Monitoring antimicrobial resistance in care homes through wastewater surveillance: a scoping review

Antimicrobial resistance poses a growing threat, especially in care homes where older residents are particularly vulnerable due to frequent antibiotic use and comorbidities. Following the COVID-19 pandemic, there has been a growing focus on wastewater surveillance for detecting and monitoring pathogens in healthcare settings. This study followed the Joanna Briggs Institute scoping review framework to map the extent of available literature on wastewater-based epidemiological studies addressing antimicrobial resistance in care homes for older adults. Six electronic databases (Medline, Embase, Scopus, Web of Science, ProQuest, and Google Scholar) were searched from date of inception until August 26^th, 2024. The search strategy employed variations of the keywords: 'antimicrobial resistance', 'wastewater-based epidemiology', and 'care homes for older adults'. Studies were screened based on eligibility criteria, with data extracted by one researcher. Another researcher reviewed the charted data and resolved any queries. The search identified 83 studies, from which 11 studies, conducted between 2015 and 2024, were included. The studies used grab or composite sampling, combined with culture-based methods for bacterial identification, antimicrobial susceptibility testing, and molecular techniques such as polymerase chain reaction and whole-genome sequencing. Enterobacterales, including Escherichia coli and Klebsiella spp., were the most frequently detected, with high resistance rates, especially to some penicillins and cephalosporins. Despite the small sample sizes reported in this review, wastewater-based epidemiology shows promise in monitoring antibiotic-resistant bacteria in care home wastewaters, offering insights into trends and genetic diversity, with the potential to inform public health strategies and antibiotic stewardship programmes.