Assessment of community-wide antimicrobials usage in Eastern China using wastewater-based epidemiology.

Wastewater-based epidemiology (WBE) has potential to identify the epidemiological links between people, animals, and the environment, as part of antimicrobial resistance (AMR) surveillance. In this study, we investigated six wastewater treatment plants (WWTPs) serving six communities located in two regions in Eastern China: Site A in Zhejiang and site B in Jiangsu province to assess the public use of antimicrobial agents (AA). Fifty antimicrobials and 24 of their metabolites were quantified using ultraperformance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UPLC-MS/MS). Spatiotemporal trends were established for measured concentrations, daily loads, and population-normalised daily loads. Daily AA mass loads varied between 1.6 g/day and 324.6 g/day reflecting the WWTP scales, with macrolides and ß-lactams showing the highest overall environmental burden at 223.7 g/day and 173.7 g/day, respectively. Emissions of antibiotic residues from manufacturing have been observed, with the peak daily load 12-fold higher than the overall load from a community serving a population of over 600,000. Community exposure levels of 225.2 ± 156.2 mg/day/1000 inhabitant and 351.9 ± 133.5 mg/day/1000 inhabitant were recorded in site A and B, respectively. Paired parent-metabolites analysis identified a large proportion (64-78%) of un-metabolised metronidazole and clindamycin at site B, indicating improper disposal of unused drugs either in the community or in livestock production. Consumption levels, calculated via WBE, suggested relatively low antimicrobial usage in Eastern China compared to other areas in China. This first application of WBE in Eastern China to assess the community-wide exposure to AAs has potential to inform regional antimicrobial stewardship.

Spatiotemporal urban water profiling for the assessment of environmental and public exposure to antimicrobials (antibiotics, antifungals, and antivirals) in the Eerste River Catchment, South Africa.

Antimicrobial agent (AA) usage, excretion, and persistence are all important factors in association with the occurrence and dissemination of antimicrobial resistance. Urban water profiling was utilised in the Eerste River catchment (South Africa) to establish AA usage in a region where comprehensive prescription records were not readily available and where portions of the community did not have sufficient access to sanitation. This technique enabled the environmental exposure to be quantified throughout the catchment area and the identification of contamination hotspots. Monitoring occurred over a 11-month period. 812 samples were processed using UPLC-MS/MS for the quantitation of 56 antimicrobials and 26 of their metabolites. Spatiotemporal trends were established, with consideration to community behaviour, seasonal changes, and physiochemical properties of the analytes. The Eerste River samples collected upstream from the town of Stellenbosch had the lowest AA loads (<4 g/day), unafflicted by industrial presence and with only small impact from farming activities. This was followed by sites downstream from a wastewater treatment plant (serving 178 K people). The measurement of low AA loads (influent: 500-800 g/day and effluent 50-100 g/day), indicates a high efficiency of wastewater treatment, allowing for an effective reduction of AA and a lower environmental burden. This is compared to river sites that receive untreated waste from communities in informal settlements (6-12 K people) that are not connected to the sewer infrastructure (with AA levels accounting for 100-600 g/day). Temporal trends exhibited reduced daily loads during the summer to early autumn (Nov-May). This is likely due to seasonal patterns in community health and/or notable changes in rainfall and temperatures at the sampling locations throughout the year. However, weather patterns are also important to consider - particularly for the river sites. South Africa has notable rainfall and temperature seasonality. Antiretrovirals (ARV), emtricitabine and lamivudine, were the most prevalent drugs throughout the monitoring campaign, followed by tuberculosis drugs and sulfonamides. ARVs were, however, effectively reduced via wastewater treatment processes (>97%). This was also the case for beta-lactams, nitrofurantoin, and trimethoprim. The treatment efficacy for other drugs was more variable, that did not appear to have temporal significance.