Duris Joseph W, Haack Sheridan K, Fogarty Lisa R
U.S. Geological Survey, 6520 Mercantile Way, Suite 5, Lansing, MI 48911, USA.
J Environ Qual. 2009 Jul 23;38(5):1878-86. doi: 10.2134/jeq2008.0225. Print 2009 Sep-Oct.
The relation of bacterial pathogen occurrence to fecal indicator bacteria (FIB) concentrations used for recreational water quality criteria (RWQC) is poorly understood. This study determined the occurrence of Shiga-toxin producing Escherichia coli (STEC) markers and their relation to FIB concentrations in Michigan and Indiana river water. Using 67 fecal coliform (FC) bacteria cultures from 41 river sites in multiple watersheds, we evaluated the occurrence of five STEC markers: the Escherichia coli (EC) O157 antigen and gene, and the STEC virulence genes eaeA, stx1, and stx2. Simple isolations from selected FC cultures yielded viable EC O157. By both antigen and gene assays, EC O157 was detected in a greater proportion of samples exceeding rather than meeting FC RWQC (P < 0.05), but was unrelated to EC and enterococci RWQC. The occurrence of all other STEC markers was unrelated to any FIB RWQC. The eaeA, stx2, and stx1 genes were found in 93.3, 13.3, and in 46.7% of samples meeting FC RWQC and in 91.7, 0.0, and 37.5% of samples meeting the EC RWQC. Although not statistically significant, the percentage of samples positive for each STEC marker except stx1 was lower in samples that met, as opposed to exceeded, FIB RWQC. Viable STEC were common members of the FC communities in river water throughout southern Michigan and northern Indiana, regardless of FIB RWQC. Our study indicates that further information on the occurrence of pathogens in recreational waters, and research on alternative indicators of their occurrence, may help inform water-resource management and public health decision-making.
用于娱乐用水水质标准（RWQC）的粪便指示菌（FIB）浓度与细菌病原体出现之间的关系尚不清楚。本研究确定了密歇根州和印第安纳州河水中产志贺毒素大肠杆菌（STEC）标志物的出现情况及其与FIB浓度的关系。我们使用来自多个流域41个河流站点的67份粪大肠菌群（FC）细菌培养物，评估了5种STEC标志物的出现情况：大肠杆菌（EC）O157抗原和基因，以及STEC毒力基因eaeA、stx1和stx2。从选定的FC培养物中进行简单分离得到了活的EC O157。通过抗原和基因检测，在超过而非符合FC RWQC的样本中检测到EC O157的比例更高（P < 0.05），但与EC和肠球菌RWQC无关。所有其他STEC标志物的出现与任何FIB RWQC均无关。在符合FC RWQC的样本中，eaeA、stx2和stx1基因分别在93.3%、13.3%和46.7%的样本中被发现，在符合EC RWQC的样本中分别在91.7%、0.0%和37.5%的样本中被发现。尽管无统计学意义，但除stx1外，每个STEC标志物呈阳性的样本百分比在符合而非超过FIB RWQC的样本中较低。无论FIB RWQC如何，活的STEC都是密歇根州南部和印第安纳州北部河水中FC群落的常见成员。我们的研究表明，关于娱乐用水中病原体出现情况的更多信息，以及关于其出现的替代指标的研究，可能有助于为水资源管理和公共卫生决策提供信息。
