2. Bacteria

Question 1

Gram (+) | Rods | ?

Answer 1

Clostridium (anaerobe) Corynebacterium Listeria Bacillus

Question 2

Gram (+) | Cocci | Catalase (+), in clusters (Staphylococcus) | Coagulase (+) | ?

Answer 2

Staphylococcus aureus

Question 3

Gram (+) | Cocci | Catalase (+), in clusters (Staphylococcus) | Coagulase (-) | ?

Answer 3

Novobiocin sensitive: Staphylococcus epidermidis Nobobiocin resistant: Staphylococcus saprophyticus

Question 4

Gram (+) | Cocci | Catalase (-), in chains (Streptococcus) | partial hemolysis (green - alpha hemolysis) | ?

Answer 4

(+) Quellung (has capsule), Optochin sensitive, Bile soluble: Streptococcus pneumoniae (-) Quellung (no capsule), Optochin resistant, not bile soluble: Streptococcus viridans

Question 5

Gram (+) | Cocci | Catalase (-), in chains (Streptococcus) | Complete hemolysis (clear, beta-hemolysis) | ?

Answer 5

Bacitracin sensitive: Group A Strep (GAS) aka Streptoccus pyogenes Bacitracin resistant: Group B strep aka Streptococcus agalactiae

Question 6

Gram (+) | Cocci | Catalase (-), in chains (Streptococcus) | No hemolysis (gamma hemolysis) | ?

Answer 6

Enterococcus (E. faecalis) Peptostreptococcus (anaerobe)

Question 7

Identifying Staphylococci w/ Novobiocin (once you know it’s a G(+)/catalase(+) coccus in clusters)

Answer 7

NO vobiocin - S aprophyticus is R esistant; E pidermidis is S ensitive On the office’s staph retreat, there was NO S tRES

Question 8

Identifying Streptococci (once you know it’s a G(+)/catalase(-) coccus in chains)

Answer 8

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 )

Question 9

alpha-hemolytic bacteria

Answer 9

Form a green ring around colonies on blood agar. Include: 1.) Streptococcus pneumoniae (catalase (-) and optochin sensitive) 2.) viridans streptococci (catalase (-), optochin resistant)

Question 10

Beta-hemolytic bacteria

Answer 10

Form a clear area of hemolysis on blood agar. Include: 1.) Staphylococcus aureus (catalase and coagulase positive) 2.) Streptococcus pyogenes - GAS (catalase negative and bacitracin sensitive) 3.) Streptococcus agalactiae - GBS (catalase negative and bacitracin resistant) 4.) Listeria monocytogenes (tumbling motility, meningitis in newborns, unpasteurized milk)

Question 11

Catalase

Answer 11

Catalase degrades H2O2, an antimicrobial product of PMNs. H2O2 is a substrate for myeloperoxidase.

Question 12

Catalase/Coagulase in G(+) cocci

Answer 12

Staphylococci make catalase, whereas Streptococci do not S. aureus makes coagulase, whereas S. epidermidis and S. saprophyticus do not. (Staph make catalase b/c they have more staff. Bad staph (aureus, b/c epidermidis is skin flora) make coagulase and toxins.)

Question 13

Protein A (virulence factor)

Answer 13

Virulence factor of Staphylococcus aureus Binds Fc-IgG, inhibiting complement fixation and phagocytosis

Question 14

TSST (@ molecular level)

Answer 14

In Staph aureus A superAg that binds MHCII and the TCR, resulting in polyclonal T-cell activation

Question 15

Dzs caused by Staphylococcus aureus

Answer 15

1.) Inflammatory Dz - skin infxns, organ abcesses, pneumonia 2.) Toxin-mediated dz - Toxic shock syndrome (TSST-1), scalded skin syndrome (exfoliative toxin), rapid-onset food poisoning (pre-formed enterotoxins) 3.) MRSA (methicillin-resistant S. aureus) infxn: important cause of serious nosocomial and community-acquired infxns. Resistant to beta-lactams due to altered penicillin-binding proteins. 4.) Misc. - acute bacterial endocarditis, osteomyelitis

Question 16

Staphylococcus epidermidis

Answer 16

Infects prosthetic devices and catheters. Component of normal skin flora. Contaminates blood cultures.

Question 17

Streptococcus pneumoniae (the pneumococcus)

Answer 17

Encapsulated. Has IgA protease. Most common cause of: Meningitis Otitis media (in children) Pneumonia Sinusitis (S. pneumoniae MOPS are M ost OP tochin S ensitive) Associated w/ rusty sputum, sepsis in sickle cell anemia and splenectomy.

Question 18

Viridans group Streptococci

Answer 18

Alpha-hemolytic. Normal flora of the oropharynx. Cause dental caries (S. mutans) and subacute bacterial endocarditis (S. sanguis). Resistant to optochin, differentiating them from S. pneumoniae, which is alpha-hemolytic but optochin sensitive. (Viridans group strep live in the mouth b/c they are not afraid of-the-chin <–op-to-chin resistant)

Question 19

Diseases caused by Streptococcus pyogenes (GAS)

Answer 19

1.) Pyogenic - pharyngitis, cellulitis, impetigo 2.) Toxigenic - Scarlet fever, toxic shock syndrome 3.) Immunologic - rheumatic fever, acute glomerulonephritis PH aryngitis gives you rheumatic PH ever and glomerulonePH ritis No rheum for SPECCulation: Subcutaneous nodules, Polyarthritis Erythema marginatum Chorea Carditis

Question 20

Ab’s and Streptococcus pyogenes (GAS)

Answer 20

Ab’s to M protein enhance host defenses againt GAS but can give rise to rheumatic fever. ASO titer detects recent GAS infxn.

Question 21

Streptococcus agalactiae (GBS)

Answer 21

Bacitracin resistant Beta-hemolytic Causes: Pneumonia meningitis Sepsis (mainly in babies) B is for Babies!

Question 22

Enterococci

Answer 22

include Enterococus faecalis and E. faecium) Penicillin G resistant. Cause UTI and subacute endocarditis. Enterococci are hardier than nonenterococcal group D, thus can grow in 6.5% NaCl. Variable hemolysis.

Question 23

Lancefield group D

Answer 23

Includes enterococci and nonenterococcal group D streptococci. Lancefield grouping is based on differences in the C carbohydrate on the bacterial cell wall.

Question 24

VRE

Answer 24

Vancomycin-resistant Enterococci: an important cause of nosocomial infxn.

Question 25

Streptococcus bovis

Answer 25

Highly associated w/ colon cancer. One of the group D streptococci.

Question 26

Diphtheria

Answer 26

Caused by Corynebacterium diphtheriae via an exotoxin encoded by beta-prophage. Potent exotoxin inhibits protein synthesis via ADP ribosylation of EF-2. Sx include: pseudomembranous pharyngitis (grayish-white membrane) w/ lymphadenopathy. Lab Dx based on G(+) rods w/ metachromatic granules. Corynebacterium diphtheriae grows on tellurite agar. ABCDEFG ADP ribosylation Beta-prophage Corynebacterium Diphtheriae Elongation Factor 2 Granules

Question 27

Bacterial spores

Answer 27

Certain G(+) rods form spores when nutrients are limited (@ the end of stationary phase) Spores are highly resistant to destruction by heat and chemicals. Have dipiclonic acid in their core. Have no metabolic activity. Must autoclave to kill spores.

Question 28

Important spore-forming bacteria

Answer 28

G (+) spores found in soil: Bacillus anthracis Clostridium perfringens C. tetani Other spore formers: B. cerus C. botulinum

Question 29

Clostridia (generally)

Answer 29

G(+) Spore-forming Obligate anaerobic Bacilli

Question 30

Clostridium tetani

Answer 30

produces the exotoxin that causes tetanus TETanus is TETanic paralysis (blocks glycine release [an inhibitory NT]) from Renshaw cells in spinal cord

Question 31

Clostridium botulinum

Answer 31

produces preformed, heat-labile toxin that inhibits ACh release at the NMJ, causing botulism (flaccid paralysis). In adults, dz is caused by ingestion of preformed toxin. In babies, ingestion of bacterial spores in honey causes dz (floppy baby syndrome). BOTulinum is from bad BOTtles of food and honey.

Question 32

Clostridium perfringens

Answer 32

Produces alpha-toxin (lecithinase) that can cause myonecrosis (gas gangrene) and hemolysis PERFringens PERForates a gangrenous leg

Question 33

Clostridium dificile

Answer 33

Produces a cytotoxin, an exotoxin that kills enterocytes, causing pseudomembranous colitis. Often 2' to ABX use, especially clindamycin or ampicillin. DI fficile causes DI arrhea Tx: metronidazole

Question 34

Anthrax

Answer 34

Caused by Bacillus anthracis: Gram (+), spore-forming rod that produces anthrax toxin. Only bacterium w/ a protein capsule (contains D-glutamate)

Question 35

Anthrax infxn via contact

Answer 35

Malignant pustules (painless ulcer) Can progress to bacteremia and death Black skin lesions - vesicular papules covered by black eschar \*[I think these only occur via contact route of infxn]

Question 36

Anthrax via inhalation of spores

Answer 36

Flulike Sx that rapidly progress to fever, pulmonary hemorrhage, mediastinitis, and shock

Question 37

Woolsorter's dz

Answer 37

Anthrax caused by inhalation of spores from contaminated wool

Question 38

Listeria monocytogenes route of transmission

Answer 38

Acquired by ingestion of unpasteurized milk/cheese and deli meats, or by vaginal transmission during birth.

Question 39

Listeria monocytogenes motility

Answer 39

Form actin rockets by which they move from cell to cell. Characteristic tumbling motility.

Question 40

Listeria monocytogenes Diseases

Answer 40

Can cause: amnionitis septicemia spontaneous abortion granulomatosis infantiseptica neonatal meningitis meningitis in the immunocompromised mild gastroenteritis (healthy individuals) \*Note: is the only G(+) organism w/ endotoxin\*

Question 41

Actinomyces and Nocardia

Answer 41

Both are G(+) rods forming long branching filaments, resembling fungi SNAP: S ulfa for N ocardia, A ctinomyces use P CN

Question 42

Actinomyces israelii

Answer 42

G(+) anaerobe Causes oral/facial abscesses that may drain thru sinus tracts in skin. Forms yellow sulfur granules in sinus tracts. Normal oral flora.

Question 43

Nocardia asteroides

Answer 43

G(+) and also weakly acid-fast aerobe found in soil. Causes pulmonary infxn in immunocompromised pts.

Question 44

Primary TB

Answer 44

Mycobacterium infects nonimmune host (usu. child). 1' TB causes hilar nodes and Ghon focus (usu. in lower lobes) -\> together = Ghon Complex Several outcomes: Heals by fibrosis Progressive lung dz Severe bacteremia Preallergic lymphatic or hematogenous dissemination

Question 45

Primary TB (Heals by fibrosis)

Answer 45

Immunity and hypersensitivity | Tuberculin (+)

Question 46

Primary TB | Progressive Lung dz

Answer 46

(Seen in HIV, malnutrition) | Death (rare)

Question 47

Primary TB (severe bacteremia)

Answer 47

| Miliary TB | Death

Question 48

Primary TB Preallergic lymphatic or hematogenous dissemination

Answer 48

| Dormant tubercle bacilli in several organs | Reactivation in adult life | Extrapulmonary TB or Reactivation of TB in lungs

Question 49

Extrapulmonary TB

Answer 49

CNS (parenchymal tuberculoma or meningitis) Vertebral body (Pott's dz) Lymphadenitis Renal GI

Question 50

Secondary TB

Answer 50

Due to re-infxn of partially immune hypersensitized host (usu. adult) or reactivation of dormant TB in the lungs Causes Fibrocaseous cavitary lesion (usu. in upper lobes) 

Question 51

PPD test and TB

Answer 51

PPD (+) w/ current infxn, past exposure, or BCG vaccinated PPD (-) if no infxn or anergic (steroids, malnutrition, immunocompromise, sarcoidosis)

Question 52

Ghon complex

Answer 52

TB granulomas (Ghon focus) w/ lobar and perihilar lymph node involvement. Reflects primary infxn or exposure.

Question 53

Mycobacterium tuberculosis

Answer 53

Causes TB (Sx: fever, night sweats, weight loss, and hemoptysis) Often resistant to multiple drugs ![]() ![]() ![]()

Question 54

Mycobacterium kansasii

Answer 54

pulmonary TB-like Sx

Question 55

Mycobacterium avium-intracellulare

Answer 55

Often resistant to multiple drugs Causes disseminated dz in AIDS

Question 56

Leprosy (Hansen's dz)

Answer 56

Caused by Mycobacterium leprae, an acid-fast bacillus that likes cool temperatures (thus infects skin and superficial nerves), and cannot be grown in vitro. See common Sx below:

Question 57

Reservoir for leprosy in the USA

Answer 57

armadillos

Question 58

Tx for Leprosy

Answer 58

long-term oral dapsone Toxicity is hemolysis and methemoglobinemia Alternative Tx's: Rifampin Combination of clofazimine and dapsone

Question 59

2 Forms of Hansen's dz

Answer 59

Lepromatous: and Tuberculoid Lepromatous is worse (failed cell-mediated immunity); tuberculoid is self-limited LEpromatous is LEthal

Question 60

Classifying G(-) Cocci

Answer 60

Maltose fermenter: Neisseria meningitidis Maltose non-fermenter: Neisseria gonorrhoeae

Question 61

G(-) Coccoid rods

Answer 61

Haemophilus influenzae Pasteurella - (animal bites) Brucella - (brucellosis) Bordetella pertusis

Question 62

G(-) Rods | Lactose fermenters | ?

Answer 62

Fast fermenters: Klebsiella E. coli Enterobacter Slow fermenters : Citrobacter Serratia (others)

Question 63

G(-) Rods | Lactose non-fermenters | ?

Answer 63

Oxidase (-): Shigella Salmonella Proteus Oxidase (+): Pseudomonas

Question 64

Lactose-fermenting enteric bacteria

Answer 64

Grow pink colonies on MacConkey's agar. Examples: C itrobacter, K lebsiella, E . coli, E nterobacter, S erratia (Lactose is KEE, so test w/ MacC onKEE'S agar

Question 65

PCN and Gram(-) bugs

Answer 65

G(-) bugs are resistant to benzylpenicillin G but may be susceptible to PCN derivatives such as ampicillin. The G(-) outer membrane inhibits entry of PCN-G and Vancomycin

Question 66

Neisseria (generally)

Answer 66

Both are: Gram(-) cocci Ferment glucose and produce IgA proteases. ![]()

Question 67

Neisseria gonorrheae (Gonococci)

Answer 67

No polysaccharide capsule No maltose fermentation (Gonococci ferment Glucose) No vaccine Sexually transmitted Causes gonorrhea, septic arthritis, neonatal conjunctivitis, PID

Question 68

Neisseria meningitidis (Meningococci)

Answer 68

Polysaccharide capsule Maltose fermentation (MeninGococci ferments Maltose and Glucose) Vaccine available Transmitted by respiratory and oral secretions Causes meningococcemia and meningitis, Waterhouse-Friderichsen syndrome

Question 69

Haemophilus influenzae Causes...? Produces what? Mode of transmission?

Answer 69

HaEMOP hilus causes: Epiglottitis, Meningitis, Otitis media, and Pneumonia. (Most invasive dz caused by capsular type B) Does NOT cause flu (influenza virus does) Produces IgA Protease Aerosol transmission

Question 70

Tx for Haemophilus influenzae

Answer 70

Ceftriaxone. Rifampin prophylaxis in close contacts.

Question 71

Culturing H. influenzae

Answer 71

Chocalate agar w/ factors V (NAD) and X (hematin) When a child has 'flu'\*, mom goes to the five (V ) and dime (X ) store to buy some chocolate [\*remember that H. influenzae does not cause flu]

Question 72

Haemophilus influenzae vaccine

Answer 72

Contains type B capsular polysaccharide conjugated to diphtheria toxoid or other protein to improve immune system recognition of polysaccharide and promote class switching. Given btw 2 and 18 months of age.

Question 73

Legionella pneumophila

Answer 73

Gram (-) rod Gram stains poorly --\> silver stain Grow on charcoal yeast extract culture w/ iron and cysteine. Think of a French legionnaire (soldier) with his silver helmet, sitting around a campfire (charcoal ) w/ his iron dagger -- he is no sissy (cysteine )

Question 74

Transmission of Legionella pneumophilia

Answer 74

Aerosol transmission from environmental water souce habitat. no person-to-person transmission.

Question 75

Dz's caused by Legionella pneumophila Tx?

Answer 75

Legionnaires' dz (severe pneumonia) Pontiac fever (mild influenza) Tx: erythromycin

Question 76

Pseudomonas aeruginosa Diseases?

Answer 76

Associated w/ wound and burn infxn PSEDUO Pneumonia (esp. in CF) Sepsis (black lesions on skin) Exteral otitis (swimmer's ear) UTI Drug use Diabetic Osteomyelitis (+ hot tub folliculitis) \*Think Pseudomonas in burn victims

Question 77

Pseudomonas aeruginosa classification and idenification

Answer 77

AERobic (AERuginosa) G(-) rod Non-lactose fermenting Oxidase (+) Produces pyocyanin (blue-green pigment) Has a grapelike odor Comes from water source

Question 78

Pseudomonas aeruginosa products

Answer 78

Endotoxin (fever, shock) Exotoxin A (inactivates EF-2)

Question 79

Pseudomonas aeruginosa Tx?

Answer 79

Aminoglycoside + extended-spectrum PCN (e.g., piperacillin, ticarcillin)

Question 80

Members of Enterobacteriacea

Answer 80

Diverse family including: E. coli Salmonella Shigella Klebsiella Enterobacter Serratia Proteus

Question 81

Commonalities among Enterobacteriaceae

Answer 81

All species have somatic (O) Ag (which is the polysaccharide of endotoxin). The capsular (K) Ag is related to the virulence of the bug. The flagellar (H) Ag is found in motile species. All ferment glucose and are oxidase (-) COFFEe Capsular (K) O Ag Flagellar Ag (H) Ferment glucose Enterobacteriaceae

Question 82

Klebsiella causes...

Answer 82

Pneumonia in alcoholics and diabetics (red currant jelly sputum) Also a cause of nosocomial UTIs relates to the 4 A's: Aspiration pneumonia Abscess in lungs Alcoholics di-A-betics

Question 83

Salmonella typhi

Answer 83

Causes typhoid fever: diarrhea, HA, rose spots on abdomen. Can remain in gallbladder chronically.

Question 84

Salmonella vs. Shigella

Answer 84

Both: Lactose non-fermenters Invade the intestinal mucosa and can cause bloody diarrhea Only Salmonella: Has flagella, and can spread hematogenously (like how Salmon swim), Produces H2S. Shigella: Do not have flagella, but can propel themselves while inside cells by actin polymerization Spread by 4 F's: Food, Fingers, Feces, and Flies Is more virulent (10 organisms infective vs. Salmonella: 100,000)

Question 85

Salmonellosis

Answer 85

Sx may be prolonged w/ ABX treatments There is typically a monocytic response

Question 86

Yersinia enterocolitica

Answer 86

Usually transmitted from pet feses (e.g., puppies), contaminated milk, or pork. Outbreaks are common in day-care centers. Sx can mimic Crohn's or appendicitis.

Question 87

Helicobacter pylori Causes...? Is a risk factor for...?

Answer 87

Causes: Gastritis and up to 90% of duodenal ulcers Risk factor for: peptic ulcer, gastric adenocarcinoma, and lymphoma

Question 88

Helicobacter pylori Classification/identification

Answer 88

G(-) Rod. Urease (+) --\> creates alkaline environment.

Question 89

Helicobacter pylori Tx?

Answer 89

Triple-therapy (two regimens): 1.) Bismuth (Pepto-bismol), metronidazole, and either TCN or amoxicillin 2.) Metronidale, omeprazole, and clarithromycin (\*more costly option)

Question 90

Spirochetes

Answer 90

Spiral-shaped w/ axial filaments. Include: Borellia (big size) Leptospira Treponema (BLT. B is Big) Only Borrelia can be vizualized w/ aniline dyes (Wright's or Giemsa). Treponema is vizualized w/ dark-field microscopy.

Question 91

Leptospira interrogans

Answer 91

Question mark-shaped bacteria found in water contaminated w/ animal urine.  Causes: Leptospirosis - (flu-like Sx, fever, HA, abdominal pain, jaundice. Most prevalent in tropics) Weil's dz (ictohemorrhagic leptospirosis) - severe form w/ jaundice and azotemia from liver and kidney dysfxn; fever, hemorrhage, and anemia

Question 92

Treponemal diseases

Answer 92

Treponemes are spirochetes. Treponema pallidum: Causes syphilis Treponema pertenue: Causes yaws; Infxn of skin, bone, and joints --\> healing w/ keloids --\> severe limb deformities Dz of the tropics. Not an STD, but VDRL positive.

Question 93

Syphilis Cause? Tx?

Answer 93

Caused by Treponema pallidum Tx w/ PCN G

Question 94

Primary syphilis

Answer 94

Presents w/ painless chancre (localized dz) Many treponemes present in chancre.

Question 95

Secondary syphilis

Answer 95

Disseminated dz w/ constitutional Sx's, macupapular rash (palms and soles), condylomata lata. Many terponemes are present in condylomata lata. S econdary Sy philis = Sy stemic

Question 96

Tertiary syphilis

Answer 96

gummas (chronic granulomas), arotitis (vasa vasorum destruction), neurosyphilis (tabes dorsalis), Argyll Robertson pupil (small pupils that accomodate but do not constrict/react [according to wikipedia, known as prostitutes pupils b/c they accomodate, but don't react - not sure what that means) Signs: Broad-based axilla Positive Romberg Charcot joints Stroke w/o HTN

Question 97

Congenital syphilis

Answer 97

CN VIII deafness Saber shins (outward curve like a saber)   Saddle nose  Hutchinson's teeth (smaller and more widely spaced) 

Question 98

Argyll Robertson Pupil

Answer 98

Constricts w/ accomodation but is not reactive to light. Associated w/ tertiary syphilus. Prostitute's Pupil - accomodates but does not react (???)

Question 99

VDRL vs. FTA-ABS

Answer 99

FTA-ABS is specfifc for treponemes, turns (+) earlies in dz, and remains (+) longest. VDRL and FTA-ABS: (+) result means active infxn (+) VDRL: Probably a false positive (+) FTA: Successfully treated FTA-ABS = Find The Ab ABSolutely: 1.) Most specific 2.) Earliest (+) 3.) Remains (+) longest

Question 100

VDRL False Positives

Answer 100

VDRL detects nonspecifc Ab that reacts w/ beef cardiolipin. Used for Dx of syphilis, but many biologic false positivies. Sources of false positives --\> VDRL V iruses (mono, hepatitis) D rugs R heumatic fever L upus and L eprosy

Question 101

List of zoonotic bacteria

Answer 101

Big Bad Bugs From Your Pet named Ella B artonella henselae B orrelia burgdorferi B rucella spp. F rancisella tularensis Y ersinia pestis P asteurella multocida

Question 102

Bartonella henselae Disease? Transmission?

Answer 102

Causes: cat scratch fever Transmission: cat scratch

Question 103

Borrelia burgdorferi Disease? Transmission?

Answer 103

Causes: Lyme disease transmission: Tick bite; Ixodes ticks that live on deer and mice

Question 104

Brucella spp. Disease? Transmission?

Answer 104

Causes: Brucellosis / undulant fever Transmission: Dairy products, contact w/ animals Un pasteurized dairy gives you Un dulant fever.

Question 105

Francisella tularensis Disease? Transmission?

Answer 105

Causes: Tularemia Transmission: Tick bite; rabbits, deer

Question 106

Yersinina pestis Causes? Transmission?

Answer 106

Causes: Plague Transmission: Flea bite; rodents (esp. prairie dogs)

Question 107

Pasteurella multocida Disease? Transmission?

Answer 107

Causes: Cellulitis Transmission: Animal bit; cats, dogs

Question 108

Gardnerella vaginalis Microscopic appearance? Causes ....? Tx?

Answer 108

Pleomorphic, gram-variable rod. Causes vaginosis (off-white/gray vaginal discharge w/ fishy smell; nonpainful) Mobiluncus (an anaerobe) is also involved. Vaginosis is associated w/ sexual activity, but is not an STD. Bacterial vaginosis is characterized by overgrowth of certain bacteria in vagina. Clue cells seen. Tx for vaginosis: metronidazole

Question 109

Clue cells

Answer 109

Seen in bacterial vaginosis Vaginal epithelial cells covered w/ bacteria 

Question 110

Rickettsiae Metabolism? Disease? Tx?

Answer 110

Obligate intracellular organisms Need CoA and NAD All except Coxiella are transmitted by an arthropod vector and cause HA, fever, and rash. Coxiella is an atypical rickettsia b/c it is transmitted by aerosol and causes pneumonia. Tx for most rickettsial infxns: TCN

Question 111

Classic triad for rickettsial infxns

Answer 111

HA, fever, rash (vasculitis)

Question 112

Rickettsia rickettsii Disease? Transmission? Tx?

Answer 112

Causes Rocky Mountain spotted fever Transmission via tick Tx: TCN

Question 113

Ricketsia typhus dz? transmission? Tx?

Answer 113

Causes endemic typhus Transmission via fleas Tx: TCN

Question 114

Rickettsia prowazekii Dz? Transmission? Tx?

Answer 114

Causes epidemic typhus Transmission via human body louse Tx: TCN

Question 115

Ehrlichia Dz? Transmission? Tx?

Answer 115

Causes Ehrlichiosis Transmission via tick Tx: TCN

Question 116

Coxiella burnetti Dz? Transmission? Tx?

Answer 116

Causes Q fever Q fever is Queer b/c it has no rash, no vector, and has negative Weil-felix, its causative roganism can survive outside for a long time, and does not have Rickettsia as its genus name. Transmission via inhaled aerosols Tx: TCN

Question 117

Rickettsial rash vs. Typhus rash

Answer 117

Rickettsial rash starts on hands and feet; Typhus rash starts centrally and spreads out: R ickettisa on the wR ists, T yphus on the T runk.

Question 118

Rocky Mountain Spotted Fever

Answer 118

Caused by Rickettsia rickettsii Sx: rash on palms and soles (migrating to wrists, ankles, then trunk), HA, fever. Endemic to East Coast (in spite of its name).

Question 119

Palm and sole rash

Answer 119

Seen in: C oxsackievirus A infxn (hand, foot, and mouth dz) R ocky Mountain spotted fever S yphilis (You drive CARS using your palms and soles)

Question 120

Weil-Felix Reaction

Answer 120

Assays for anti-rickettsial Abs, which cross-react w/ Proteus Ag. Weil-Felix is usually positive for typhus and Rocky Mountain spotted fever, but negative for Q fever.

Question 121

Chlamydiae

Answer 121

Cannot make their own ATP --\> obligate intracellular organisms Cause mucosal infxns Chlamydial cell wall is unusual in that it lacks muramic acid Cell cycle w/ 2 forms: elementary body and initial/reticulate body

Question 122

Lab Dx, Tx for Chlamydiae infxns

Answer 122

Dx: cytoplasmic inclusions seen on Giemsa or fluorescent Ab-stained smear Tx: erythromycin or TCN

Question 123

Chlamydiae: Elementary body

Answer 123

Small, dense. E lementery E nters cells via endocytosis. 

Question 124

Chlamydiae: Initial or Reticulate body

Answer 124

R eticulate body R eplicates in cell by fission 

Question 125

Chlamydia trachomatis Causes...? Tx?

Answer 125

Causes: reactive arthritis conjunctivitisd nongonococcal urethritis pelic inflammatory dz (PID) As with all Clamydiae, Tx w/ erythromycin or TCN

Question 126

Chlamydia pneumoniae Disease? Transmission?

Answer 126

Causes atypical pneumonia Transmitted by aerosol As w/ all Chlamydiae, Tx w/ erythromycin or TCN

Question 127

Chlamydia psittaci Disease? Transmission?

Answer 127

Causes atypical pneumonia Transmission by aerosol \*notable for avian reservoir As w/ all Chlamydiae, Tx w/ erythromycin or TCN

Question 128

Chlamydia trachomatis serotypes A, B, and C

Answer 128

Chronic infxn, cause blindness in Africa (ABC = Africa / Blindness / Chronic Infxn)

Question 129

Chlamydia trachomatis types D-K

Answer 129

Urethritis/PID Ectopic pregnancy Neonatal pneumonia Neonatal conjunctivitis\* Neonatal dz can be acquired during passage thru infected birth canal Tx: oral erythromycin

Question 130

Chlamydia trachomatis serotypes L1, L2, and L3

Answer 130

Lymphogranuloma venerum (Acute lymphadenitis - positive Frei test) L 1-3 = L ymphogranuloma venerum

Question 131

Mycoplasma pneumoniae Causes...? Epidemiology of dz?

Answer 131

Classic cause of atypical walking pneumonia (insidious onset, HA, nonproductive cough, diffuse interstitial infiltrate) Mycoplasmal pneumonia is more common in pts \< 30 years of age. Frequent outbreaks in military recruits and prisons.

Question 132

Mycoplasma pneumoniae Info on bacterium?

Answer 132

 No cell wall. Not seen on gram stain. Only bacterial membrane containing cholesterol. Grown on Eaton's agar.

Question 133

Mycoplasmal pneumonia Dx and labs? Tx?

Answer 133

X-ray looks worse than pt (walking pneumonia w/ diffuse interstitial infiltrate) High titer cold agglutinins (IgM) Tx: TCN or erythromycin (bugs are naturally PCN-resistant b/c they have no cell wall)