Removal of antibiotic resistance genes in wastewater treatment plants and their distribution in selected Asian communities.

This study evaluated the reduction of selected antibiotic resistance genes (ARGs) in a wastewater treatment plant (WWTP) using conventional activated sludge and assessed the distribution of ARGs in selected Asian communities. Set A samples (n = 21) were collected weekly from May to July 2020 at the influent, secondary-treatment, and effluent stages of a WWTP in Japan, whereas Set B samples (n = 40) were collected between 2022 and 2023 from sites in Japan, the Philippines, Vietnam, and Thailand. Samples were analyzed using a high-throughput quantitative polymerase chain reaction on the Biomark HD System, targeting fecal indicators, mobile genetic element, and ARGs. In Set A, all targeted ARGs and int1 were detected, except for vanA. Substantial ARG concentrations persisted in the effluent. Japan and Thailand samples showed ARG patterns more similar to community-associated resistance, whereas Vietnam and the Philippines samples showed patterns potentially influenced by healthcare-associated sources. Improved treatment and targeted surveillance strategies are necessary for managing the environmental dissemination of antimicrobial resistance.