Untreated HWWs Emerged as Hotpots for ARGs

Hospital wastewaters (HWWs) are reported to be hotspots for antibiotics and antibiotic-resistant bacteria. However, limited information involves the impact of these effluents on dissemination of antibiotic-resistance genes (ARGs). In this study, therefore, seasonally collected HWWs were monitored for overall bacterial load and seven ARGs aadA, tetA, cmlA, sul1, qnrS, ermB and bla CTX-M by using quantitative polymerase chain reaction method. Overall bacterial 16S rRNA copy number was found to be the lowest in winter with 103 copy number/mL, while the highest copy number, with 105 copy number/mL, was observed in both summer and spring. All hospitals tested displayed similar seasonal ARG copy number profile of aadA > tetA > cmlA ≈ sul1 > ermB ≈ qnrS > bla CTX-M. The results indicated that untreated HWWs were hotspots for ARGs and required attention before discharging into public sewer.