Alizarin enhancement of the abundance of ARGs and impacts on the microbial community in water

Abstract

Alizarin, a dyestuff from herbs, showed effective inhibition effects on pathogenic bacteria, and thus has been frequently used in the world as the main alternative to antibiotics in the treatment of inflammations and pathogen infections. However, it was unclear whether alizarin played key a role in antibiotic-induced antibiotic-resistant gene (ARG) alterations and impacted microbial community shifts in aquatic environments. In this study, the effects of alizarin or co-exposure of alizarin with antibiotics on the fate of ARGs, class 1 integron-integrase gene (intI1), and microbial populations in lake water were investigated, and the potential hosts for ARGs were analyzed. The results showed that the absolute abundance of 16s rRNA gene, ARGs (tetA, tetC, and qnrS), and intI1 were increased during the treatment of alizarin. The combination of alizarin and antibiotics was superior to alizarin in its ability to promote population growth of bacteria and induce ARGs. Additionally, alizarin more significantly altered the community composition of microorganisms in water, which resulted in differences in bacterial communities and functions.