Isolation and Analysis of the Biological Characteristics of a Novel Bacteriophage vB_SauP_P992 Against Staphylococcus aureus

Abstract

Background: Staphylococcus aureus is one of the most virulent pathogens inducing various diseases in humans and animals. Dis-turbingly, the degree and rate of drug resistance in this pathogen have sharply increased and have become a global concern. Objectives: This study analyzed the lytic activity and the biological characteristics of a mitomycin C-induced bacteriophage from S. aureus isolated and identified from hospital sewage to explore novel antibacterial therapeutic strategies for the clinical treatment of drug-resistant S. aureus, including urinary tract infections caused by MRSA strains. Methods: The new bacteriophage vB_SauP_P992, which can effectively lyse the MRSA strain, was successfully isolated and purified using the double agar plate method. In this regard, pH sensitivity, one-step growth curve, the optimal multiplicity of infection (MOI), thermo-sensitivity, phage host range, and the effects of organic reagents on phage activity were determined. Results: Electron microscopic results showed that the bacteriophage head was hexagonal with a non-contractile tail and could form a single, neatly-bordered plaque. Moreover, the optimal MOI was 0.1. The one-step growth curve showed a bacteriophage incubation period of about 20 min, a lysis period of 90 min, and a burst size of about 65.8 PFU per infected cell. The bacteriophage vB_SauP_-P992 had acceptable thermal stability, pH stability, and resistance to physical and chemical factors, indicating a bacteriophage with no capsule. Conclusions: With an intense lytic activity and acceptable stability, this novel bacteriophage lays a solid foundation to enrich the bacteriophage library and better prevent and control drug-resistant S. aureus infections.