Heavy Metal and Petroleum Hydrocarbon Contaminants Promote Resistance and Biofilm Formation in Vibrio Species from Shellfish.

Shellfish are an essential component of the human diet, yet their safety is increasingly compromised by contamination with heavy metals, petroleum hydrocarbons, and pathogenic microorganisms, such as Vibrio, which pose significant health risks. This study examined shellfish samples from seafood markets, assessing the levels of heavy metals (e.g., cadmium, copper) and petroleum hydrocarbons, while isolating and identifying Vibrio species carried by the shellfish. The antimicrobial resistance profiles, resistance genes, and biofilm-forming capacities of these strains were further characterized. Results revealed significant seasonal fluctuations in heavy metal concentrations, with some samples exceeding regulatory limits, indicating potential health risks for long-term consumers. Likewise, Vibrio abundance and resistance varied seasonally, with a notable prevalence of multidrug-resistant strains, likely influenced by antibiotic misuse and environmental pressures in coastal regions. Correlation analyses suggested potential links between heavy metal contamination and Vibrio resistance, as well as biofilm formation, supporting the hypothesis that metal-induced stress may facilitate resistance gene transfer and enhance biofilm-mediated resistance. This study reveals the seasonal dynamics of antimicrobial resistance (AMR) in shellfish-derived Vibrio species and elucidates the dose-response effects of heavy metals and petroleum hydrocarbons, as well as their synergistic selection mechanisms. These findings provide a scientific foundation for assessing shellfish safety, deciphering AMR transmission, and developing ecosystem-based strategies for aquaculture monitoring.