Bioaccumulation of Three Typical Antibiotics in the Edible Bivalve Tegillarca granosa: Potential Mechanisms and Human Health Implications.

Marine bivalves may be exposed to various terrigenous antibiotics, while empirical evidence supporting antibiotic accumulation and potential health risks remains limited. Thus, the accumulation of three typical antibiotics, ciprofloxacin (CIP), erythromycin (ERY), and oxytetracycline (OTC), in an edible bivalve species, blood clam (Tegillarca granosa), was measured in this study. Moreover, microbiological target hazard quotients (mTHQs) and dietary exposure doses of the human gut microbiota (DEGMs) were estimated to assess food safety risks to consumers. Furthermore, the detoxification processes, oxidative status, and energy metabolism in the gill and hepatopancreas were analyzed to explore their potential associations with antibiotic accumulation. Obtained data demonstrated that 28 days of exposure to environmentally realistic levels resulted in significant antibiotic accumulation in blood clams. Fortunately, the mTHQs of antibiotics were far below the critical value, suggesting a low likelihood of direct inhibition of the human intestinal microbiota. Nevertheless, as the DEGM value exceeded the lower boundary of the minimal selective concentration, consuming CIP-contaminated clams may pose a potential concern about antibiotic resistance selection in the intestinal microbiome. Additionally, the contents (or activity) of detoxification enzymes, the expressions of detoxification genes, and the levels of oxidative stress of detoxification organs were all notably altered by antibiotic exposure. Moreover, significant shifts in energy supply were also detected in antibiotic-treated clams. Overall, these findings suggest that antibiotic accumulation in blood clams mag be associated with alterations in detoxification, oxidative status, and energy metabolism, providing insights into the potential toxicological and food safety implications of antibiotic exposure in bivalves.