Distribution of antibiotic resistance genes in an agriculturally disturbed lake in China: Their links with microbial communities, antibiotics, and water quality.

In this study, six antibiotic resistance genes (ARGs), one mobile genetic element (int1), and their relation with microbial communities, antibiotics, and water quality were investigated in and around of an agriculturally disturbed lake, namely, Lake Honghu. The ARGs and int1 in the research area had a 100 % detection frequency in each sample during two sampling times. The ARGs were higher in the rivers and inlets than in Lake Honghu. Sul1 was the main ARG in this area. Antibiotics, nutrients, and dissolved oxygen were significantly, positively, and negatively correlated with nearly all of the ARGs, respectively. This finding suggests that reducing antibiotics and the eutrophication level could reduce the risk of ARGs. Microbial community shift had the most direct contribution to ARG variation. However, when the indirect effect was considered, environmental factors contributed 34 % to the ARGs' variance, the microbial community contributed 28 %, and their joint effect contributed 27 % to the ARG profiles. The abundance of Firmicutes, Gemmatimonadetes, Proteobacteria, etc. and their positive correlation with ARGs were significant, suggesting that these phyla probably carry ARGs. The study provides a systematic profile of ARG distribution and dissemination in a typical Chinese lake and new ideas to control this emerging contaminant in lakes.