Host range and molecular classification of a Staphylococcus aureus bacteriophage

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.