Dehon Emilie, Vrchovecká Stanislava, Mathieu Alban, Favre-Bonté Sabine, Wacławek Stanisław, Droit Arnaud, Vogel Timothy M, Sanchez-Cid Concepcion
Universite Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, Villeurbanne, F-7 69622, France.
CHU de Québec-Université Laval Research Center, Endocrinology and Nephrology Axis, Québec City, Québec, Canada.
Environ Microbiome. 2025 May 27;20(1):58. doi: 10.1186/s40793-025-00722-5.
Freshwater pollution with compounds used during anthropogenic activities could be a major driver of antibiotic resistance emergence and dissemination in environmental settings. Fluoroquinolones and heavy metals are two widely used aquatic pollutants that show a high stability in the environment and have well-known effects on antibiotic resistance selection. However, the impact of these compounds on antibiotic resistance maintenance in aquatic ecosystems remains unknown. In this study, we used a microcosm approach to determine the persistence of two fluoroquinolones (ciprofloxacin, ofloxacin) and two heavy metals (copper and zinc) in the Rhône river over 27 days. In addition, we established links between antibiotic and metal pollution, alone and in combination, and the composition of freshwater bacterial communities, the selection of specific members and the selection and maintenance of antibiotic and metal resistance genes (ARGs and MRGs) using a metagenomics approach.
Whereas ofloxacin was detected at higher levels in freshwater after 27 days, copper had the strongest influence on bacterial communities and antibiotic and metal resistance gene selection. In addition, heavy metal exposure selected for some ARG-harboring bacteria that contained MRGs. Our research shows a heavy metal-driven transient co-selection for fluoroquinolone resistance in an aquatic ecosystem that could be largely explained by the short-term selection of Pseudomonas subpopulations harboring both fluoroquinolone efflux pumps and copper resistance genes.
This research highlights the complexity and compound-specificity of dose-response relationships in freshwater ecosystems and provides new insights into the medium-term community structure modifications induced by overall sub-inhibitory levels of antibiotic and heavy metal pollution that may lead to the selection and maintenance of antibiotic resistance in low-impacted ecosystems exposed to multiple pollutants.
人为活动中使用的化合物造成的淡水污染可能是环境中抗生素耐药性出现和传播的主要驱动因素。氟喹诺酮类药物和重金属是两种广泛使用的水污染物，它们在环境中具有很高的稳定性，并且对抗生素耐药性选择有众所周知的影响。然而，这些化合物对水生生态系统中抗生素耐药性维持的影响仍然未知。在本研究中，我们采用微观生态系统方法来确定罗纳河中两种氟喹诺酮类药物（环丙沙星、氧氟沙星）和两种重金属（铜和锌）在27天内的持久性。此外，我们使用宏基因组学方法，建立了抗生素和金属污染单独及联合作用与淡水细菌群落组成、特定成员的选择以及抗生素和金属抗性基因（ARGs和MRGs）的选择与维持之间的联系。
27天后，氧氟沙星在淡水中的检测水平较高，而铜对细菌群落以及抗生素和金属抗性基因选择的影响最强。此外，重金属暴露选择了一些含有MRGs的携带ARG的细菌。我们的研究表明，在水生生态系统中，重金属驱动了对氟喹诺酮耐药性的短暂共选择，这在很大程度上可以通过对同时携带氟喹诺酮外排泵和铜抗性基因的假单胞菌亚群的短期选择来解释。
本研究突出了淡水生态系统中剂量-反应关系的复杂性和化合物特异性，并为抗生素和重金属总体亚抑制水平引起的中期群落结构变化提供了新的见解，这些变化可能导致在受多种污染物影响较小的生态系统中抗生素耐药性的选择和维持。
