一株金黄色葡萄球菌噬菌体的裂解谱特异性和分子分类研究

Host range and molecular classification of a Staphylococcus aureus bacteriophage

摘要:

[目的] 从医院污水中分离金黄色葡萄球菌噬菌体，观察其形态，确证裂解谱特征并研究生物学和基因学特性，为噬菌体的临床应用奠定实验基础。[方法] 将金黄色葡萄球菌ATCC25923作为宿主菌，采用双层琼脂平板法从医院污水中分离纯化噬菌体，电镜下观察形态并测定其最佳感染复数、一步生长曲线及裂解谱；全基因组测序并进行基因结构分析和功能注释。[结果] 从4份医院污水中共分离到1株金黄色葡萄球菌噬菌体（命名为vB_SauH_SAP1），仅裂解10株临床分离的葡萄球菌属受试菌（共计37株），其余74株其他种属菌株不能被裂解；透射电镜观察具有正20面体头部和收缩性尾部，属于肌尾噬菌体；其最佳感染复数为0.1，潜伏期10 min，裂解期为20 min。vB_SauH_SAP1基因组全长143375 bp，G+C含量为30.2%，编码226个开放阅读框（ORF），未发现已知的毒力相关基因和抗生素抗性基因，基因组与Kayvirus属葡萄球菌噬菌体有较高的同源性。[结论] 分离到1株新的Kayvirus属金黄色葡萄球菌噬菌体，根据生物学特性和基因组研究，具有一定的潜在应用价值。

Abstract:

[Objective] To isolate Staphylococcus aureus bacteriophage from hospital sewage, observe its morphology, study its host range, biological and genetic characteristics, to lay an experimental foundation for the clinical application of bacteriophage. [Methods] Using Staphylococcus aureus ATCC25923 as the host bacterium to isolate and purify bacteriophage from hospital sewage by the double-layer agar plate assay. Observing bacteriophage morphology by transmission electron microscope, determining its optimal multiplicity of infection (optimal MOI), one-step growth curve and host range. Sequencing the whole genome, analyzing gene structure and annotating gene function. [Results] A strain of Staphylococcus aureus bacteriophage (named vB_SauH_SAP1) was isolated from hospital sewage. vB_SauH_SAP1 has a high host specificity and can only lyse 10 strains of clinical isolates of Staphylococcus (a total of 37 strains). Transmission electron microscopy observation shows an icosahedron head and a contractile tail, which belongs to Myoviridae family. The optimal MOI was 0.1, the latent phase was 10 min and lysis period was 20 min. The genome was 143375 bp in length, with a G+C content of 30.2%, encoding 226 ORFs. No known virulence-related gene or antibiotic resistance gene has been predicted. Its genome has high homology with Kayvirus Staphylococcus bacteriophages.[Conclusion] A new Kayvirus Staphylococcus aureus bacteriophage with potential application value was isolated and characterized.