Wastewater-Based Surveillance of Antimicrobial Resistance Genes in Hospitals
Date
2024-01-04
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Abstract
Background: Antimicrobial resistance poses a significant threat to public health and healthcare-associated infections with antimicrobial-resistant organisms contribute to increased patient morbidity, mortality, and healthcare costs. We adapted wastewater-based surveillance (WBS) as a novel tool to quantify and longitudinally monitor the abundance of antimicrobial resistance genes (ARGs) comprehensively and inclusively in tertiary care hospitals. Methods: Wastewater was collected weekly from March 2022 to March 2023 from four Calgary hospitals: RGH (615 beds), PLC (517 beds), FMC (1100 beds), and ACH (141 beds). A Calgary wastewater treatment plant (WWTP) served as a community control (population ~1 million). DNA extracted from wastewater pellets was used to detect the following ARGs with qPCR: Clostridioides difficile (C. difficile 16S rRNA, tcdA, tcdB), vancomycin-resistant enterococci (vanA, vanB), and Gram-negative ARGs (blaNDM-like, blaVIM-like, mcr-like). ARG copy numbers were assessed as raw (copies/ mL of wastewater processed) and normalized with three fecal biomarkers (total bacterial 16S rRNA, Bacteroides HF183 16S rRNA, human 18S rRNA). Mann-Whitney comparisons were determined with GraphPad Prism (v9.0). Results: Across one year, all ARGS were detected in hospital and community wastewater with qPCR. Mean abundances of C. difficile 16S rRNA, tcdA, and tcdB normalized with bacterial 16S rRNA were respectively 1.5- to 62-, 1.4- to 6-, and 1- to 344-times greater in hospitals than the WWTP, but only significantly in RGH, PLC, and FMC (p<0.05). Mean 16S-normalized abundances of vanA and vanB were respectively 26- to 2953- and 1.7- 108-times higher in RGH, PLC, and FMC relative to the WWTP (p<0.0001). Mean 16S-normalized abundance of blaNDM-like was 8- to 184-times greater in all hospitals (p<0.01) and blaVIM-like was 2- to 95-times greater in PLC and FMC than the WWTP (p<0.0001). mcr-like resistance was only occasionally detected at low levels in hospitals and was considered non-significant. Conclusion: WBS is a novel tool that can be used in real time to monitor ARGs across a range of scales with the potential to augment antimicrobial stewardship and infection control programs and elucidate potential contributing factors of ARG selection and colonization.
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Keywords
Antimicrobial resistance, Wastewater, Hospital surveillance
Citation
Au, E. (2024). Wastewater-based surveillance of antimicrobial resistance genes in hospitals (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.