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

C1q

Answer

C3b

Answer

C4b2a

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

Inhibits ribosomal 30S subunit

Answer

Disrupts the cell membrane directly

Answer

Inhibits DNA gyrase

Question 3

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

Accepted Answer

Hepatitis A

Answer

Hepatitis B

Answer

Hepatitis C

Answer

Hepatitis D

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

< 500 cells/µL

Answer

< 350 cells/µL

Answer

< 100 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

Inhibition of ergosterol synthesis (14α-demethylase)

Answer

Binding to ergosterol and disrupting membrane

Answer

Inhibition of thymidylate synthase

Question 6

Clostridium difficile causes antibiotic-associated colitis primarily through production of:

Accepted Answer

Exotoxins A and B

Answer

Endotoxin (lipopolysaccharide)

Answer

Protein A

Answer

Leukotoxin