Bacterial resistome in different stages of wastewater treatment plant is highly impacted by the abundance of the Pseudomonadota community

Abstract

Wastewater treatment plants (WWTPs) are significant sources of antimicrobial resistance (AMR). We studied bacterial communities and antibiotic-resistance genes (ARGs) in different stages of a WWTP in the UAE. We found high levels of extended-spectrum beta-lactamase bacteria in the returned activated sludge (RAS) stage, including Escherichia coli and Aeromonas sobria, resistant to ESBL, ampicillin, and fosfomycin. Bacterial richness was highest in the primary effluent (PE) stage, with distinct community structures influenced by environmental factors. Pseudomonadota dominated across all stages, with Bacteroidota and Bacillota in PE, and Actinomycetota and Pseudomonadota in AS and RAS. Acidovorax sp. showed strong connections with ARGs in PE and RAS, while Delftia acidovorans had the most associations with ARGs in AS. These findings underscore the role of WWTP stages in shaping bacterial communities and ARG abundance, highlighting the potential of certain bacteria in AMR development and dissemination.