Work

Deciphering the mobility, pathogenic hosts, and co-selection of antibiotic resistance genes in untreated wastewater from three different hospitals

Year: 2025

Type: article

Abstract: Antibiotic resistance genes (ARGs) in hospital wastewater pose significant environmental and public health risks, yet the co-selection mechanisms involving metal/biocide resistance genes (MRGs/BRGs) and the role of mobile genetic elements (MGEs) remain poorly characterized. This study aimed to comprehensively assess the abundance, mobility, pathogenic hosts, and co-selection patterns of ARGs, MRGs, and BRGs in untreated wastewater from three types of hospitals. Untreated wastewater samples from nine sources across three hospital types (general, traditional Chinese medicine, and dental) were analyzed using metagenomic sequencing and assembly. ARGs, MRGs, and BRGs were identified via the SARG and BacMet databases. ARG hosts, mobility, and MGE co-occurrence were analyzed using PlasFlow and MOB-suite, with risk levels evaluated alongside pathogenic bacteria databases. A total of 1911 ARGs (222 subtypes), 1662 MRGs (167 subtypes), and 916 BRGs (139 subtypes) were detected. Tetracycline, multidrug, and β-lactam resistance genes were predominant, with 46.43 % of ARGs being plasmid-associated. Key pathogens including Klebsiella pneumoniae and Enterococcus spp. harbored high-risk ARGs such as KPC-2 and NDM-1 . Notably, 76.2 % of ARGs in traditional Chinese medicine hospital wastewater were classified as high-risk. Significant co-occurrence of ARGs with MGEs (e.g., DDE recombinases) and MRGs/BRGs was observed, underscoring the role of horizontal gene transfer and co-selection. Untreated hospital wastewater represents a significant reservoir of ARGs, with risks exacerbated by pathogenic hosts, MGE-mediated HGT, and metal/biocide co-selection. These findings underscore the urgent need for optimized wastewater treatment strategies to curb the spread of antibiotic resistance and inform future intervention efforts. • Untreated hospital wastewater harbors diverse and abundant ARGs, with 76.2 % classified as high-risk in traditional Chinese medicine hospital (TCMH) effluent. • Key pathogens like Klebsiella pneumoniae and Enterococcus spp. carry high-risk carbapenemase genes (KPC-2, NDM-1), posing significant public health threats. • Metagenomic assembly provides direct genetic evidence of ARG co-localization with MRGs/BRGs and MGEs on shared contigs. • Co-selection mechanisms (co-resistance, cross-resistance, co-regulation) are prevalent, driven by metals/biocides and facilitated by MGEs like plasmids, integrons, and phages. • Hospital type significantly influences resistome profiles, with TCMH wastewater showing the highest ARGs/MRGs/BRGs abundance and diversity, highlighting the need for tailored treatment strategies.

Source: Infection Genetics and Evolution

DOI: 10.1016/j.meegid.2025.105840

Authors: Yanying Feng, Qiheng Yuan, Longji Wang, Yutong Kang, Meiqin Zheng, Zhenjun Li