Mycobacterium tuberculosis strain lineage in mixed tribal population across India and Andaman Nicobar Island.

Azger Dusthackeer,Anil Kumar Indira Krishnan,Harpreet Kaur,Pradeep Das,Avi Kumar Bansal,Vivek Kashyap,Sucharitha Kannappan Mohanvel,Anil Jacob Purthy,B Mahizhaveni,Tahziba Hussain,Rajesh Mondal,Ashok Kumar,S Azhagendran ,P Vijayachari ,D Raghunath ,Shri Vijay Bala Yogendra Shivakumar ,V G Rao ,Madhuchhanda Das ,Sharmilee Vetrivel ,S Raghavi ,Ramesh Singh Yadav ,Praveen Kumar Anand ,Kangjam Rekha Devi ,Beena Thomas

doi:10.1007/s11274-021-03164-6

Abstract

In India, the tribal population constitutes almost 8.6% of the nation's total population. Despite their large presence, there are only a few reports available on Mycobacterium tuberculosis (M. tb) strain prevalence in Indian tribal communities considering the mobile nature of this population and also the influence of the mainstream populations they coexist within many areas for their livelihood. This study attempts to provide critical information pertaining to the TB strain diversity, its public health implications, and distribution among the tribal population in eleven Indian states and Andaman & Nicobar (A&N) Island. The study employed a population-based molecular approach. Clinical isolates were received from 66 villages (10 states and Island) and these villages were selected by implying situation analysis. A total of 78 M. tb clinical isolates were received from 10 different states and A&N Island. Among these, 16 different strains were observed by spoligotyping technique. The major M. tb strains spoligotype belong to the Beijing, CAS1_DELHI, and EAI5 family of M. tb strains followed by EAI1_SOM, EAI6_BGD1, LAM3, LAM6, LAM9, T1, T2, U strains. Drug-susceptibility testing (DST) results showed almost 15.4% of clinical isolates found to be resistant to isoniazid (INH) or rifampicin (RMP) + INH. Predominant multidrug-resistant (MDR-TB) isolates seem to be Beijing strain. Beijing, CAS1_DELHI, EAI3_IND, and EAI5 were the principal strains infecting mixed tribal populations across India. Despite the small sample size, this study has demonstrated higher diversity among the TB strains with significant MDR-TB findings. Prevalence of Beijing MDR-TB strains in Central, Southern, Eastern India and A&N Island indicates the transmission of the TB strains.

Highlights

Indian tribal population is one of the highly neglected groups of people due to geographical and cultural barriers in terms of health and associated pubic health services (Govt of India 2020-21)
According to Gagneux et al (2007) M. tuberculosis can be classified into lineages 1 (L1) to lineage 7 (L7), wherein L5, L6 and L7 are the types prevalent in African countries. lineages 2 (East Asian) which includes the Beijing family of strains are associated with an increased probability of acquiring drug resistance than L3 and L4 while the least being L1 (Devi et al 2015; Blouin et al 2012; Firdessa et al 2013; Comas 2004 and Munsiff 2006)
L2 and L3 are omnipresent in all the reported states which implicates that the emergence of drug-resistant phenotypes in these tribal areas is more likely to occur requiring more stringent control measures focusing on the tribal population

Summary

Introduction

Indian tribal population is one of the highly neglected groups of people due to geographical and cultural barriers in terms of health and associated pubic health services (Govt of India 2020-21). Our research intended to identify the types of M. tuberculosis strains prevalent across several parts of India, A&N Island tribal groups which seem to report different strains and the associated clusters across India. It is the foremost intervention upon mixed tribal populations across India, A&N Island with limited sample size. Our study aimed to estimate the prevalence of M. tuberculosis lineages among mixed tribal groups in tribal areas of Central, Southern, Eastern India, and A&N Island

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Conclusion