Center for General Education, Cheng-Shiu University, Kaohsiung, Taiwan, Republic of China.
Environ Sci Pollut Res Int. 2011 Aug;19(7):2776-83. doi: 10.1007/s11356-012-0777-4. Epub 2012 Feb 12.
The high incidences of waterborne diseases are frequently associated with diarrheagenic Escherichia coli (DEC). DEC may pose a health risk to people who contact surface water for recreation or domestic use. However, there is no published report on the monitoring of DEC in drinking water sources in Taiwan. In this study, the occurrence of DEC genes in raw water for water treatment plants in Taiwan was investigated.
Raw water samples were taken from water treatment plants adjacent to the Kaoping River in southern Taiwan. Each water sample was treated with membrane filtration followed by DNA extraction from the concentrate and concentrate enrichment, respectively. The target genes for various DEC strains of genes were identified, including enteroaggregative E. coli (EAEC), enterohemorrhagic E. coli (EHEC), enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC), and enterotoxigenic E. coli (ETEC).
Among 55 water samples analyzed, DEC genes were detected in 16 (29.1%) samples. Strain-specific genes for EAEC, EHEC, EIEC, and EPEC were found in the percentages of 3.6%, 10.9%, 9.1%, and 9.1%, respectively. The specific gene for ETEC is not detected in the study. By looking at the presence/absence of specific genes and water sample characteristics, water temperature was found to differ significantly between samples with and without EHEC gene. In addition, pH levels differed significantly for EHEC and EPEC presence/absence genes, and turbidity was significantly different for water with and without EPEC genes.
DEC genes were detected in 29.1% of the raw water samples in the study location. The potential health threat may be increased if the treatment efficiencies are not properly maintained. Routine monitoring of DEC in drinking water sources should be considered.
食源性疾病高发与产肠毒性大肠杆菌（DEC）密切相关。DEC 可能会对接触地表水用于娱乐或家庭用途的人造成健康风险。然而，在台湾，目前还没有关于饮用水源中 DEC 监测的报道。本研究调查了台湾水处理厂原水中 DEC 基因的发生情况。
采集了台湾南部高雄河附近水处理厂的原水水样。分别用膜过滤法处理每个水样，然后分别从浓缩液和浓缩液中提取 DNA。鉴定了各种 DEC 菌株的目标基因，包括聚集性肠致病性大肠杆菌（EAEC）、肠出血性大肠杆菌（EHEC）、肠侵袭性大肠杆菌（EIEC）、肠致病性大肠杆菌（EPEC）和肠毒性大肠杆菌（ETEC）。
在分析的 55 个水样中，有 16 个（29.1%）水样中检测到 DEC 基因。在 EAEC、EHEC、EIEC 和 EPEC 中分别发现了 3.6%、10.9%、9.1%和 9.1%的菌株特异性基因。研究中未检测到 ETEC 的特异性基因。通过观察特定基因的存在/缺失和水样特征，发现水温在有和无 EHEC 基因的水样之间有显著差异。此外，EHEC 和 EPEC 存在/缺失基因的 pH 值有显著差异，而 EPEC 基因存在和缺失的水样浊度有显著差异。
在所研究的地点，29.1%的原水水样中检测到 DEC 基因。如果处理效率得不到适当维护，潜在的健康威胁可能会增加。应考虑对饮用水源中的 DEC 进行常规监测。
