Line probe assay (GenoType MTBDRsl) is used to detect second-line drug resistance in MTB. This assay detects mutations conferring resistance to fluoroquinolones and second-line injectables. Which gene mutations are detected for fluoroquinolone resistance?
- A rrs and eis mutations — encoding 16S rRNA and aminoglycoside acetyltransferase
- B katG and inhA mutations — encoding catalase-peroxidase and enoyl-ACP reductase
- C gyrA and gyrB mutations — encoding DNA gyrase subunits targeted by fluoroquinolones ✓
- D rpoB and rpoC mutations — encoding RNA polymerase beta and beta' subunits
Explanation
GenoType MTBDRsl v2.0 (Hain Lifescience) simultaneously detects resistance-associated mutations for: fluoroquinolones (FQ) — mutations in gyrA codon 90, 91, 94 and gyrB codons 461, 499 (DNA gyrase subunits are the FQ target in MTB); and second-line injectable drugs (amikacin, capreomycin, kanamycin) — mutations in rrs (16S rRNA gene) at positions A1401G, C1402T, G1484T, and in eis (enhanced intracellular survival) promoter region. MTBDRplus v2.0 detects first-line resistance: rpoB (rifampicin), katG and inhA (isoniazid). LPA results are available in 4–6 hours from AFB smear-positive specimens, making it a rapid tool for pre-XDR/XDR-TB detection.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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