PDF(Pubmed)
Abstract：
Freshwater environments are primary receiving systems of wastewater and effluents, which carry low concentrations of antibiotics and antimicrobial-resistant (AMR) bacteria and genes. Aquatic microbial communities are thus exposed to environmentally relevant concentrations of antibiotics (ERCA) that presumably influence the acquisition and spread of environmental AMR. Here, we analyzed ERCA exposure with and without the additional presence of municipal wastewater treatment plant effluent (W) and swine manure run-off (M) on aquatic biofilm resistomes. Microscopic analyses revealed decreased taxonomic diversity and biofilm structural integrity, while metagenomic analysis revealed an increased abundance of resistance, virulence, and mobile element-related genes at the highest ERCA exposure levels, with less notable impacts observed when solely exposed to W or M effluents. Microbial function predictions indicated increased gene abundance associated with energy and cell membrane metabolism and heavy metal resistance under ERCA conditions. In silico predictions of increased resistance mechanisms did not correlate with observed phenotypic resistance patterns when whole communities were exposed to antimicrobial susceptibility testing. This reveals important insight into the complexity of whole-community coordination of physical and genetic responses to selective pressures. Lastly, the environmental AMR risk assessment of metagenomic data revealed a higher risk score for biofilms grown at sub-MIC antibiotic conditions.
摘要：
淡水环境是废水和废水的主要接收系统，其中携带低浓度的抗生素和抗微生物药物抗性（AMR）细菌和基因。因此，水生微生物群落暴露于环境相关浓度的抗生素（ERCA），这可能会影响环境AMR的获取和传播。这里,我们分析了在有或没有额外存在城市污水处理厂废水（W）和猪粪径流（M）的情况下对水生生物膜抗性的ERCA暴露。显微分析显示生物分类多样性和生物膜结构完整性下降，而宏基因组分析显示抗性增加，毒力,和移动元素相关基因在最高的ERCA暴露水平，当仅暴露于W或M流出物时，观察到的影响不太明显。微生物功能预测表明，在ERCA条件下，与能量和细胞膜代谢以及重金属抗性相关的基因丰度增加。当整个社区暴露于抗菌药物敏感性测试时，对抗性机制增加的计算机预测与观察到的表型抗性模式无关。这揭示了对选择压力的物理和遗传反应的整个社区协调的复杂性的重要见解。最后,宏基因组数据的环境AMR风险评估显示,亚MIC抗生素条件下生长的生物膜的风险评分较高.
