Vol. 9, Issue 10, Part J (2025)

The study investigated anthrax outbreaks in Karnataka by isolating and characterizing Bacillus anthracis from livestock suspected cases across different districts. Ten samples, including blood, spleen, and ear tissues, were collected from animals and processed using standard culture techniques on BHI, PLET, and blood agar to obtain characteristic colonies. Gram staining revealed Gram-positive rod-shaped cells arranged in chains, confirming preliminary identification. Molecular confirmation was achieved through PCR amplification of the pXO2 gene, yielding consistent 846 bp amplicons across all isolates, thereby validating the presence of virulent plasmids. The purified PCR products were sequenced, and phylogenetic analysis was performed using MEGA software with the Neighbor-Joining method and Tamura-Nei model. The results demonstrated that Karnataka isolates clustered distinctly together, forming a clear lineage separate from global reference strains, suggesting localized lineage adaptation and limited gene flow with external populations. Minor intra-cluster variations indicated micro evolutionary changes within the South Indian strains. The study concludes that Bacillus anthracis strains circulating in Karnataka exhibit strong genetic relatedness highlighting the importance of continuous molecular surveillance and phylogenetic monitoring to understand transmission patterns and to reform local anthrax control strategies.