[Antibiotic Residue in Environmental Water in Vietnam]

The increasing prevalence of antimicrobial resistance (AMR) has caused intractable infections worldwide. Nearly 50% of the healthy population of Southeast Asia carries extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. The overuse of antimicrobial agents in the agriculture, aquaculture, and medical care sectors causes environmental pollution, facilitating the spread of AMR. However, there is a lack of data pertaining to antimicrobial residues in environmental water in such regions. We investigated a total of 49 chemicals, including β-lactams, sulfonamides, quinolones, and tetracyclines. Water samples were collected from rivers in city centers, and ponds in livestock and aquaculture farms, in Ha Noi, Thai Binh, and Can Tho in Vietnam. We detected antimicrobial agents at 87 of 111 sampling sites (78.4%). Among the target analytes, sulfamethoxazole, sulfamethazine, trimethoprim, cephalexin, and ofloxacin were detected frequently. The residual levels of each antimicrobial agent ranged from 0.1 to 10000 ng/L. Moreover, we detected multi-drug resistant E. coli in fishes sampled from these rivers, suggesting unwanted effects of antimicrobial residues in the environment.