Induction of Shiga toxin-converting prophage in Escherichia coli by high hydrostatic pressure
Induction of Shiga toxin-converting prophage in Escherichia coli by high hydrostatic pressure
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DOI：
10.1128/aem.71.3.1155-1162.2005
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发表时间：
2005-03-01
影响因子：
4.4
通讯作者：
Michiels, CW
中科院分区：
文献类型：
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作者：
Aertsen, A;Faster, D;Michiels, CW
由于高静水压在现代食品保存中变得越来越重要，因此需要彻底研究其对微生物的潜在影响。在这种情况下，最近已证明温和的压力（< 200 MPa）可以诱导大肠杆菌 MG1655 产生 SOS 反应。由于这种反应，我们观察到用亚致死压力处理大肠杆菌溶原菌后，lambda 前噬菌体依赖于 RecA 和 LexA 诱导。在本报告中，我们将这一观察扩展到 MG1655 中的兰氏志贺毒素 (Stx) 转化噬菌体，该噬菌体构成了产 Stx 大肠杆菌菌株 (STEC) 的重要毒力特征。能够诱导 Stx 噬菌体的压力窗口与细菌存活窗口密切相关。当对全脂牛奶进行压力处理时（众所周知，这可以促进细菌存活），在大肠杆菌 MG1655 中可以在高达 250 MPa 的压力下观察到 Stx 噬菌体诱导，在该菌株的耐压突变体中可以在高达 300 MPa 的压力下观察到 Stx 噬菌体诱导。此外，我们发现两种类型的 Stx 噬菌体的内在耐压性非常不同，其中一种类型在 20 摄氏度、高达 400 MPa 的压力处理 15 分钟后仍能相对良好地存活。有趣的是，与紫外线照射或丝裂霉素 C 处理相反，压力无法在几种天然产生 Stx 的 STEC 分离株中诱导 Stx 原噬菌体或 SOS 反应。
Since high hydrostatic pressure is becoming increasingly important in modern food preservation, its potential effects on microorganisms need to be thoroughly investigated. In this context, mild pressures (< 200 MPa) have recently been shown to induce an SOS response in Escherichia coli MG1655. Due to this response, we observed a RecA- and LexA-dependent induction of lambda prophage upon treating E. coli lysogens with sublethal pressures. In this report, we extend this observation to lambdoid Shiga toxin (Stx)-converting bacteriophages in MG1655, which constitute an important virulence trait in Stx-producing E. coli strains (STEC). The window of pressures capable of inducing Stx phages correlated well with the window of bacterial survival. When pressure treatments were conducted in whole milk, which is known to promote bacterial survival, Stx phage induction could be observed at up to 250 MPa in E. coli MG1655 and at up to 300 MPa in a pressure-resistant mutant of this strain. In addition, we found that the intrinsic pressure resistance of two types of Stx phages was very different, with one type surviving relatively well treatments of up to 400 MPa for 15 min at 20 degrees C. Interestingly, and in contrast to UV irradiation or mitomycin C treatment, pressure was not able to induce Stx prophage or an SOS response in several natural Stx-producing STEC isolates.