Prevalence of multidrug resistant Mycobacterium tuberculosis in Lucknow, Uttar Pradesh.

BACKGROUND & OBJECTIVE: Multi-drug resistant (MDR) Mycobacterium tuberculosis isolates may be transmitted within communities due to dense population and poor hygienic conditions. For proper management and control of MDR-TB, understanding drug susceptibility pattern of M. tuberculosis isolates and their transmission pattern in every health care setting are essential. In the present study, we attempted to describe the current prevalence of MDR-TB in Lucknow district, Uttar Pradesh, and our observations on transmission of MDR isolates among populations in and around this area.

METHODS: Patients diagnosed as that of pulmonary tuberculosis (PTB) were enrolled from primary level (PLH), secondary level (SLH) and tertiary level (TLH) healthcare centres from Lucknow district. Detailed history of intake of antitubercular drug in the past was taken to decipher initial/ acquired drug resistance. Sputum samples were cultured on Lowenstein-Jensen media to isolate mycobacteria. Drug susceptibility patterns of isolated M. tuberculosis isolates were recorded using 1 per cent proportion method. Transmission of MDR isolates in community was accessed by random amplified polymorphic DNA (RAPD). Isolates showing same band pattern on RAPD were retyped using different primers targeted to the inverted repeat sequence of IS6110 copies in M. tuberculosis genome.

RESULTS: A total of 686 M. tuberculosis isolates were obtained from 1162 patients, of which 318 were from untreated subjects and 368 were from patients who were treated for tuberculosis in the past. Prevalence of MDR was 19.8 per cent, initial and acquired being 13.2 and 25.5 per cent respectively. Prevalence of resistance to any drug, MDR and individual drug resistance to isoniazid, streptomycin, ethambutol and rifampicin was significantly higher in patients who were treated in the past. Drug resistance was significantly higher at tertiary level health care compared to primary level health care. Genotypically similar clusters were seen at all levels of health care. It was not always possible to establish geographic connections within clusters.

INTERPRETATION & CONCLUSION: High prevalence of both initial and acquired MDR was noted in M. tuberculosis isolates collected from pulmonary tuberculosis patients. Presence of small clusters of MDR isolates at all health care levels suggests transmission within the studied community.