Fluoroquinolone resistance in Mycobacterium tuberculosis is most commonly due to mutations in which gene?

• A rpoB
• B katG
• C inhA
• D gyrA ✓

Explanation

Fluoroquinolones inhibit DNA gyrase (topoisomerase II) in bacteria; gyrA encodes the A subunit of DNA gyrase, and mutations in the quinolone resistance-determining region (QRDR) of gyrA are the primary mechanism of fluoroquinolone resistance in M. tuberculosis. This is critical because fluoroquinolones (levofloxacin, moxifloxacin) are Group A drugs in MDR-TB regimens. rpoB mutations confer rifampicin resistance; katG and inhA mutations confer isoniazid resistance.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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