en Epidemiologic studies including microbial genotyping, phenotyping and serotyping Epidemiologic studies including microbial genotyping, phenotyping and serotyping Original article Original article <span style="font-size:11pt"><span style="line-height:normal"><span sans-serif="" style="font-family:Calibri,"><b><span lang="EN-IN" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">Introduction</span></span></b><span lang="EN-IN" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">: Understanding the epidemiological and clinical characteristics of different tuberculosis strains is crucial for developing improved diagnostic tools, drugs, and vaccines for tuberculosis management</span></span><span lang="EN-GB" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">. This study aimed to investigate the molecular epidemiology of <i>Mycobacterium tuberculosis</i> using spoligotyping, a widely used molecular typing method, to understand the genetic diversity and transmission dynamics of <i>M. tuberculosis</i>, on isolates obtained from patients with pulmonary tuberculosis in central Kerala</span></span><span lang="EN-IN" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">. <b>Methods</b>: In a prospective study at a tertiary care hospital, 404 respiratory specimens from patients with symptoms suggestive of TB were collected. Specimens underwent Ziehl-Neelsen staining, culture in liquid (BD BACTEC&trade; MGIT&trade;) and solid (Lowenstein-Jensen) media, and standard drug susceptibility testing with the MGIT system. Molecular analysis involved conventional PCR amplification of genomic DNA to generate sufficient genetic material for analysis, using species-specific and primers targeting the direct repeat region, followed by spoligotyping to assess the genetic diversity of the <i>M. tuberculosis</i> strains. <b>Results:</b> </span></span><span lang="EN-IN" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">Out of 404 samples from individuals with suspected pulmonary TB, Mycobacteria were cultured from 48 [11.9%] of the samples. Amongst the 48 culture-positive <i>M. tuberculosis</i> isolates, 20 (41.66%) were sensitive to all five first-line anti-TB drugs, and 3 (6.2</span></span><span lang="EN-IN" style="font-size:10.0pt">%</span><span lang="EN-IN" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">) were resistant to all five drugs. Spoligotyping of the 47 isolates showed that 36.1% [n=17] of the isolates belonged to the <i>M. tuberculosis</i> EAI3 (East African-Indian) family, followed by 27.6% (n=13) <i>M. tuberculosis</i> EAI5 and 21.2% (n=10) <i>M. tuberculosis</i> CAS (Central Asia). Other families observed in this study, although less prevalent, were <i>M. tuberculosis</i> Beijing, 8.5% (n=4), family 33, 4.3% (n=2), and Mycobacterium bovis-BCG family, 2.1% (n=1)</span></span><span lang="EN-IN" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">. <b>Conclusion:</b> This study explored the genetic diversity and distribution of circulating <i>M. tuberculosis</i> strains in central Kerala. Genotyping <i>M. tuberculosis</i> strains provides valuable insights into TB transmission and progression, which can inform the development of effective public health control strategies.</span></span></span></span></span> Genetic diversity, Mycobacterium tuberculosis complex, Drug susceptibility Spoligotyping 42 49 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-439-4&slc_lang=en&sid=1 Sreeja Nair sreeja7805@gmail.com 0000-0002-1989-9541 Yes Department of Microbiology, Pushpagiri Institute of Medical Sciences and Research Centre, Tiruvalla, Kerala, India Seema Oommen seema.oommen@gmail.com No Burjeel Medical City, Musaffah, AbuDhabi, UAE Vidya Pai micro_vidya7417@rediffmail.com No Department of Microbiology, Yenepoya Medical College, Yenepoya University, Mangaluru, Karnataka, India