Study of drug resistance profile in Multidrug resistant tuberculosis (MDR TB) patients attending a tertiary care hospital at Mumbai

Abstract

Introduction: RNTCP estimates MDR in India as 2.5% in new & 16% in treated cases & reports success of MDR treatment in only 52%. Mumbai is a hot spot for TB drug resistance in India. A prior study revealed 29.4% MDR, 56.8% pre XDR, 10.6% XDR & 5.6% XXDR in the greater metropolitan area of Mumbai. Aims & objectives: To analyse the profile of drug resistance in MDR TB patients following up in a tertiary care hospital at Mumbai. Methods: A retrospective observational study enrolled 52 MDR TB patients diagnosed as per drug susceptibility testing (DST) on TB MGIT cultures. Patients were classified into 3 categories depending on DST results: MDR TB, pre XDR TB, XDR TB. Analysis of resistance to other drugs on DST panel was also done. Results: 50 (96%) of 52 MDR TB patients were resistant to at least 2, 29 (58%) were resistant to at least 3 & 20 (40%) were resistant to at least 4 other drugs currently recommended in the empirical treatment of MDR TB ( diagnosed on Xpert ) as per national guidelines. Of the 50 that were at least 2 drug resistant, 39 (78%) were resistant to at least E & Z. 29 (60%) were resistant to ethionamide. 100% sensitivity to clofazamine was seen. Of 52 MDR TB patients, 27 (51.92%) were Pre XDR (all quinolone) & 5 (9.6%) were XDR TB. Conclusion: This study observes a high resistance to at least 2 or more drugs & high prevelance of Pre XDR in MDR TB patients. This necessitates LPA to 1st and 2nd line drugs whilst awaiting DST & individualizing drug regimens to prevent high failure rates of empirical MDR regime as per national guidelines. In our view this will prevent further transmission of MDR TB & conversion to XDR TB.