Isolation and characterization of a novel Staphylococcus aureus bacteriophage, phiMR25, and its therapeutic potential

Area of Science:

• Microbiology
• Virology
• Bacteriophage Therapy

Background:

• Staphylococcus aureus is a significant human pathogen.
• Bacteriophage therapy is an emerging alternative to antibiotics.
• phiMR11 is a previously identified therapeutic phage for S. aureus.

Purpose of the Study:

• To isolate and characterize a novel bacteriophage, phiMR25, from a lysogenic S. aureus strain.
• To compare the biological and genetic features of phiMR25 with the prototype therapeutic phage phiMR11.
• To evaluate the therapeutic potential of phiMR25 against S. aureus infection in a mouse model.

Main Methods:

• Isolation of bacteriophage phiMR25 via mitomycin C induction.
• Morphological analysis and host range determination on S. aureus strains.
• Genomic sequencing and analysis of open reading frames.
• In vivo efficacy study using a lethal dose of S. aureus in mice.

Main Results:

• phiMR25, a Myoviridae bacteriophage, exhibits a broader host range than phiMR11 against S. aureus.
• phiMR25's genome is 44,342 bp with 70 predicted open reading frames, lacking toxin or resistance genes.
• phiMR25 shares genetic diversity with phiMR11, particularly in lysogenic and virion protein genes.
• Intraperitoneal administration of phiMR25 successfully rescued mice from lethal S. aureus infection.

Conclusions:

• phiMR25 is a novel bacteriophage with significant therapeutic potential against S. aureus infections.
• Its broader host range and demonstrated in vivo efficacy make it a strong candidate for phage therapy.
• phiMR25 represents a valuable alternative or adjunct to conventional antibiotic treatments for S. aureus.