Pharmaceutical concentrations and antimicrobial activity using hypersusceptible <i>Escherichia coli</i> lacking TolC component of multidrug efflux system in the Ayase River in Japan

The pharmaceutical concentrations and antimicrobial activity in the Ayase River were investigated. water sources of are agricultural wastewater effluent from septic tanks during irrigation season a sewage treatment plant non-irrigation season. Acetaminophen, bezafibrate, carbamazepine, clarithromycin, diphenhydramine levels range 1.9–495 ng/L. During season, higher downstream than upstream due to inflow areas. However, since most tanks, extremely high downstream. at same as those Arakawa River, which was polluted by Japan’s largest plant. This concentration non-irrigated found only but not nearby Nakagawa Furutone rivers, both urban sources. maximum clarithromycin predicted no-effect for green algae, indicating that may affect aquatic organisms. Antimicrobial analysis using hypersusceptible Escherichia coli lacking TolC component multidrug efflux system revealed river had activity, suggesting potential risks, such bactericidal action development antibiotic resistance water.