College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China.
Environ Res. 2024 Oct 15;259:119554. doi: 10.1016/j.envres.2024.119554. Epub 2024 Jul 2.
Hospital wastewaters (HWWs) serve as critical reservoirs for disseminating antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB). However, the dynamics and noteworthy shifts of ARGs and their associated pathogenicity, mobility, and resistome risks during HWWs treatment processes remain poorly understood. Utilizing metagenomic sequencing and assembly, we identified 817 ARG subtypes conferring resistance to 20 classes of antibiotics across 18 HWW samples from influent to effluent. Genes encoding resistance to multidrug, aminoglycoside and beta_lactam were the most prevalent ARG types, reflecting patterns observed in clinical settings. On-site treatment efforts decreased the relative abundance of ARGs by 77.4% from influent to secondary sedimentation, whereas chlorine disinfection significantly increased their abundance in the final effluent. Deterministic processes primarily drove the taxonomic assembly, with Proteobacteria being the most abundant phylum and serving as the primary host for 15 ARG types. Contig-based analysis further revealed 114 pathogenic ARB, with Escherichia coli, Pseudomonas alcaligenes, and Pseudomonas aeruginosa exhibiting multidrug-resistant. The contributions of host bacteria and pathogenic ARB varied throughout wastewater treatment. In addition, 7.10%-31.0 % ARGs were flanked by mobile genetic elements (MGEs), predominantly mediated by transposase (74.1%). Notably, tnpA exhibited the highest potential for ARG dissemination, frequently co-occurring with beta-lactam resistance genes (35.2%). Considering ARG profiles, pathogenic hosts, and transferability, raw influent exhibited the highest antibiotic resistome risk index (ARRI), followed by the final effluent. Chlorine disinfection exacerbated resistome risks by inducing potential pathogenic ARB and mobile ARGs, posing threats to the receiving environment. This study delineates ARG occurrence patterns, highlights mechanisms of ARG carriage and horizontal gene transfer, and provides insights for assessing resistance risks and prioritizing interventions in clinical settings.
医院废水（HWW）是传播抗生素耐药基因（ARGs）和抗生素耐药菌（ARB）的重要储库。然而，HWW 处理过程中 ARGs 的动态变化及其相关的致病性、可移动性和耐药组风险尚不清楚。利用宏基因组测序和组装，我们从 18 个 HWW 样本的进水到出水，共鉴定出 817 种不同抗生素耐药表型的 ARG 亚型，涵盖了 20 类抗生素。编码对多药、氨基糖苷类和β-内酰胺类药物耐药的基因是最常见的 ARG 类型，反映了临床环境中的模式。现场处理措施使进水到二级沉淀的 ARG 相对丰度降低了 77.4%，而氯消毒则显著增加了最终出水的 ARG 丰度。确定性过程主要驱动了分类组装，其中变形菌门是最丰富的门，是 15 种 ARG 类型的主要宿主。基于基因序列的分析进一步揭示了 114 种致病性 ARB，其中大肠杆菌、产碱假单胞菌和铜绿假单胞菌表现出多药耐药性。宿主细菌和致病性 ARB 在整个废水处理过程中的贡献不同。此外，7.10%-31.0%的 ARG 侧翼有移动遗传元件（MGEs），主要由转座酶介导（74.1%）。值得注意的是，tnpA 具有最强的 ARG 传播潜力，经常与β-内酰胺类耐药基因共同出现（35.2%）。考虑到 ARG 谱、致病宿主和可转移性，原水进水表现出最高的抗生素耐药组风险指数（ARRI），其次是最终出水。氯消毒通过诱导潜在的致病性 ARB 和移动 ARGs 加剧了耐药组的风险，对受纳环境构成威胁。本研究描述了 ARG 的发生模式，强调了 ARG 携带和水平基因转移的机制，并为评估临床环境中的耐药风险和确定干预措施提供了依据。
