FPGEE FPGEE Microbiology and Immunology 2

Question 1

Which component of the complement system forms the membrane attack complex (MAC)?

Accepted Answer

C5b-9

Answer

The membrane attack complex consists of complement proteins C5b, C6, C7, C8, and multiple C9 molecules that create pores in bacterial membranes.

Question 2

Vancomycin is the drug of choice for serious infections caused by MRSA because it:

Accepted Answer

Binds D-Ala-D-Ala of peptidoglycan precursors

Answer

Vancomycin binds to the D-Ala-D-Ala terminus of peptidoglycan precursors, preventing transglycosylation and cell wall synthesis without using PBPs.

Question 3

Which hepatitis virus is transmitted via the fecal-oral route and does NOT cause chronic infection?

Accepted Answer

Hepatitis A

Answer

Hepatitis A virus (HAV) is transmitted via contaminated food/water (fecal-oral) and causes only acute, self-limiting infection without chronicity.

Question 4

The CD4+ T helper cell count in an HIV-positive patient below which prophylaxis for Pneumocystis jirovecii pneumonia (PCP) is initiated is:

Accepted Answer

< 200 cells/µL

Answer

PCP prophylaxis with trimethoprim-sulfamethoxazole is initiated when the CD4+ count falls below 200 cells/µL.

Question 5

Which antifungal mechanism is unique to the echinocandin class (e.g., caspofungin)?

Accepted Answer

Inhibition of β-1,3-glucan synthase

Answer

Echinocandins inhibit β-1,3-glucan synthase, disrupting fungal cell wall synthesis, which has no human counterpart.

FPGEE Exam Practice Test