Molecular Genetic Determination of MDR–TB Isolates from West Bengal, India

Tuberculosis (TB) is one of the leading causes of death from an infectious disease worldwide. India remains to be the country carrying highest burden of the disease. One of the potent problems of present days, in this field, is the emergence of Multi-Drug-Resistant Tuberculosis (MDR-TB). MDR is defined as resistance to isoniazid (INH) and rifampin (RIF). The spread of MDR-TB is one of the biggest challenges to global public health system. Thus, detection of MDR-TB strains is critically important for containment of global TB epidemics. In this study, we are determining the MDR incidence rate in the West Bengal state of India, which is one of the most TB prone areas of the world. The RIF-resistant mutations of Mycobacterium tuberculosis (MTB) were shown to map in the rpoB locus and INH-resistant mutations of MTB were shown to map in inhA and katG loci. Therefore, in the present study, we have detected MDR-TB strains by mapping rpoB, katG & inhA mutations. Our Line Probe Assay (LPA) based results from a vast pool of MTB organisms (carrying 3653 bonafide sputum positive patient isolates) indicated the presence of 14.37% MDR isolates which matches in general with the previously reported results from various parts of the world (approx. 12-16%). Therefore, we conclude that our MDR rate is generally comparable to that of the other investigations performed in the rest of the world. We also found that the male patients are more likely to contract the MDR strains than the female patients (1.97:1.0). This data also conforms to the global statistics.