AUTHOR=Gu Qihui , Sun Ming , Lin Tao , Zhang Youxiong , Wei Xianhu , Wu Shi , Zhang Shuhong , Pang Rui , Wang Juan , Ding Yu , Liu Zhenjie , Chen Ling , Chen Wei , Lin Xiuhua , Zhang Jumei , Chen Moutong , Xue Liang , Wu Qingping 

TITLE=Characteristics of Antibiotic Resistance Genes and Antibiotic-Resistant Bacteria in Full-Scale Drinking Water Treatment System Using Metagenomics and Culturing

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.798442

DOI=10.3389/fmicb.2021.798442

ISSN=1664-302X

ABSTRACT=<p>The contamination of antibiotic resistance genes (ARGs) may directly threaten human health. This study used a metagenomic approach to investigate the ARG profile in a drinking water treatment system (DWTS) in south China. In total, 317 ARG subtypes were detected; specifically, genes encoding bacitracin, multidrug, and sulfonamide were widely detected in the DWTS. Putative ARG hosts included <italic>Acidovorax</italic> (6.0%), <italic>Polynucleobacter</italic> (4.3%), <italic>Pseudomonas</italic> (3.4%), <italic>Escherichia</italic> (1.7%), and <italic>Klebsiella</italic> (1.5%) as the enriched biomarkers in the DWTS, which mainly carried bacitracin, beta-lactam, and aminoglycoside ARGs. From a further analysis of ARG-carrying contigs (ACCs), <italic>Stenotrophomonas maltophilia</italic> and <italic>Pseudomonas aeruginosa</italic> were the most common pathogens among the 49 ACC pathogens in the DWTS. The metagenomic binning results demonstrated that 33 high-quality metagenome-assembled genomes (MAGs) were discovered in the DWTS; particularly, the MAG identified as <italic>S. maltophilia</italic>-like (bin.195) harbored the greatest number of ARG subtypes (<italic>n</italic> = 8), namely, multidrug (<italic>n</italic> = 6; <italic>sme</italic>D, <italic>sem</italic>E, multidrug_transporter, <italic>mex</italic>E, <italic>sem</italic>B, and <italic>sme</italic>C), beta-lactam (<italic>n</italic> = 1; metallo-beta-lactamase), and aminoglycoside [<italic>n</italic> = 1; <italic>aph</italic>(3’)-IIb]. The strong positive correlation between MGEs and ARG subtypes revealed a high ARG dissemination risk in the DWTS. Based on the pure-culture method, 93 isolates that belong to 30 genera were recovered from the DWTS. Specifically, multidrug-resistant pathogens and opportunistic pathogens such as <italic>P. aeruginosa</italic>, <italic>Bacillus cereus</italic>, and <italic>S. maltophilia</italic> were detected in the DWTS. These insights into the DWTS’s antibiotic resistome indicated the need for more comprehensive ARG monitoring and management in the DWTS. Furthermore, more effective disinfection methods need to be developed to remove ARGs in DWTSs, and these findings could assist governing bodies in the surveillance of antibiotic resistance in DWTSs.</p>