The emergence of antibiotic resistance genes (ARGs) and opportunistic pathogens (OPs) in drinking water system posed potential risks to human health. However, the occurrence of ARGs and OPs in drinking water biofilms is still at its infancy. In this study, we investigated the occurrence of ARGs and OPs in both water and biofilm samples from a drinking water system, and the correlation between ARGs and microbial communities was analyzed. The quantitative PCR results showed that the drinking water treatment process effectively decreased the absolute abundances of ARGs. However, the relative concentration of ARGs did not show a significant difference between raw water and treated water samples. Compared with bulk water and tap water samples, biofilms had higher relative abundances of ARGs. 16 S Illumina Miseq sequencing results showed that microbial communities of biofilms were distinguished with water samples. Meanwhile, qPCR results of OPs also showed that biofilms had higher relative abundances of OPs compared with water samples. Furthermore, the Spearman correlation analysis indicated that Dechloromonas, Desulfovibrio, Methylobacterium and Propionivibrio correlated well with the relative abundance of ARGs. The absolute concentrations of OPs and ARGs also showed a significant correlation. Results of this study suggest that biofilms could serve as the reservoirs for the spread of ARGs and the interaction between biofilms and bulk water requires further research.

饮用水系统中抗生素抗性基因（ARG）和机会病原体（OPs）的出现对人类健康构成了潜在风险。然而，饮用水生物膜中ARG和OP的发生仍处于起步阶段。在这项研究中，我们调查了饮用水系统中水和生物膜样品中ARGs和OPs的发生，并分析了ARGs与微生物群落之间的相关性。定量PCR结果表明，饮用水处理过程有效降低了ARGs的绝对丰度。但是，ARG的相对浓度在原水和处理后的水样品之间没有显示出显着差异。与散装水和自来水样品相比，生物膜具有较高的ARGs相对丰度。16 S Illumina Miseq测序结果表明，水样可以区分生物膜的微生物群落。同时，OPs的qPCR结果还显示，与水样品相比，生物膜具有更高的OPs相对丰度。此外，Spearman相关分析表明Dechloromonas，Desulfovibrio，Methylobacterium和Propionivibrio与ARGs的相对丰度有很好的相关性。OP和ARG的绝对浓度也显示出显着的相关性。这项研究的结果表明，生物膜可以作为ARGs扩散的储层，生物膜与大量水之间的相互作用需要进一步的研究。