Research and Production Center "MicroMir", LLC, Moscow, Russia.
Department of Virology, Lomonosov Moscow State University, Moscow, Russia.
Virol J. 2021 Jan 6;18(1):9. doi: 10.1186/s12985-020-01485-w.
Nowadays, hundreds of thousands of deaths per year are caused by antibiotic resistant nosocomial infections and the prognosis for future years is much worse, as evidenced by modern research. Bacteria of the Klebsiella genus are one of the main pathogens that cause nosocomial infections. Among the many antimicrobials offered to replace or supplement traditional antibiotics, bacteriophages are promising candidates.
This article presents microbiological, physicochemical and genomic characterization of 4 virulent bacteriophages belonging to Siphoviridae, Myoviridae and Podoviridae families. Phages were studied by electron microscopy; their host range, lytic activity, adsorption rate, burst size, latent period, frequency of phage-resistant forms generation, lysis dynamics and sensitivity of phage particles to temperature and pH were identified; genomes of all 4 bacteriophages were studied by restriction digestion and complete genome sequence.
Studied phages showed wide host range and high stability at different temperature and pH values. In contrast with single phages, a cocktail of bacteriophages lysed all studied bacterial strains, moreover, no cases of the emergence of phage-resistant bacterial colonies were detected. Genomic data proved that isolated viruses do not carry antibiotic resistance, virulence or lysogenic genes. Three out of four bacteriophages encode polysaccharide depolymerases, which are involved in the degradation of biofilms and capsules.
The bacteriophages studied in this work are promising for further in vivo studies and might be used in phage therapy as part of a complex therapeutic and prophylactic phage preparation. The conducted studies showed that the complex preparation is more effective than individual phages. The use of the complex phage cocktail allows to extend the lytic spectrum, and significantly reduces the possibility of phage-resistant forms generation.
如今，每年有数十万人因抗生素耐药性医院感染而死亡，未来几年的情况更糟，现代研究也证明了这一点。克雷伯氏菌属的细菌是引起医院感染的主要病原体之一。在提供的许多替代或补充传统抗生素的抗菌药物中，噬菌体是很有前途的候选药物。
本文介绍了属于长尾噬菌体科、肌尾噬菌体科和短尾噬菌体科的 4 种烈性噬菌体的微生物学、物理化学和基因组特征。通过电子显微镜研究噬菌体；鉴定了它们的宿主范围、裂解活性、吸附率、爆发大小、潜伏期、噬菌体抗性形式产生的频率、裂解动力学以及噬菌体颗粒对温度和 pH 的敏感性；通过限制性消化和完整基因组序列研究了所有 4 种噬菌体的基因组。
研究的噬菌体表现出广泛的宿主范围和在不同温度和 pH 值下的高稳定性。与单一噬菌体相比，噬菌体鸡尾酒可裂解所有研究的细菌菌株，而且没有检测到噬菌体抗性细菌菌落的出现。基因组数据表明，分离的病毒不携带抗生素耐药性、毒力或溶原性基因。四种噬菌体中有三种编码多糖降解酶，参与生物膜和胶囊的降解。
本研究中研究的噬菌体具有进一步体内研究的潜力，并可能作为复杂治疗和预防噬菌体制剂的一部分用于噬菌体治疗。进行的研究表明，复合制剂比单一噬菌体更有效。使用复合噬菌体鸡尾酒可以扩大裂解谱，并显著降低噬菌体抗性形式产生的可能性。
