Isolation and Characterization of a Lytic Staphylococcus aureus Phage WV against Staphylococcus aureus Biofilm.

Background: Staphylococcus aureus is a Gram-positive, pathogenic bacterium that causes a wide range of symptoms in humans and can form biofilm, which is a multicellular community of microorganisms that attaches to nonbiological and biological surfaces.

Methods: Here, we aimed to isolate and characterize an S. aureus phage and examine the bactericidal activity alone and in conjunction with streptomycin treatment.

Results: We isolated a virulent phage, WV, from a slaughterhouse in Jiangsu, China. This strain belonged to the family Myoviridae and presented a genome size of 141,342 bp. The optimal pH of the preservation buffer was 6-7, optimal growth temperature was 37°C, and optimal multiplicity of infection was 0.01. Phage WV can sterilize most clinical strains of S. aureus that had been isolated from clinical patients in the First People's Hospital of the Yunnan Province. Against low-concentration S. aureus culture, streptomycin demonstrated a greater antibiofilm effect than that of phage WV. By contrast, in high-concentration S. aureus culture, phage WV demonstrated greater antibiofilm effect than that of streptomycin. The use of phage WV and streptomycin together had a substantially greater overall antibiofilm effect than that achieved using either component alone.

Conclusion: This study provides strong evidence for the effectiveness of phage application for the reduction of S. aureus biofilm growth and suggests that phages can be considered as a viable alternative to antibiotics in clinical settings.