Winogradsky Institute of Microbiology, RC Biotechnology RAS, Prospekt 60-letiya Oktyabrya 7 bld. 2, Moscow, Russia, 117312.
Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology, Moscow, Russia.
Sci Rep. 2021 Feb 4;11(1):3035. doi: 10.1038/s41598-021-82422-x.
Acquisition of new prophages that are able to increase the bacterial fitness by the lysogenic conversion is believed to be an important strategy of bacterial adaptation to the changing environment. However, in contrast to the factors determining the range of bacteriophage lytic activity, little is known about the factors that define the lysogenization host range. Bacteriophage phi24B is the paradigmal model of Stx-converting phages, encoding the toxins of the Shiga-toxigenic E. coli (STEC). This virus has been shown to lysogenize a wide range of E. coli strains that is much broader than the range of the strains supporting its lytic growth. Therefore, phages produced by the STEC population colonizing the small or large intestine are potentially able to lysogenize symbiotic E. coli in the hindgut, and these secondary lysogens may contribute to the overall patient toxic load and to lead to the emergence of new pathogenic STEC strains. We demonstrate, however, that O antigen effectively limit the lysogenization of the wild E. coli strains by phi24B phage. The lysogens are formed from the spontaneous rough mutants and therefore have increased sensitivity to other bacteriophages and to the bactericidal activity of the serum if compared to their respective parental strains.
通过溶原性转换获得能够提高细菌适应性的新噬菌体，被认为是细菌适应不断变化的环境的重要策略。然而，与决定噬菌体裂解活性范围的因素相比，定义溶原化宿主范围的因素知之甚少。噬菌体 phi24B 是 Stx 转化噬菌体的典范模型，编码志贺毒素的产毒大肠杆菌 (STEC)。该病毒已被证明可以溶原化广泛的大肠杆菌菌株，其溶原化范围比支持其裂解生长的菌株范围要宽得多。因此，定植于小肠或大肠的 STEC 群体产生的噬菌体有可能溶原化后肠中的共生大肠杆菌，这些次级溶原菌可能会导致患者的整体毒性负荷增加，并导致新的致病性 STEC 菌株的出现。然而，我们证明，O 抗原有效地限制了 phi24B 噬菌体对野生大肠杆菌菌株的溶原化。溶原菌是由自发的粗糙突变体形成的，因此与各自的亲代菌株相比，它们对其他噬菌体和血清的杀菌活性更敏感。
