In drug-resistant tuberculosis, bedaquiline inhibits which target, making it effective against TB strains resistant to conventional first and second-line drugs?

• A InhA (enoyl-ACP reductase) in mycolic acid synthesis
• B RNA polymerase β subunit (rpoB)
• C ATP synthase (subunit c of mycobacterial F1F0 ATP synthase) ✓
• D 30S ribosomal subunit (aminoglycoside target)

Explanation

Bedaquiline (a diarylquinoline) selectively inhibits the mycobacterial F1F0 ATP synthase (specifically subunit c), disrupting ATP production and killing both replicating and dormant Mycobacterium tuberculosis. This unique mechanism of action means cross-resistance with conventional antitubercular drugs (isoniazid, rifampicin, fluoroquinolones) does not occur. InhA is the target of isoniazid and ethionamide; rpoB is targeted by rifampicin. Bedaquiline is used in MDR-TB BPaL regimens (bedaquiline, pretomanid, linezolid).

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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