USDA Agriculture Research Service, J Phil Campbell, Sr Natural Resource Conservation Center, Watkinsville, Georgia 30677, USA.
Environ Sci Technol. 2011 Mar 1;45(5):1853-8. doi: 10.1021/es1032019. Epub 2011 Feb 9.
In situ and in vitro experiments were performed to assess the effects of solar radiation and predation by indigenous microflora on the relative die-off rates of a toxigenic strain of Escherichia coli O157:H7, commensal E. coli, and fecal enterococci in surface waters from ponds in agricultural watersheds. The objective of these experiments was to discern a mechanism of persistence of E. coli O157:H7 in surface waters compared to fecal indicator bacteria. Results of these experiments indicated that E. coli and fecal enterococci were affected by both insolation and apparent predation; whereas E. coli O157:H7 appeared to be resistant to both of these environmental stressors. The number of days to reach 99% die-off (T(99)-values) for E. coli O157:H7 was significantly greater than that for the indicator bacteria. The capacity to prolong die-off may be connected to the apparent persistence of E. coli O157:H7 in surface waters.
进行了原位和体外实验，以评估太阳辐射和本地微生物区系捕食对农业流域池塘地表水中毒力大肠杆菌 O157:H7、共生大肠杆菌和粪便肠球菌相对死亡率的影响。这些实验的目的是为了与粪便指示菌相比，找出大肠杆菌 O157:H7 在地表水系统中持续存在的机制。这些实验的结果表明，光照和明显的捕食都会影响大肠杆菌和粪便肠球菌；而大肠杆菌 O157:H7 似乎对这两种环境胁迫因子具有抗性。达到 99%死亡率所需的天数（T(99)-值）大肠杆菌 O157:H7 明显长于指示菌。延长死亡率的能力可能与大肠杆菌 O157:H7 在地表水系统中的明显持续存在有关。
