Drug resistance profiles of Mycobacterium tuberculosis isolates to first line anti-tuberculous drugs: A five years study

Background: Drug resistance is a major problem in the treatment of tuberculosis (TB). An estimate of drug resistance is extremely important in the epidemiology and control of TB. However, an assessment of the magnitude of drug resistance in TB is not very well described globally and data remains scantier for India. In view of this, we reviewed our data over last five years. Materials and Methods: Six hundred and seventy-three Mycobacterium tuberculosis isolates were subjected to drug susceptibility against primary anti-tuberculosis drugs by economic variant proportion method. All isolates resistant to isoniazid and rifampicin were taken as multi-drug resistant (MDR). Results: Out of the 673 strains tested, 95 (14.11%) showed monoresistance, 365 (54.23%) strains were found to be resistant to more than one drug. A total of 118 (17.53%) strains were found to be resistant to all the four drugs tested. MDR was seen with 320 (47.54%) isolates. This study observed maximum resistance with rifampicin (74.4%) followed by streptomycin (70.0%), isoniazid (53.2%), and ethambutol (21.7%). Conclusion: While this information may not reflect true prevalence of drug resistance in the region, this may help in further planning long term surveillance studies to know the trend of drug resistance in this area.