Bolster C H, Haznedaroglu B Z, Walker S L
U.S. Dep. of Agriculture - Agricultural Research Service, 230 Bennett Ln., Bowling Green, KY 42104, USA.
J Environ Qual. 2009 Feb 6;38(2):465-72. doi: 10.2134/jeq2008.0137. Print 2009 Mar-Apr.
Escherichia coli is a commonly used indicator organism for detecting the presence of fecal-borne pathogenic microorganisms in water supplies. The importance of E. coli as an indicator organism has led to numerous studies looking at cell properties and transport behavior of this microorganism. In many of these studies, however, only a single strain of E. coli was used even though research has shown that significant genetic variability exists among different strains of E. coli. If this genetic diversity results in differences in cell properties that affect transport, different strains of E. coli may exhibit different rates of transport in the environment. Therefore, the objectives of our study were to investigate the variability in surface characteristics and transport behavior of E. coli isolates obtained from six different sources: beef cattle, dairy cattle, horse, human, poultry, and wildlife. Cell properties such as electrophoretic mobility, cell size and shape, hydrophobicity, charge density, and extracellular polymeric substance composition were measured for each isolate. In addition, the transport behavior of each isolate was assessed by measuring transport through 10-cm packed beds of clean quartz sand. Our results show a large diversity in cell properties and transport behavior for the different E. coli isolates. This diversity in transport behavior must be taken into account when making assessments of the suitability of using E. coli as an indicator organism for specific pathogenic microorganisms in groundwater environments as well as modeling the movement of E. coli in the subsurface.
大肠杆菌是用于检测供水系统中粪便传播致病微生物存在情况的常用指示生物。大肠杆菌作为指示生物的重要性引发了众多关于该微生物细胞特性和迁移行为的研究。然而，在许多此类研究中，即便研究表明不同菌株的大肠杆菌存在显著的遗传变异性，但仍仅使用单一菌株的大肠杆菌。如果这种遗传多样性导致影响迁移的细胞特性存在差异，那么不同菌株的大肠杆菌在环境中的迁移速率可能会有所不同。因此，我们研究的目的是调查从六个不同来源获得的大肠杆菌分离株的表面特性和迁移行为的变异性，这六个来源分别是肉牛、奶牛、马、人类、家禽和野生动物。对每个分离株测量了细胞特性，如电泳迁移率、细胞大小和形状、疏水性、电荷密度以及胞外聚合物组成。此外，通过测量每个分离株在10厘米厚的清洁石英砂填充床中的迁移情况来评估其迁移行为。我们的结果表明，不同的大肠杆菌分离株在细胞特性和迁移行为方面存在很大差异。在评估将大肠杆菌用作地下水环境中特定致病微生物的指示生物的适用性以及模拟大肠杆菌在地下的移动时，必须考虑到这种迁移行为的多样性。
