Exploration of activated sludge resistome using metagenomics

Highlights: @@@ Antimicrobial resistance is global threat to public health. @@@ Effluent treatment plants act as hotspot for resistance dissemination. @@@ Effluent treatment plants encompass complex resistome. @@@ Secondary metabolite encoding genes were present -- Abstract: Antibiotic resistance is a global problem. In India poor waste management and inadequate sanitary are key factors which encourage the dissemination of antimicrobial resistance. Microbial biodiversity serves as an invaluable source for diverse types of bioactive compounds that encompass most of the pharmaceuticals to date. Therefore, in this study, we used the metagenomic approach for the surveillance of antibiotic resistance genes, drug resistant microbes and mobile-genetic elements in two activated sludge metagenome samples collected from Ankleshwar, Gujarat, India. Proteobacteria were found to be the most abundant bacteria among the metagenome analyzed. Twenty-four genes conferring resistance to antibiotics and heavy metals were found. Multidrug resistant @@@ESKAPE pathogens@@@ were also abundant in the sludge metagenome. Mobile genetic elements like IncP-1 plasmid pKJK5, IncP-1beta multi resistance plasmid and pB8 were also noticed in the higher abundance. These plasmids play an important role in the spread of antibiotic resistance by the horizontal gene transfer. Statistical analysis of both metagenome using STAMP software confirmed presence of mobile genetic elements such as gene transfer agents, phages, Prophages etc. which also play important role in the dissemination of antibiotic resistant genes.