Department of Molecular Biology, University of Gdańsk, Poland.
Microb Pathog. 2009 Dec;47(6):289-98. doi: 10.1016/j.micpath.2009.09.006. Epub 2009 Sep 15.
Shiga toxin-producing Escherichia coli (STEC) is a group of pathogenic strains responsible for bloody diarrhea and hemorrhagic colitis, with often severe complications. Shiga toxins are the main factors causing the phathogenicity of STEC. Production of these toxins depends on the presence of stx1 and stx2 genes, which are located on lambdoid prophages, and their expression is stimulated upon prophage induction. Therefore, a transition of the phage genome from the prophage state to an extrachromosomal genetic element, and its further propagation, is crucial for the pathogenic effects. However, our knowledge on specific conditions for induction of these prophages in bacteria occurring in human intestine is very limited. In this report we present results of our studies on five different phages, originally occurring in STEC strains, in comparison to bacteriophage lambda. We found that efficiencies of induction of prophages and their further development vary considerably in response to different induction agents. Moreover, efficiency of progeny phage production might be modulated by other factors, like temperature or bacterial growth rate. Therefore, it is likely that pathogenicity of different STEC strains may be significantly different under specific conditions in their natural habitats.
产志贺毒素大肠杆菌（STEC）是一组引起血性腹泻和出血性结肠炎的致病菌株，常伴有严重的并发症。志贺毒素是 STEC 致病的主要因素。这些毒素的产生取决于 stx1 和 stx2 基因的存在，这些基因位于 λ 样前噬菌体上，在前噬菌体诱导时会被刺激表达。因此，噬菌体基因组从前噬菌体状态向染色体外遗传元件的转变及其进一步传播，对其致病作用至关重要。然而，我们对人类肠道中存在的细菌中这些前噬菌体诱导的具体条件的了解非常有限。在本报告中，我们比较了最初存在于 STEC 菌株中的五种不同噬菌体的研究结果，与噬菌体 λ 相比。我们发现，前噬菌体的诱导效率及其进一步发展因不同的诱导剂而有很大差异。此外，噬菌体后代的产生效率可能受到其他因素的调节，如温度或细菌生长速度。因此，不同 STEC 菌株在其自然栖息地的特定条件下的致病性可能有很大差异。
