Department of Biological Sciences, Kent State University, Kent, OH 44242, United States of America.
Department of Biological Sciences, Kent State University at Tuscarawas, New Philadelphia, OH 44663, United States of America.
Sci Total Environ. 2019 Oct 20;688:437-449. doi: 10.1016/j.scitotenv.2019.06.053. Epub 2019 Jun 7.
Urban stream biofilms are potential hotspots for resistomes and antibiotic resistance genes (ARGs). Biofilm communities that harbor resistance genes may be influenced by contaminant input (e.g., metals and antibiotics) from urban drainage (i.e., Wastewater Treatment Plant effluent and stormwater runoff); understanding the ecology of these communities and their resistome is needed. Given the potential importance of the co-occurrence of ARGs and metal resistance genes (MRGs), we investigated the spatial and temporal distribution of three ARGs (tetracycline [tetW] and sulfonamides [sulI and sulII]), four MRGs (lead [pbrT], copper [copA], and cadmium/cobalt/zinc [czcA and czcC]) via quantitative PCR and biofilm bacterial community composition via MiSeq 16S sequencing at four time points along an urbanization gradient (i.e., developed, agriculture, and forested sites) in a stream's watershed. Our results revealed that ARG and MRG abundances were significantly affected by land use-time interaction, with greater resistance abundances occurring in more urban locations during particular times of the year. It was also observed that changes in ARG and MRG profiles were influenced by differences in community composition among land use types, and that these differences were in response to changes in stream physicochemical parameters (pH, redox, temperature, nutrient availability, and metal concentration) that were driven by sub-watershed land use. Moreover, the dynamics between ARGs and MRGs within these communities correlated strongly and positively with one another. Taken altogether, our results demonstrate that changes in environmental properties due to human activity may drive the ARG-MRG profiles of biofilm communities by modulating community structure over time and space.
城市溪流生物膜是抗性基因(resistomes)和抗生素抗性基因(ARGs)的潜在热点。携带抗性基因的生物膜群落可能会受到城市排水系统（即污水处理厂出水和雨水径流）中污染物输入（如金属和抗生素）的影响；需要了解这些群落及其抗性组的生态情况。鉴于 ARGs 和金属抗性基因 (MRGs) 同时存在的潜在重要性，我们通过定量 PCR 调查了三个 ARGs（四环素 [tetW] 和磺胺类 [sulI 和 sulII]）、四个 MRGs（铅 [pbrT]、铜 [copA]、镉/钴/锌 [czcA 和 czcC]）的时空分布，以及通过 MiSeq 16S 测序分析了溪流流域沿城市化梯度（即开发、农业和森林地区）四个时间点的生物膜细菌群落组成。我们的结果表明，ARG 和 MRG 的丰度受到土地利用时间相互作用的显著影响，在一年中的特定时间，在更城市化的地区，抗性丰度更高。还观察到，ARG 和 MRG 谱的变化受到不同土地利用类型之间群落组成差异的影响，而这些差异是对由子流域土地利用驱动的溪流理化参数（pH、氧化还原、温度、养分供应和金属浓度）变化的响应。此外，这些群落中 ARGs 和 MRGs 之间的动态关系彼此强烈正相关。总的来说，我们的结果表明，由于人类活动导致的环境特性变化可能会通过随时间和空间改变群落结构来驱动生物膜群落的 ARG-MRG 谱。
