Genetic diversity and drug susceptibility profile of Mycobacterium tuberculosis isolated from different regions of India.

Objectives: Molecular genotyping profiles of Mycobacterium tuberculosis (MTB) provide a valuable insight into the evolution and transmission of the bacilli. Due to the lack of comprehensive national level data from India on this subject, we performed this study to determine the recent trends and distribution of various MTB lineages circulating in India.

Methods: A total of 628 MTB isolates were obtained from North, West, South, Central and Eastern India. Spoligotyping and drug susceptibility testing was performed by using manufacturer's instructions.

Results: Spoligotyping detected 102 distinct spoligo-patterns. A total of 536 (85.3%) isolates were distributed into 85 SITs which matched the pre-existing database, whereas 17 SITs were newly created for 34 (5.4%) isolates. Overall, CAS family genotype was predominant, comprising 222 (35.4%) isolates, followed by EAI in 152 (24.2%), Beijing in 108 (17.2%), Manu in 41 (6.5%), T in 30 (4.8%), H in 6 (0.9%), X in 3 (0.5%) and one (0.2%) each in Ural and AFRI. Drug susceptibility testing identified 134 (21.3%) isolates as multi drug resistant (MDR).

Conclusions: The CAS lineage had a pan India presence but EAI lineage was confined to southern parts of India. Beijing genotype of MTB was significantly associated (p-value <0.0001) with MDR.