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首页> 外文期刊>International Journal of Environmental Research and Public Health >Microbiological Evaluation of Water Quality from Urban Watersheds for Domestic Water Supply Improvement
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Microbiological Evaluation of Water Quality from Urban Watersheds for Domestic Water Supply Improvement

机译：用于改善生活用水的城市流域水质的微生物学评估

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Agricultural and urban runoffs may be major sources of pollution of water bodies and major sources of bacteria affecting the quality of drinking water. Of the different pathways by which bacterial pathogens can enter drinking water, this one has received little attention to date; that is, because soils are often considered to be near perfect filters for the transport of bacterial pathogens through the subsoil to groundwater. The goals of this study were to determine the distribution, diversity, and antimicrobial resistance of pathogenic Escherichia coli isolates from low flowing river water and sediment with inputs from different sources before water is discharged into ground water and to compare microbial contamination in water and sediment at different sampling sites. Water and sediment samples were collected from 19 locations throughout the watershed for the isolation of pathogenic E. coli. Heterotrophic plate counts and E. coli were also determined after running tertiary treated water through two tanks containing aquifer sand material. Presumptive pathogenic E. coli isolates were obtained and characterized for virulent factors and antimicrobial resistance. None of the isolates was confirmed as Shiga toxin E. coli (STEC), but as others, such as enterotoxigenic E. coli (ETEC). Pulsed field gel electrophoresis (PFGE) was used to show the diversity E. coli populations from different sources throughout the watershed. Seventy six percent of the isolates from urban sources exhibited resistance to more than one antimicrobial agent. A subsequent filtration experiment after water has gone through filtration tanks containing aquifer sand material showed that there was a 1 to 2 log reduction in E. coli in aquifer sand tank. Our data showed multiple strains of E. coli without virulence attributes, but with high distribution of resistant phenotypes. Therefore, the occurrence of E. coli with multiple resistances in the environment is a matter of great concern due to possible transfer of resistant genes from nonpathogenic to pathogenic strains that may result in increased duration and severity of morbidity.
机译：农业和城市径流可能是水体污染的主要来源，也是影响饮用水质量的主要细菌来源。在细菌病原体进入饮用水的不同途径中，迄今为止，这一途径鲜为人知。也就是说，因为通常认为土壤是细菌病原体通过底土输送到地下水的理想过滤器。这项研究的目的是确定从低流量河水和沉积物中分离到的病原性大肠杆菌的分布，多样性和抗药性，然后将水排放到地下水中之前用不同来源的投入进行比较，并比较水和沉积物中微生物的污染。不同的采样地点。从整个流域的19个地点收集了水和沉积物样本，用于分离致病性大肠杆菌。在将三次处理过的水流过两个装有含水层砂子的水箱之后，还确定了异养菌平板数和大肠杆菌。获得推定的致病性大肠杆菌分离株，并对其毒性因子和抗菌素耐药性进行了表征。没有分离物被确认为志贺毒素大肠杆菌（STEC），但也被确认为其他毒素，例如肠毒素大肠杆菌（ETEC）。脉冲场凝胶电泳（PFGE）用于显示整个流域中不同来源的大肠杆菌种群的多样性。来自城市的76％的分离株表现出对一种以上抗菌剂的抗药性。在水流过装有含水层砂子的过滤槽后的后续过滤实验表明，含水层砂槽中的大肠杆菌减少了1至2 log。我们的数据显示多种大肠杆菌菌株没有毒力属性，但耐药表型分布较高。因此，由于抗性基因可能从非致病性菌株转移到致病性菌株中，这可能导致病程延长和病情严重性增加，因此在环境中出现具有多重抗性的大肠杆菌是一个令人高度关注的问题。

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