University of Warwick, School of Life Sciences, Coventry, UK.
University of Warwick, Warwick Medical School, Coventry, UK.
Water Res. 2021 Aug 1;201:117382. doi: 10.1016/j.watres.2021.117382. Epub 2021 Jun 24.
The continued emergence of bacterial pathogens presenting antimicrobial resistance is widely recognised as a global health threat and recent attention focused on potential environmental reservoirs of antibiotic resistance genes (ARGs). Freshwater environments such as rivers represent a potential hotspot for ARGs and antibiotic resistant bacteria as they are receiving systems for effluent discharges from wastewater treatment plants (WWTPs). Effluent also contains low levels of different antimicrobials including antibiotics and biocides. Sulfonamides are antibacterial chemicals widely used in clinical, veterinary and agricultural settings and are frequently detected in sewage sludge and manure in addition to riverine ecosystems. The impact of such exposure on ARG prevalence and diversity is unknown, so the aim of this study was to investigate the release of a sub-lethal concentration of the sulfonamide compound sulfamethoxazole (SMX) on the river bacterial microbiome using a flume system. This system was a semi-natural in vitro flume using river water (30 L) and sediment (6 kg) with circulation to mimic river flow. A combination of 'omics' approaches were conducted to study the impact of SMX exposure on the microbiomes within the flumes. Metagenomic analysis showed that the addition of low concentrations of SMX (<4 μg L) had a limited effect on the bacterial resistome in the water fraction only, with no impact observed in the sediment. Metaproteomics did not show differences in ARGs expression with SMX exposure in water. Overall, the river bacterial community was resilient to short term exposure to sub-lethal concentrations of SMX which mimics the exposure such communities experience downstream of WWTPs throughout the year.
细菌病原体对抗生素的耐药性持续出现，被广泛认为是全球健康威胁，最近人们关注的焦点是抗生素耐药基因（ARGs）的潜在环境储库。河流等淡水环境是 ARGs 和耐药细菌的潜在热点，因为它们是污水处理厂（WWTP）排放废水的接收系统。废水中还含有低浓度的不同抗生素，包括抗生素和杀生物剂。磺胺类药物是一种广泛用于临床、兽医和农业环境的抗菌化学物质，除了河流生态系统外，在污水污泥和粪便中也经常被检测到。这种暴露对 ARG 流行率和多样性的影响尚不清楚，因此本研究的目的是使用水槽系统研究亚致死浓度的磺胺类化合物磺胺甲恶唑（SMX）对河流细菌微生物组的释放。该系统是一个半自然的体外水槽系统，使用河水（30 L）和沉积物（6 公斤）进行循环，以模拟河流流动。采用“组学”方法组合来研究 SMX 暴露对水槽内微生物组的影响。宏基因组分析表明，仅在水相中添加低浓度的 SMX（<4 μg L）对细菌耐药组的影响有限，在沉积物中未观察到影响。在水中，SMX 暴露对 ARG 表达没有差异。总体而言，河流细菌群落对短期暴露于亚致死浓度的 SMX 具有很强的抵抗力，这种暴露类似于 WWTP 全年下游的此类群落所经历的暴露。
