Perfluorobutane sulfonate reshapes microbial metabolism and enhances antibiotic resistance and pathogen dissemination...

As the use of short-chain per- and polyfluoroalkyl substances, particularly perfluorobutane sulfonate (PFBS), continues to increase, their accumulation in wastewater treatment plants (WWTPs) and the associated ecological risks have attracted growing attention. Nevertheless, the impacts of PFBS on the anaerobic ammonium oxidation (anammox) process, as well as its role in the dissemination of antibiotic resistance genes (ARGs) and the proliferation of pathogens, remain poorly understood. In this study, metagenomic analysis combined with multidimensional data integration was employed to systematically investigate the effects of PFBS exposure on anammox performance, microbial metabolism, and ARG dynamics. The results revealed that PFBS exposure significantly deteriorated nitrogen removal, leading to a 10.16% reduction in total nitrogen removal efficiency. Carbon metabolism was inhibited, whereas microbial communities adapted by enhancing antioxidant capacity and electron transport activity. The relative abundance of key anammox functional genes (hzs and hdh) decreased by 54.65% and 57.32%, respectively. Molecular docking analysis demonstrated a strong binding affinity between PFBS and hydrazine dehydrogenase (-8 kcal/mol), suggesting potential interactions. Moreover, PFBS exhibited notable interactions with denitrification-related enzymes, suggesting potential perturbations to denitrification pathways. Additionally, PFBS facilitated the enrichment of ARG and mobile genetic elements (MGE), thereby increasing the potential for MGE-mediated ARG dissemination. PFBS enriched potential pathogenic microorganisms and strengthened their associations with ARGs. Collectively, these findings demonstrate that PFBS exposure compromises anammox performance while simultaneously elevating antimicrobial resistance dissemination and pathogen-associated risks, highlighting its ecological implications in WWTPs.