Metagenomic assembly provides a deep insight into the antibiotic resistome alteration induced by drinking water chlorination and its correlations with bacterial host changes

[Display omitted] •Drinking water chlorination altered bacterial antibiotic resistome.•Metagenomic assembly revealed co-occurrence of ARGs and MGEs.•Host shift played a major role in shaping antibiotic resistome during chlorination.•Chlorination contributed to the occurrence of some bacterial pathogens. Chlorination can contribute to the enrichment of specific antibiotic resistance genes (ARGs) in drinking water, but the underlying molecular ecological mechanisms remain unknown, which may hinder the assessment and control of the resulting health risks. In this study, metagenomic assembly and Resfams annotation were used to profile the co-occurrence patterns of ARGs, mobile genetic elements (MGEs) and their bacterial hosts, as well as the correlations of potential pathogens with the antibiotic resistome, in a full-scale drinking water treatment and transportation system. Seven ARG types involved in different resistance mechanisms occurred in drinking water and chlorination enhanced the total abundance of the ARGs (p