Occurrence and Consumption of Antibiotics in Northern Malaysia: A Wastewater Analysis

ABSTRACT Antibiotics are widely used in human and veterinary medicine and are continuously introduced into aquatic environments through wastewater discharge. This study applied wastewater‐based epidemiology to investigate the occurrence, fate and consumption of the four last‐resort antibiotics: colistin, polymyxin B, vancomycin and meropenem in northern Malaysia from December 2021 to January 2022. Influent and effluent samples were collected from 18 sewage treatment plants and analysed using solid‐phase extraction coupled with liquid chromatography‐mass spectrometry. All targeted antibiotics were detected, predominantly at concentrations below 1 μg/L, with meropenem and polymyxin B showing the highest detection frequencies. Estimated per capita consumption indicated greater usage of polymyxin B and vancomycin compared to meropenem and colistin. The persistence of certain antibiotics in treated effluents highlights limitations of conventional biological treatment and underscores the need for improved monitoring and regulatory strategies to mitigate environmental and antimicrobial resistance risks.