Microbiology MCAT Practice Question
A 42-year-old man with a 3-week history of productive cough, night sweats, and weight loss is diagnosed with pulmonary tuberculosis. Acid-fast bacilli are confirmed on sputum smear microscopy. Researchers are developing a novel antituberculous agent that selectively inhibits arabinosyl transferase, a critical enzyme in the biosynthesis of arabinogalactan, a major component of the mycobacterial cell wall. Which of the following best explains the antimicrobial mechanism of this proposed drug?
Answer choices
- ALoss of cell wall integrity leading to increased opsonization and enhanced phagocytosisCorrect answer
- BInhibition of mycolic acid cross-linking, preventing cell wall rigidity but preserving permeability barrier function
- CActivation of dormant mycobacterial genes that encode alternative cell wall polysaccharides
- DUpregulation of efflux transporter expression to eliminate intracellular drug accumulation
- EPrevention of lipoarabinomannan synthesis, reducing antigenic stimulation of macrophages
- FDisruption of peptidoglycan cross-bridges, analogous to beta-lactam antibiotic activity
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