Genotypic Diversity of Escherichia coli in the Water and Soil of Tropical Watersheds in Hawaii
Genotypic Diversity of Escherichia coli in the Water and Soil of Tropical Watersheds in Hawaii
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DOI：
10.1128/aem.02140-10
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发表时间：
2011-06-01
影响因子：
4.4
通讯作者：
Yan, Tao
中科院分区：
文献类型：
--
作者：
Goto, Dustin K.;Yan, Tao
在夏威夷的热带土壤中经常检测到高水平的大肠杆菌，这是大肠杆菌对水体的重要环境来源。本研究系统地检测了夏威夷几个流域的水和土壤中分离的大肠杆菌，观察到较高的整体基因型多样性（35.5%的独特基因型）。在Manoa流域，在不同采样点之间，水中和土壤中所观察到的大肠杆菌基因型中只有不到9.3%和6.6%是相同的，这表明该流域缺乏优势的粪便来源。土壤中大肠杆菌基因型的高时间变异性也被观察到，这表明一个动态的大肠杆菌种群与热带土壤中经常观察到的高浓度相对应。当比较从相同采样事件中检测到的大肠杆菌基因型时，在大多数比较中（73.5%）观察到土壤和水样之间有限的共享。然而，一些比较报告了土壤和水之间高达33.3%的大肠杆菌基因型重叠，说明在有利的环境条件下土壤-水相互作用的潜力。此外，水和土壤中大肠杆菌的基因型积累曲线表明，Manoa流域的采样工作不能耗尽整体基因型多样性。比较来自夏威夷瓦胡岛其他流域的大肠杆菌基因型，根据采样地点没有发现明显的分组。本研究的结果表明，在热带流域使用大肠杆菌作为粪便指示细菌的复杂性，并强调在水质监测中区分大肠杆菌的环境来源和粪便来源的必要性。
High levels of Escherichia coli were frequently detected in tropical soils in Hawaii, which present important environmental sources of E. coli to water bodies. This study systematically examined E. coli isolates from water and soil of several watersheds in Hawaii and observed high overall genotypic diversity (35.5% unique genotypes). In the Manoa watershed, fewer than 9.3% of the observed E. coli genotypes in water and 6.6% in soil were shared between different sampling sites, suggesting the lack of dominant fecal sources in the watershed. High temporal variability of E. coli genotypes in soil was also observed, which suggests a dynamic E. coli population corresponding with the frequently observed high concentrations in tropical soils. When E. coli genotypes detected from the same sampling events were compared, limited sharing between the soil and water samples was observed in the majority of comparisons (73.5%). However, several comparisons reported up to 33.3% overlap of E. coli genotypes between soil and water, illustrating the potential for soil-water interactions under favorable environmental conditions. In addition, genotype accumulation curves for E. coli from water and soil indicated that the sampling efforts in the Manoa watershed could not exhaust the overall genotypic diversity. Comparisons of E. coli genotypes from other watersheds on Oahu, Hawaii, identified no apparent grouping according to sampling locations. The results of the present study demonstrate the complexity of using E. coli as a fecal indicator bacterium in tropical watersheds and highlight the need to differentiate environmental sources of E. coli from fecal sources in water quality monitoring.