Occurrence of β-Lactam Resistance Genes and Plasmid-Mediated Resistance Among Vibrios Isolated from Southwest Coast of India.

Antimicrobial resistance (AMR) is a serious global threat driven by the overuse of drugs in humans, animals, as well as the contamination of natural environments with antimicrobial residues. In recent years, the rise of community-acquired infections resistant to antibiotics has drawn renewed attention to the environmental compartment, in particular for pathogens found in aquaculture systems. We quantified the prevalence of antibiotic resistance in Vibrios isolated from the Cochin Estuary as well as the adjoining shrimp farms, and seafood from markets. A total of 280 Vibrio strains were subjected to antimicrobial susceptibility testing and screened for the presence of blaTEM, blaCTX-M, and blaNDM-1 genes. All strains identified were resistant to at least three antimicrobials, and the percentage of drugs resistant per strain ranged from 16% up to 60%. All the strains from the estuary were resistant to amoxicillin, ampicillin, cephalothin, and colistin. Similarly, strains isolated from seafood were resistant to enrofloxacin, furazolidone, and trimethoprim, and all strains from shrimp farms were resistant to colistin. Plasmid-mediated antibiotic resistance was observed in 21% of the strains. In addition, the presence of blaNDM-1 gene was confirmed in 22.85% of the strains. The presence of multiple resistant phenotypes in vibrios, including resistance to last-resort compounds in domestic food sources, raises serious concerns for public health in the Cochin Estuary. Although localized in nature, our findings also have vital implications for the spread of AMR internationally, given the prominence of South India for seafood exports.