> AIDS)

** contain reverse transcriptase

HIV:
* envelope proteins acquired by budding from host plasma membrane= ENV
- Env glycosylation--> gp160--> cleaved in ER/golgi--> gp120, gp41
1. gp120= docking glycoprotein*;
- attach to host CD4+ cell (early= CCR5, late= CXCR4)
- attach to CCR5/CD4 on host macrophages
- CCR5 mutation--> immunity (homo), slow course (hetero)
2. gp41= transmembrane protein*; fusion and entry
3. p17= matrix protein
4. p24= capsid protein: GAG
5. reverse transcriptase: POL

Diagnosis:
1. ELISA= rule out (high false-positive)
2. Western Blot= rule in (high false-negative)
3. PCR for viral load
4. CD4+ count (< 200= AIDS) or CD4/CD8 < 1.5

151

Coronaviruses

Enveloped
ssRNA+, linear
Helical

Corona= common cold, SARS

152

Orthomyxoviruses

Enveloped
ssRNA- , linear, 8 segmented
Helical

Influenza:
- Hemagglutin= viral entry
- Neuraminidase= progeny virion release
- Genetic shift/antigenic shift= pandemics (high frequency recombination) ex: swine and human virus recombine
- Genetic drift= epidemics (minor, random mutation)

153

Paramyxovirus

Enveloped
ssRNA-, nonsegmented
Helical

Parainfluenza (croup)

RSV (bronchiolitis in babies, Rx= Ribavirin)

Measles:
- Cough--> conjunctivitis-> spots--> Maculopapular rash: head to toe
- Koplik spots (buccal mucosa)
- Delayed encephalitis (SSPE)
- Giant cell pneumonia (immune suppressed)

Mumps: (makes your parotids and testes as big as POM poms)
- Parotitis
- Orchitits
- Meningitis

** surface F (fusion) protein= respiratory epithelial cells fuse--> multinucleated cells
- Use Palivizumab (MAB against F) to prevent RSV in premies)

154

Rhabdovirus

Enveloped
ssRNA-, linear
Helical

RABIES!:
- Bullet-shaped
- Negri bodies= cytoplasmic inclusions in neurons (Purkinje of Cerebellum)
- Post-exposure prophylaxis= Wound cleansing + Rabies Ig
- Bite--> nerve axons--> CNS--> salivary glands

155

Filovirus

Enveloped
ssRNA-, linear
Helical

Ebola/Marburg hemorrhagic fever

156

Arenaviruses

Enveloped
ssRNA-, circular segments
Helical

Lymphocytic Choriomeningitis Virus (LCMV)
Lassa Fever encephalitis (mouse-borne)

157

Bunyaviruses

Enveloped
ssRNA-, circular segmets
Helical

California encephalitis (Arbovirus)
Sandfly/Rift valley fever (Arbovirus)
Crimean-Congo hemorrhagic fever (Arbovirus)
Hantavirus--> hemorrhagic fever, pneumonia

158

Delta virus

Enveloped
ssRNA-, cricular

Hep D:
Defective (needs HBV for coinfection)
- Transmission: parenteral, sexual, maternal-fetal
- Short superinfection, long coinfection

159

Negative stranded viruses

Must transcribe negative strand to positive:
Always Bring Polymerase Or Fail Replication
- Arenavirus
- Bunyavirus
- Paramyxovirus
- Orthomyxovirus
- Filovirus
- Rhabdovirus

160

Segmented viruses

RNA viruses: BOAR
- Bunyaviruses
- Orthomyxoviruses
- Arenaviruses
- Reoviruses

161

Systemic symptoms of HIV infection

Histoplasma capsulatum (pulm symptoms only in immune competent): low grade fever, hepatosplenomegaly, tongue ulcer
- CD4 < 100
- Oval yeast cells in macrophages

162

Dermatologic symptoms of HIV infection

C. albicans (thrush): cottage-cheese lesions
- oral: CD4 < 400
- esophageal: CD4< 100
- Pseudohyphae

Bartonella henselae: superficial vascular proliferation
- Neutrophilic inflammation

163

GI symptoms of HIV

Cryptosporidium: chronic watery diarrhea
- CD4 < 200
- Acid-fast cysts in stool

164

Neurologic symptoms of HIV

JC virus: encephalopathy
- CD4 < 200

Toxoplasma: abscesses
- CD4 < 100

Cryptococcus neoformans: Meningitis
- CD4 < 50

CMV: Retinitis
- CD4 < 50

Dementia due to HIV

165

Oncologic processes in HIV

HHV8: Kaposi's sarcoma
- Lymphocytic inflammation

EBV:
1. hairy leukoplakia (tongue);
2. non-Hodgkin's lymphoma (large cell)- seen on Waldeyer's ring
3. CNS lymphoma (focal or multiple)

HPV: Squamous cell carcinoma (anus, cervix)

166

Respiratory processes in HIV

CMV: Interstitial pneumonia
- Owl's eye intranuclear inclusions

Aspergillus: invasive
- pleuritic pain, hemoptysis, infiltrate on imaging

Pneumocystis jirovecii: Pneumonia
- CD4 < 200

Mycobacterium aviium intracellulare: TB-like
- CD4 < 50
- Prophylax with azithromycin

167

CD4 < 200

1. Pneumocystis jirovecii: Pneumonia
2. JC virus: encephalopathy
3. Cryptosporidium: chronic watery diarrhea

168

CD4 < 100

1. C. albicans (esophageal thrush): cottage-cheese lesions
2. Toxoplasma: abscesses
3. Histoplasma capsulatum (pulm symptoms only in immune competent): low grade fever, hepatosplenomegaly, tongue ulcer

169

CD4 < 50

1. CMV: Retinitis
2. Cryptococcus neoformans: Meningitis

170

Prion diseases

PrPc= normal cellular prion protein
PrPsc= Beta-pleated form; transmissible
- Accumulation--> spongiform encephalopathy (dementia, ataxia, death)

Creutzfeld-Jacob= sporadic, rapidly progressive dementia

Gerstmann-Straussler-Scheinker= inherited

Acquired= Kuru, New Variant CJD

171

Normal flora in body

Skin= staph epidermidis
Nose= staph epidermidis, colonized by s. aureus
Oropharynx= viridans group strep
Dental plaque= strep mutans
Colon= Bacteroides fragilis > e. coli
Vagina= lactobacillus; colonized by e. coli and group B strep

172

Bugs causing food poisoning

Vibrio parahaemolyticus, vulnificus= contaminated seafood (wounds for vulnificus)
Bacillus cereus= reheated rice
S. aureus= meats, mayonnaise, custard; preformed toxin
Clostridium perfringens= reheated meat
C. botulinum= improperly canned food
E. coli= undercooked meat (O157:H7)
Salmonella= poultry, meat, eggs

173

Bloody diarrhea

Campylobacter
Salmonella
Shigella
EHEC
EIEC
Yersinia enterocolitica
Entamoeba histolytica

174

Watery diarrhea

ETEC (Stable and Labile toxins)
Vibrio
C. Diff (can also have blood)
C. perferingens
Protozoa (giardia, crypto)
Noro, Rotavirus

175

Common causes of pneumonia neonates

Group B strep
E. coli

176

Common causes of pneumonia: children

RSV/ viruses
Mycoplasma
Chlamydia trachomatis
C. pneumoniae
Streptococcus pneumonia

"Runts May Cough Chunky Sputum"

177

Common causes of pneumonia: adults 18-40

Mycoplasma
C. pneumoniae
S. pneumoniae

178

Common causes of pneumonia: adults 40-65

S. pneumoniae
H. influenzae
Anaerobes
Viruses
Mycoplasma

179

Common causes of pneumonia: elderly

S. pneumoniae
Influenza
Anaerobes
H. influenzae
Gram-negative rods

180

Common causes of meningitis: newborns

Group B strep
E. coli
Listeria

181

Common causes of meningitis: children (6 months-6 years)

Strep pneumo
N. meningitidis
H. flu type B
Enteroviruses

182

Common causes of meningitis in 6-60 year olds

S. pneumo
N. meningitidis
Enteroviruses
HSV

183

Common causes of meningitis in 60+ years

S. pneumo
Gram-negative rods
listeria

184

Meningitis: CSF findings

Bacterial= normal pressure, PMNs, increased protein, decreased sugar

Fungal/TB= normal pressure, Lymphocytes, increased protein, decreased sugar

Viral= normal pressure, lymphocytes, normal/elevated protein, normal sugar

185

UTI findings

Predisposition:
- Women (10x more common)
- Males= congenital defects in infants, vesicoureteral reflux
- Elderly males= enlarged prostate

Diagnostics:
- Bacterial UTI= positive leukocyte esterase
- Gram-negative UTI= positive nitrite test

Causes:
1. E. coli
2. Staph saprophyticus
3. Klebsiella pneumoniae (urease positive)
- Serratia marascens= nosocomial, drug resistant
- Enterobacter cloacae= nosocomial, drug resistant
- Proteus mirabilis= motile, "swarm" in agar; urease positive--> struvite stones
- Pseudomonas= nosocomial, drug resistant

186

ToRCHeS

Toxoplasma:
- triad: chorioretinitis, hydrocephalus, intracranial calcifications

Rubella:
- triad: Septal defects/PDA/pulmonary artery hypoplasia or stenosis, cataracts, deafness (+/- "blueberry" rash)

CMV:
- Hearing loss, seizures, petechial rash, "blueberry" rash

HIV:
- Recurrent infections, chronic diarrhea

Herpes Simplex Virus 2:
- Encephalitis, herpetic lesions

Syphillis:
- Stillbirth, hydrops fetalis, facial abnormalities (Hutchinson's teeth, saddle nose, short maxilla), saber shins, deafness (CNVIII)