Risk assessment of antibiotic resistance genes in the drinking water system

• Published in: The Science of the total environment Vol. 800; p. 149650
• Main Authors: Hu, Yaru, Jiang, Lei, Sun, Xiaoyan, Wu, Jianqiang, Ma, Lei, Zhou, Yanbo, Lin, Kuangfei, Luo, Yi, Cui, Changzheng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.12.2021
• Subjects: antibiotic resistance; Antibiotic resistance genes; chlorine; Chlorine-resistant; Drinking water system; environment; genes; humans; Pseudomonas aeruginosa; Resistance risk ranking in drinking water system (R3DW); risk; Risk assessment; Trace level antibiotics; water reservoirs; water treatment; Resistance risk ranking in drinking water system (R3DW); Trace level antibiotics; Antibiotic resistance genes; Chlorine-resistant; Drinking water system; Risk assessment
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2021.149650

Antibiotic resistance genes (ARGs) are extensively detected in various environmental media, whose risk assessment in the drinking water systems has not been comprehensive. This study established a new risk assessment of ARGs in the drinking water systems, considering the chlorine-resistance ability, transferability, and ARGs harboring potential of pathogens. The risk of ARGs in a typical drinking water reservoir was also evaluated based on the detection of ARGs and antibiotic-resistant bacteria (ARB). Fourteen ARGs were detected with a relative concentration range of 10-4–10-3 (ARGs/16S rRNA gene). Five isolated ARB were identified as human opportunistic pathogens, one of which (Pseudomonas aeruginosa HLS-6, CCTCC AB 2017269) is resistant to hundreds of milligrams per liter levels of antibiotics and low-level chlorine. This result indicated that ARB tolerant to high-levels of antibiotics could be isolated from environments containing trace levels of antibiotics. Moreover, complete genome sequencing confirmed the inclusion of ARGs (sul1, aadA2) on the class I integron in HLS-6, indicating that the risk of ARGs in this drinking water reservoir could be classified as resistance risk ranking in drinking water system 1 (R3DW 1). The risk assessment of ARGs in this study provides a clear understanding of ARG risk in drinking water systems. The results reveal that the ARGs and ARB contamination of drinking water reservoirs pose significant challenges for drinking water treatment efficiency and affect drinking water safety. [Display omitted] •Sulfonamides ARGs were the dominant type.•Five isolated ARB were identified as human opportunistic pathogens.•ARB from trace-level-antibiotic environment show high-level antibiotics resistance.•A new risk assessment system of ARG in drinking water system is established.•The tolerance to chlorine is a vital factor in the risk assessment of ARGs.