Metagenomic analysis of microbiota and antibiotic resistome in household activated carbon drinking water purifiers

Existing drinking water treatment systems have limited ability to control emerging contaminants such as antibiotic resistance genes (ARGs). Household activated carbon water purifiers (HWPs) are convenient measures to assure drinking water quality. However, ARGs distribution in HWPs has not been reported. Here, ARGs, mobile genetic elements (MGEs) and bacteria communities were profiled in tap water (TW), filter water (FW) and activated carbon (AC) biofilm from six kinds of HWPs after 80 days operation, using metagenomics. Results showed that the bacteria community diversities in FW and AC were higher than those in TW. A total of 88, 116 and 80 ARG subtypes were detected in TW, AC and FW, respectively. The AC structure was an important factor influencing the bacterial communities and ARG profiles in FW. The network analysis revealed the co-occurrence patterns between ARGs and bacteria. SourceTracker analyses showed AC biofilms were important contributors of microbes (29-79%) and ARGs (17-53%) in FW. Moreover, MGEs e.g. pBBta01, pMKMS02 and pMFLV01 plasmids, and ISMysp3 had significant co-occurrence patterns with ARGs in the AC biofilms. This study helps to understand the actual purification effect of HWPs and provides a theoretical reference for the management and control of ARGs pollution in domestic drinking water.

Automated summary

The existing drinking water treatment systems have limited ability to control emerging contaminants, such as antibiotic resistance genes (ARGs). Household activated carbon water purifiers (HWPs) are a convenient measure to ensure drinking water quality, but the distribution of ARGs in HWPs has not been reported. This study revealed that the bacterial community diversities in filter water and activated carbon were higher than those in tap water, and the structure of activated carbon played an important role in influencing the bacterial communities and ARG profiles in filter water. Additionally, co-occurrence patterns between ARGs and bacteria were detected, and SourceTracker analyses indicated that activated carbon biofilms were significant contributors of microbes and ARGs in filter water.