Genomic insights into antibiotic-resistant Vibrio species from clinical and coastal environmental sources in India

The occurrence and impact of pathogenic Vibrio sp. in coastal waters are strongly influenced by climate change indicators such as ocean warming, sea-level rise, and extreme weather events. This study aimed to compare the virulence and antimicrobial resistance (AMR) profiles of Vibrio cholerae from clinical and environmental sources across India's coastal regions. We also examined pathogenic traits in other marine Vibrio sp. We hypothesized that Vibrio spp. from different environments would show distinct virulence and AMR patterns shaped by their ecological context. To investigate this, we conducted antimicrobial susceptibility testing and whole-genome sequencing (WGS) on both clinical and environmental isolates. Our findings reveal that environmental V. cholerae from coastal waters possess genes promoting host adhesion and haemolytic activity. Similarly, Vibrio alginolyticus and Vibrio vulnificus harboured virulence factors aiding tissue attachment and invasion. Resistance profiling showed environmental V. cholerae were resistant to fluoroquinolones and macrolides, while clinical isolates were resistant to aminoglycosides and sulphonamides. The presence of antibiotic-resistant Vibrio in marine environments poses a significant public health risk, especially given frequent human interactions with coastal waters for recreation, fishing, and transport. Climate change may exacerbate the proliferation and movement of these pathogens across aquatic and terrestrial systems, increasing the likelihood of human exposure. Moreover, the potential for horizontal gene transfer of resistance genes among pathogenic marine bacteria further highlights the need for surveillance and mitigation strategies to address the growing threat of AMR in marine ecosystems.