Abstract
Alongside antibiotic resistance, co-selection of antibiotics, biocides, and metal resistance is a growing concern. While hospital wastewater is considered a hotspot for antibiotic-resistant bacteria (ARB) and genes (ARGs), the scenario in India, one of the biggest consumers of antibiotics, remains poorly described. In this study, we used metagenomic sequencing to characterize ARGs and biocide/metal resistance genes (BMRGs) in four wastewater treatment plants (WWTPs) in Jaipur City of India. We observed a significantly lower richness and abundance of ARGs in the influent of a WWTP exclusively receiving hospital wastewater when compared to other three WWTPs involving municipal wastewater treatment. Several tetracycline and macrolide-lincosamide-streptogramin resistance genes were enriched in influents of these three municipal wastewater-related treatment plants, whereas hospital wastewater had a higher abundance of genes conferring resistance to disinfectant-related compounds such as synergize and wex-cide-128, reflecting the patterns of antibiotic/disinfectant use. Of note, in the wastewater system with more chemicals, there was a strong correlation between the numbers of ARGs and BMRGs potentially harbored by common hosts. Our study highlights significant influxes of ARGs from non-hospital sources in Jaipur City, and thus more attention should be paid on the emergence of ARGs in general communities.
Highlights
Antibiotic resistance is a long-standing and ever worsening issue, posing a serious threat to human health worldwide (Rivera-Tapia, 2003; Ventola, 2015; Ben et al, 2019)
Physico-chemical parameters conducted for water quality assessment showed that the influents of three wastewater treatment plants (WWTPs) with municipal wastewater involvement (MNIT, Jawahar Circle (JC) and JNU) had a significantly higher Biochemical oxygen demand (BOD), Chemical oxygen demand (COD), and Total suspended solids (TSS) (Welch’s t-test, p < 0.05) than the influent of Eternal Heart Critical Care Hospital (EHCC) that exclusively receives hospital wastewater, but this trend was not found in their effluents (Supplementary Table S1)
As compared to the respective influents, the richness of antibiotic resistance genes (ARGs) and biocide/metal resistance genes (BMRGs) significantly decreased in sludges and effluents of Malaviya National Institute of Technology Jaipur (MNIT), JC, and JNU, but not EHCC (Figure 1A)
Summary
Antibiotic resistance is a long-standing and ever worsening issue, posing a serious threat to human health worldwide (Rivera-Tapia, 2003; Ventola, 2015; Ben et al, 2019). Antibiotic resistance can be co-selected by the antibacterial biocides and metals when bacteria harbor genes conferring resistance to both types of compounds (Pal et al, 2015). Various compounds, including antimicrobial residues, biocides and heavy metals flow into wastewater, further providing a fertile environment for antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs; Karkman et al, 2018). The ARB/ ARGs removal efficiency differs among different WWTPs and is affected by various factors These include wastewater treatment processes (Kucukunsal and Icgen, 2020; Qin et al, 2020), disinfection methods (Barancheshme and Munir, 2018), the types of ARGs present (Li et al, 2015), and WWTP size (Harnisz et al, 2020). There is a consensus of findings that the WWTP discharges would increase the ARGs abundance in receiving river (Berglund et al, 2015; Brown et al, 2020)
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