Department of Medical Research, E-Da Hospital, I-Shou University, Kaohsiung, Taiwan.
Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan.
Ecotoxicol Environ Saf. 2023 Sep 15;263:115372. doi: 10.1016/j.ecoenv.2023.115372. Epub 2023 Aug 22.
Antimicrobial-resistant Escherichia coli in the aquatic environments is considered a strong indicator of sewage or animal waste contamination and antibiotic pollution. Sewer construction and wastewater treatment plant (WWTP) infrastructure may serve as concentrated point sources of contamination of antibiotic-resistant bacteria and antibiotic resistance genes. In this study, we focused on the distribution of antimicrobial-resistant E. coli in two rivers with large drainage areas and different urbanisation levels. E. coli from Kaoping River with drainage mainly from livestock farming had higher resistance to antibiotics (e.g. penicillins, tetracyclines, phenicols, aminoglycosides, and sulpha drugs) and presented more positive detection of antibiotic-resistance genes (e.g. ampC, bla, tetA, and cmlA1) than that from Tamsui River. In Kaoping River with a lower percentage of sewer construction nearby (0-30%) in contrast to a higher percentage of sewer construction (55-92%) in Tamsui River, antimicrobial-resistant E. coli distribution was related to livestock farming waste. In Tamsui River, antimicrobial resistant E. coli isolates were found more frequently in the downstream drainage area of WWTPs with secondary water treatment than that of WWTPs with tertiary water treatment. The Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR showed that the fingerprinting group was significantly related to the sampling site (p < 0.01) and sampling date (p < 0.05). By utilising ERIC-PCR in conjunction with antibiotic susceptibility and antibiotic-resistance gene detection, the relationship among different strains of E. coli could be elucidated. Furthermore, we identified the presence of six extra-intestinal pathogenic E. coli isolates and antibiotic-resistant E. coli isolates near drinking water sources, posing a potential risk to public health through community transmission. In conclusion, this study identified environmental factors related to antibiotic-resistant bacteria and antibiotic-resistance gene contamination in rivers during urban development. The results facilitate the understanding of specific management of different waste streams across different urban areas. Periodic surveillance of the effects of WWTPs and livestock waste containing antibiotic-resistant bacteria and antibiotic-resistance genes on river contamination is necessary.
水生环境中的抗微生物大肠埃希氏菌被认为是污水或动物粪便污染和抗生素污染的强烈指示物。污水管道建设和废水处理厂 (WWTP) 基础设施可能成为抗生素耐药细菌和抗生素耐药基因集中污染的点源。在这项研究中，我们专注于具有不同城市化水平的两条大流域中抗药性大肠埃希氏菌的分布。主要来自畜牧业的高屏溪的大肠埃希氏菌对抗生素（例如青霉素类、四环素类、酚类、氨基糖苷类和磺胺类药物）的耐药性更高，并且更有可能检测到抗生素耐药基因（例如 ampC、bla、tetA 和 cmlA1），而淡水河的大肠埃希氏菌则不然。在高屏溪，附近污水管道建设的比例较低（0-30%），而淡水河的污水管道建设比例较高（55-92%），抗药性大肠埃希氏菌的分布与畜牧业废物有关。在淡水河，二级水处理 WWTP 下游排水区比三级水处理 WWTP 更频繁地发现抗药性大肠埃希氏菌分离株。肠杆菌重复基因间共识 (ERIC) PCR 显示，指纹图谱与采样地点（p < 0.01）和采样日期（p < 0.05）显著相关。通过利用 ERIC-PCR 结合抗生素敏感性和抗生素耐药基因检测，可以阐明不同大肠埃希氏菌菌株之间的关系。此外，我们在饮用水源附近发现了六种肠外致病性大肠埃希氏菌分离株和抗药性大肠埃希氏菌分离株，这对通过社区传播对公众健康构成潜在威胁。总之，本研究确定了城市发展过程中河流中与抗生素耐药细菌和抗生素耐药基因污染相关的环境因素。这些结果有助于理解不同城市地区不同废物流的具体管理。有必要定期监测 WWTP 和含有抗生素耐药细菌和抗生素耐药基因的畜牧业废物对河流污染的影响。
