Which drug is an example of non-beta-lactam PG inhibitors used against Mycobacterium tuberculosis?

Which drug is an example of non-beta-lactam PG inhibitors used against Mycobacterium tuberculosis?

• A. Vancomycin
• B. Clavulanic acid
• C. Isoniazid
• D. Bacitracin

Answer: (C)

The key idea is how TB drugs disrupt the mycobacterial cell wall without using beta-lactams. Isoniazid fits this because it is a non-beta-lactam that specifically targets Mycobacterium tuberculosis by blocking the synthesis of mycolic acids, essential long-chain fatty components of the mycobacterial cell wall. Once activated inside the bacterium, isoniazid inhibits enzymes involved in mycolic acid production, weakening the cell wall and killing or inhibiting the bacteria. This mechanism is distinct from beta-lactams, which interfere with peptidoglycan cross-linking, and it explains why isoniazid is a cornerstone TB drug. The other options don’t align with this TB-specific, non-beta-lactam cell-wall strategy. Vancomycin and bacitracin are non-beta-lactam inhibitors of peptidoglycan synthesis, but they are not effective or routinely used against tuberculosis because of poor penetration into the waxy mycobacterial cell envelope and limited activity against Mycobacterium tuberculosis. Clavulanic acid is a beta-lactamase inhibitor, not an antimicrobial by itself. So isoniazid is the best choice for a non-beta-lactam agent used against TB.

The key idea is how TB drugs disrupt the mycobacterial cell wall without using beta-lactams. Isoniazid fits this because it is a non-beta-lactam that specifically targets Mycobacterium tuberculosis by blocking the synthesis of mycolic acids, essential long-chain fatty components of the mycobacterial cell wall. Once activated inside the bacterium, isoniazid inhibits enzymes involved in mycolic acid production, weakening the cell wall and killing or inhibiting the bacteria. This mechanism is distinct from beta-lactams, which interfere with peptidoglycan cross-linking, and it explains why isoniazid is a cornerstone TB drug.

The other options don’t align with this TB-specific, non-beta-lactam cell-wall strategy. Vancomycin and bacitracin are non-beta-lactam inhibitors of peptidoglycan synthesis, but they are not effective or routinely used against tuberculosis because of poor penetration into the waxy mycobacterial cell envelope and limited activity against Mycobacterium tuberculosis. Clavulanic acid is a beta-lactamase inhibitor, not an antimicrobial by itself. So isoniazid is the best choice for a non-beta-lactam agent used against TB.