Overexpression of antibiotic resistance genes in hospital effluents over time

Abstract

Objectives: Effluents contain a diverse abundance of antibiotic resistance genes that augment the resistome of receiving aquatic environments. However, uncertainty remains regarding their temporal persistence, transcription and response to anthropogenic factors, such as antibiotic usage. We present a spatiotemporal study within a river catchment (River Cam, UK) that aims to determine the contribution of antibiotic resistance gene-containing effluents originating from sites of varying antibiotic usage to the receiving environment. Methods: Gene abundance in effluents (municipal hospital and dairy farm) was compared against background samples of the receiving aquatic environment (i.e. the catchment source) to determine the resistome contribution of effluents. We used metagenomics and metatranscriptomics to correlate DNA and RNA abundance and identified differentially regulated gene transcripts. Results: We found that mean antibiotic resistance gene and transcript abundances were correlated for both hospital (ρ = 0.9, two-tailed P <0.0001) and farm (ρ = 0.5, two-tailed P <0.0001) effluents and that two β-lactam resistance genes (blaGES and blaOXA) were overexpressed in all hospital effluent samples. High β-lactam resistance gene transcript abundance was related to hospital antibiotic usage over time and hospital effluents contained antibiotic residues. Conclusions: We conclude that effluents contribute high levels of antibiotic resistance genes to the aquatic environment; these genes are expressed at significant levels and are possibly related to the level of antibiotic usage at the effluent source.

Genomic epidemiology of multidrug‐resistant Gram‐negative organisms

“…119 In support of hospital practices playing a role in promoting the environmental resistome, they found that catchment water from hospitals was enriched for ␤-lactamases compared with other sites and that hospital effluent ␤-lactamase levels correlated with hospital antibiotic usage over time. 119 Water sources within the hospital have also been implicated as a location where resistance transfer could occur. Recent work investigating the role of sinks, drains, and other hospital waterways is motivated by several reports of outbreaks where resistant organisms have been isolated from these sites.…”

“…used a combined metagenomic/metatranscriptomic approach to measure resistance gene abundance and expression, as well as antibiotic concentrations in effluents from different sites that varied in antibiotic use . In support of hospital practices playing a role in promoting the environmental resistome, they found that catchment water from hospitals was enriched for β‐lactamases compared with other sites and that hospital effluent β‐lactamase levels correlated with hospital antibiotic usage over time . Water sources within the hospital have also been implicated as a location where resistance transfer could occur.…”

“…Several groups have used metagenomics approaches to detect resistance markers and mobile genetic elements in hospital wastewater. [117][118][119][120][121] Growing evidence that environmental water organisms can take up clinically important resistance markers when exposed to these wastewaters further bolsters this hypothesis. 121 Recently, Rowe et al used a combined metagenomic/metatranscriptomic approach to measure resistance gene abundance and expression, as well as antibiotic concentrations in effluents from different sites that varied in antibiotic use.…”

Fecal pollution explains antibiotic resistance gene abundances in anthropogenically impacted environments

“…Concerns about the elevated levels of antibiotic resistant bacteria and resistance genes in the receiving environments of treated sewage have been raised in several publications (Berendonk et al, 2015;Eckert et al, 2018;Martinez, 2008Martinez, , 2009Rowe et al, 2017). However, based on only abundance data it is difficult to determine whether the increase is explained by selection and dissemination to the resident microbiota or by constant input of fecal bacteria.…”

“…Metagenomic studies on human impacted environments were searched from the literature and six studies where the sequencing data was available were selected and downloaded from either SRA or ENA (Bengtsson-Palme et al, 2014;Chu et al, 2017;Kristiansson et al, 2011;Lekunberri et al, 2018;Marathe et al, 2017;Ng et al, 2017;Rowe et al, 2016Rowe et al, , 2017. The studies included samples from river and lake sediments, WWTP and hospital effluents and river water.…”