Emergence of virulent, multidrug-resistant, and genetically diverse Aeromonas hydrophila in foods of animal and aquatic origin from tribal regions of Northeastern India.

Aeromonas hydrophila is an emerging zoonotic foodborne bacterial pathogen that causes gastro-intestinal and extra-intestinal infections in humans. A total of 361 samples including water (n = 195) and foods of animal and aquatic origin (n = 166) collected from tribal dwelling areas of Northeastern India were screened for the microbiological presence of A. hydrophila. Upon presumptive identification and molecular confirmation, the overall occurrence was 8.31% (30/361) with the highest rate observed in edible snails (13/38, 38.24%), followed by fish (4/14, 28.57%), pork (5/18, 27.78%), chicken (5/100, 20.0%) and domestic tap water (3/195, 1.54%). Multidrug resistance was observed in 13.33% (4/30) of the isolates, with the highest phenotypic resistance observed against amoxicillin-clavulanic acid (15/30, 50.00%). Phenotypic virulence, ascertained using adhesion forming ability, identified five isolates with strong ability out of 76.67% (23/30) isolates which harboured the ability to form adhesions on abiotic surfaces. Serine protease (ser) gene featured as the predominant virulence gene (23/30, 76.67%) among the isolates followed by act (16/30, 53.33%) which codes for cytotoxic toxin. Heatmap analysis with hierarchical clustering as well as Enterobacterial Repetitive Intergenic Consensus (ERIC) and Random Amplified Polymorphic DNA (RAPD)-based fingerprinting indicated wide genetic diversity among the isolates. Overall, the study highlights the emergence and circulation of adhesion-forming, multidrug-resistant A. hydrophila strains that carry clinically important virulence genes. These findings raise a potential public health concern for the tribal population of Northeastern India, known for their distinct culinary practices and food habits.