Isolation, characterization, and antibacterial activity of lytic bacteriophage against methicillin-resistant Staphylococcus aureus causing bedsore and diabetic wounds

Abstract

Background and Objectives: Phage therapy has gained interest as an alternative treatment for methicillin-resistant Staph- ylococcus aureus (MRSA)infections. The purpose of this study was to isolate and characterize an effective bacteriophage against isolates of MRSA.

Materials and Methods: Bacteriophage was isolated from hospital sewage. Lytic activity and the titers of phage lysates were measured using spot test anddouble-layer plaque assay. The phage characterization was determined through trans- mission electron microscopy. Adsorption rate, host range and stabilitytests were investigated. The latent period and burst size were estimated from a one-step growth curve. The effect of bacteriophage against MRSA biofilms wasdetermined and Real-time PCR was used to assess the effects of the bacteriophage on the expression of the biofilm-associated genes.

Results: TEM resultsshowed that the phage resembled the Cystoviridae family. Its latent period was 30 min, corresponding to about 71/43 phage particles per infected cell. Thephage had a broad host range and it was most stable at 37°C and pH 7. It was sensitive to NaCl concentrations. The expressions of the biofilm-associated genes were significantly reduced in the presence of the phage.

Conclusion: The isolated phage was effective against MRSA strains and it can be an optional strategy of controlling biofilm development.