Department of Bacteriology, Food Research Institute, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA.
Curr Microbiol. 2012 Dec;65(6):660-5. doi: 10.1007/s00284-012-0210-8. Epub 2012 Aug 25.
The contribution of RecA, Dps, and RpoS to survival of Escherichia coli O157:H7 during desiccation and osmotic stress was determined in Luria-Bertani broth with 12 % NaCl (LB-12) at 30 and 37 °C, on filter disks at 23 and 30 °C, and in sterile bovine feces at 30 °C. RecA did not significantly contribute to survival in any condition or temperature. The contribution of Dps to survival was only significant in LB-12 at 37 °C. RpoS was necessary for survival during desiccation and osmotic stress, and survival of the RpoS mutant was significantly less than the parent in all conditions and temperatures. The RpoS mutant survived up to 21 days in bovine feces, <4 days on filter disks, and >8 and <4 days in LB-12 at 30 and 37 °C, respectively. The parent, ΔrecA, dps, and dps/ΔrecA mutant strains survived >8 days in LB-12, >28 days on filter disks, and >28 days in bovine feces. Increased incubation temperatures were associated with decreased survival. E. coli O157:H7 can persist in desiccating and osmotically challenging environments, especially sterile feces, for an extended period time.
RecA、Dps 和 RpoS 对大肠杆菌 O157:H7 在 30 和 37°C 的 LB-12（含 12%NaCl 的 Luria-Bertani 肉汤）、23 和 30°C 的滤膜上以及 30°C 的无菌牛粪便中的干燥和渗透压胁迫条件下的生存能力的贡献进行了测定。RecA 在任何条件或温度下都没有显著影响生存能力。Dps 对生存能力的贡献仅在 37°C 的 LB-12 中显著。RpoS 是干燥和渗透压胁迫条件下生存所必需的，RpoS 突变体的生存能力在所有条件和温度下均显著低于亲本。RpoS 突变体在牛粪便中可存活长达 21 天，在滤膜上存活不到 4 天，在 30 和 37°C 的 LB-12 中分别存活超过 8 天和不到 4 天。亲本、ΔrecA、dps 和 dps/ΔrecA 突变株在 LB-12 中存活超过 8 天，在滤膜上存活超过 28 天，在牛粪便中存活超过 28 天。孵育温度升高与生存能力降低有关。大肠杆菌 O157:H7 可以在干燥和渗透压挑战的环境中，特别是在无菌粪便中，长时间存活。
