Urban-rural disparities in antibiotic and disinfectant use and their socioeconomic associations by wastewater surveillance.

Understanding urban-rural and socioeconomic disparities in antibiotic and disinfectant consumption is important for effective antimicrobial resistance management. In this study, we applied wastewater-based epidemiology (WBE) to systematically assess per capita antibiotic and disinfectant consumption across 22 wastewater treatment plants in Dalian, China. The results revealed marked urban-rural disparities in both total consumption and medication structures across the monitored periods. Total antibiotic and disinfectant consumption in urban areas was significantly higher than in rural areas. Urban populations showed greater use of higher-cost, broad-spectrum antibiotics such as azithromycin, whereas rural populations relied more heavily on lower-cost and more accessible antibiotics such as phenoxymethylpenicillin. Although antibiotic consumption increased markedly during certain observation periods, these peaks subsequently returned toward baseline levels. Socioeconomic analysis showed that urban total antibiotic consumption was negatively correlated with the Composite Development Index (CDI), indicating higher antibiotic consumption in economically disadvantaged communities, potentially associated with differences in healthcare resources and diagnostic capacity. In contrast, rural disinfectant use was positively associated with the CDI, highlighting that routine sanitation in rural contexts remains strongly constrained by local economic infrastructure. These findings suggest that population-level antimicrobial use may be associated with socioeconomic disparities and differences in healthcare accessibility.