The Efficacy of Genotype? MTBDRplus Assay in Rapid Detection of Rifampicin and Isoniazid Resistance in Mycobacterium tuberculosis Complex Isolates

Aims To evaluate the efficacy of GenoType MTBDRplus assay in rapid detection of Tuberculosis cases resistant to Isoniazid and/or Rifampicin and to detect the drug resistant genes. Materials and Methods Early morning sputum samples from 100 clinically suspected TB patients were collected from south Gujarat region and subjected to sputum microscopy, culture, Drug Susceptibility Testing (DST). GenoType Mycobacterium Tuberculosis Drug Resistance (MTBDR) plus assay was done on the culture isolates to detect Rifampicin and/or Isoniazid resistance. The efficacy of the Genotype MTBDRplus assay was compared with that of the phenotypic drug susceptibility test-1 %Proportion method. Results Out of 100 patients, 27 were smear positive by Ziehl-Neelsen method and 30 were culture positive on Lowenstein Jensen medium. Out of 30 isolates, 7 isolates (23.3 %) showed drug resistance by conventional DST method while 8 isolates (26.67 %) showed drug resistance by the Genotype MTBDRplus. Out of 8 isolates, 3 isolates (37.5 %) showed drug resistance to only Isoniazid, 1 isolate (12.5 %) showed drug resistance to only Rifampicin and 4 isolates (50 %) were multi-drug resistant for Rifampicin and Isoniazid with molecular method-Genotype MTBDRplus. Conclusion The MTBDRplus assay allows the rapid detection of drug resistance patterns with significantly lesser turnaround time as compared to conventional DST method.