Micro

Question 1

What is the causative organism of lymphogranuloma venereum?

Answer 1

Chlamydia trachomatis

Question 2

How does a chancroid present?

Answer 2

Erythematous papule that rapidly turns into a pustule, and then a painful ulcer. The ulcer is 1-2 cm with a dermarcated boarder and is covered in a gray/yellow purulent exudate

Question 3

What causes a chancroid ulcer?

Answer 3

Haemophilus ducreyi

Question 4

What region do you find histoplasmosis in?

Answer 4

Central US; most frequently Ohio, Mississippi, Missouri river valleys

Question 5

How does Coccidioides appear microscopically?

Answer 5

20-60 micrometer nonbudding spherules filled with endospores

Question 6

Molluscum contagiosum is part of what virus family?

Answer 6

Poxvirus

Question 7

What is the genome of the pox virus?

Answer 7

DsDNA, linear, enveloped and replicates in the cytoplasm with a DNA dependent RNA polymerase

Question 8

An extracellular atypical fungus infecting patients with HIV?

Answer 8

Pneumocystis jirovecii

Question 9

What do the granulomas look like of a person infected with Bartonella henelae?

Answer 9

Stellate granulomas with central necrosis and the organism

Question 10

What causes cysticercosis?

Answer 10

Taenia solium

Question 11

How does S aureus inhibit opsonization?

Answer 11

Protein A - binds Fc component of IgG

Question 12

Skin scrapings from someone infected with HSV demonstrates what?

Answer 12

Intranuclear inclusion bodies

Question 13

What family does RSV belong to?

Answer 13

Paramyxoviridae

Question 14

How does one become infected with toxoplasma gondii?

Answer 14

Ingest the oocysts from cat feces or incompletely cooked lamb or pork

Question 15

What does hantavirus cause? What is its mode of transmission?

Answer 15

Fatal respiratory illness; endemic to desert of SW US. Rodent droppings

Question 16

Patient comes in contact with infected bird droppings and contracts and atypical pneumonia. What is the likely organism?

Answer 16

Chlamydophila psittaci

Question 17

What does Rickettsia prowazekii cause?

Answer 17

Epidemic louse borne typhus

Question 18

What do Cowdry type A inclusions look like?

Answer 18

Eosinophilic intranuclear viral inclusions

Question 19

What is the classic triad of gestational toxoplasmosis?

Answer 19

Chorioretinitis, intracranial calcifications, encephalitis leading to hydrocephalus

Question 20

What is the mechanism of cholera toxin?

Answer 20

Activating AC by ADP ribosylation of a GTP binding protein

Question 21

What is the mechanism of exotoxin A? What organism produces it?

Answer 21

Pseudomonas aeruginosa; inhibits EF2 by ADP ribosylation

Question 22

What kind of media do V vulnificus and parahaemolyticus grow on?

Answer 22

Alkaline media - TCBS

Question 23

CMV is part of what virus family?

Answer 23

Herpesvirus family

Question 24

What is erythema infectiosum?

Answer 24

Parvovirus B19 - slapped cheek fever

Question 25

What is the mechanism causation of diarrhea due to cryptosporidiosis?

Answer 25

C parvum infects the brush border and causes direct lysis of the cells

Question 26

Fungal infection that shows multiple tiny oval forms within macrophages on biopsy?

Answer 26

Histoplasmosis

Question 27

During what stage of the bacterial life cycle do spores form?

Answer 27

Stationary phase - when cell growth ceases because of depletion of nutrients or accumulation of toxins

Question 28

What is ecthyma grangrenosum? What causes it?

Answer 28

Black, necrotic center and a riased hemorrhagic ring outside; due to infection with P aeruginosa

Question 29

What are common causes of septic abortion?

Answer 29

S aureus (very common), others: gram neg bacilli (E coli) and GBS

Question 30

What generation is cefotaxime in?

Answer 30

3rg gen

Question 31

Do third generation cephalosporins cover listeria?

Answer 31

No

Question 32

Patient who recently underwent a genitourinary procedure has a UTI two days later. Gram stain shows gram + cocci in pairs and chains. Additionally, the organism is unable to convert nitrates to nitrites. What is the probable organism?

Answer 32

Enterococci - gamma hemolysis, PYR +, ability to grow in bile and 6.5% NaCl

Question 33

How does RSV present?

Answer 33

Age <2 with antecedent nasal congestion/discharge and cough, following by wheezing/crackles and resp distress