Kajsík Michal, Bugala Juraj, Kadličeková Veronika, Szemes Tomáš, Turňa Ján, Drahovská Hana
Comenius University Science Park, Ilkovičova 8, 841 04, Bratislava, Slovakia.
Department of Molecular Biology, Comenius University Faculty of Natural Sciences, PRIF UK, Mlynská dolina, Ilkovičova 6, 842 15, Bratislava 4, Slovakia.
Arch Virol. 2019 May;164(5):1383-1391. doi: 10.1007/s00705-019-04202-3. Epub 2019 Mar 18.
Cronobacter spp. are opportunistic pathogenic bacteria responsible for severe infections in neonates. Powdered infant formula has been confirmed to be the source of infection in some cases. Bacteriophages offer a safe means for eliminating this pathogen. In the present study, we characterized two closely related Cronobacter-specific bacteriophages of the proposed genus "GAP227virus". The phages Dev-CD-23823 and Dev-CT57 possessed broad host specificity, as they infected 88% and 80% of the Cronobacter strains tested. Genome sequence comparisons of phages Dev-CD-23823 and Dev-CT57 showed different levels of similarity to the prototype GAP227 phage. The Dev-CT57 phage was highly similar, whereas the Dev-CD-23823 phage showed only 75% sequence identity. A phylogenic tree based on the RNA polymerase (RNAP) gene from selected representatives of the subfamily Autographivirinae confirmed the grouping of Dev-CD-23823, Dev-CT57 and GAP227 in one cluster together with phages PP2, Phi80-18 and PhiR8-01. A common conserved motif was also detected in the RNAP promoters of these phages. The functional activity of these RNAP promoters was confirmed experimentally using a promoter probe vector, and a phage-specific signal was observed; however, some cross-specificity of Dev-CD-23823 and Dev-CT57 promoters was also detected. These results will contribute to our understanding of the biology and evolution of Autographivirinae phages.
阪崎肠杆菌属是导致新生儿严重感染的机会致病菌。在某些情况下，婴儿配方奶粉已被确认为感染源。噬菌体为消除这种病原体提供了一种安全的方法。在本研究中，我们对拟命名为“GAP227病毒属”的两种密切相关的阪崎肠杆菌特异性噬菌体进行了特性分析。噬菌体Dev-CD-23823和Dev-CT57具有广泛的宿主特异性，因为它们分别感染了88%和80%的测试阪崎肠杆菌菌株。噬菌体Dev-CD-23823和Dev-CT57的基因组序列比较显示，它们与原型GAP227噬菌体的相似程度不同。Dev-CT57噬菌体高度相似，而Dev-CD-23823噬菌体仅显示75%的序列同一性。基于自剪切噬菌体亚科选定代表的RNA聚合酶（RNAP）基因构建的系统发育树证实，Dev-CD-23823、Dev-CT57和GAP227与噬菌体PP2、Phi80-18和PhiR8-01一起聚集在一个簇中。在这些噬菌体的RNAP启动子中也检测到一个共同的保守基序。使用启动子探针载体通过实验证实了这些RNAP启动子的功能活性，并观察到了噬菌体特异性信号；然而，也检测到了Dev-CD-23823和Dev-CT57启动子的一些交叉特异性。这些结果将有助于我们理解自剪切噬菌体亚科噬菌体的生物学特性和进化。
