Line probe assay (LPA — Hain GenoType MTBDRplus) detects resistance to rifampicin by identifying mutations in which gene?
- A katG and inhA promoter
- B embB codon 306
- C rpoB (81-bp hotspot region) ✓
- D gyrA and gyrB
Correct answer: C. rpoB (81-bp hotspot region)
Explanation
Rifampicin resistance in M. tuberculosis results from mutations in the 81-bp core region of rpoB (encoding the beta-subunit of RNA polymerase), which accounts for >95% of RIF-resistant strains. LPA detects these mutations using reverse hybridisation of wild-type and mutant probes. Mutations in katG and inhA promoter confer isoniazid resistance. embB mutations confer ethambutol resistance, and gyrA/gyrB mutations confer fluoroquinolone resistance.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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