Drug resistance among different genotypes of Mycobacterium tuberculosis isolated from patients from Tiruvallur, south India .

Sivakumar, S.; Selvakumar, N.; Narayanan, S.

Infection, Genetics and Evolution; 2011; 11; 980-986.     

Abstract: India continues to have the highest tuberculosis incidente, accounting for one fifth of the global incidente and 2/3rd of the cases in South East Asia . The TB burden is also augmented by multi drug resistance and HIV. Although inadequate and inappropriate treatment is responsable for drug resistance, pathogen's genetic background may also play a role. The aim of this study was to understand the distribution of different genotypes of Mycobacteriuym tuberculosis in the Tiruvallur, rural area in south India and its association with drug resistance. A total of 1649 M. tuberculosis isolates were genotyped by IS6110 RFLP and spoligotyping. Drug susceptibility testing was done by minimum inhibitory concentration method (MIC) on all the samples. As reported earlier, the isolates with single and low copy IS6110 accounted for 66% hmong the 1649 M. tuberculosis strains genotyped. The majority (84%) of our strains belonged to the East African Indian (EAI) lineage, 28.6% to EA13 sublineage and 19.5% to EA15 sublineage. Rifampicin and streptomycin mono resistance followed by MDR (Multi-Drug Resistance, resistance to at least rifampicin and isoniazid) [(OR 0.2 [95% CI 0.11-0.46)], P<0.05)] were more common between Central Asian (CAS), T and Beijing compared to EAI lineage. In spite of the predominante of EAI lineage, its association with drug resistance was lower compared to the other genotypes prevalent in Trivallur, south India . .

Keywords: Mycobacterium tuberculosis (M. tb); East African Indian genotype; Drug resistance

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