Characterization and host range associating factors of Staphylococcus aureus bacteriophage PBSA08; Using Australian...

Area of Science:

• Microbiology
• Genetics
• Infectious Diseases

Background:

• Antimicrobial resistance, particularly from methicillin-resistant Staphylococcus aureus (MRSA), poses a significant global health threat.
• Limited antibiotic options necessitate the exploration of alternative treatments like bacteriophage (phage) therapy.
• Phage therapy offers a promising avenue for combating drug-resistant bacterial infections.

Purpose of the Study:

• To characterize a novel lytic Staphylococcus aureus phage, designated PBSA08.
• To evaluate the host range and susceptibility patterns of PBSA08 against a panel of MRSA isolates.
• To identify factors influencing MRSA susceptibility to phage PBSA08.

Main Methods:

• Characterization of phage PBSA08 using transmission electron microscopy and adsorption assays.
• Evaluation of phage susceptibility in 39 MRSA isolates using efficiency of plating (EOP) and growth kinetics assays (GKA).
• Statistical analysis, including univariate and Firth logistic regression, to identify factors associated with phage susceptibility.

Main Results:

• Phage PBSA08, a Silviavirus, possesses an icosahedral head and long tail, with efficient bacterial adsorption and a burst size of ~120 PFU/cell.
• 51.3% of MRSA isolates were susceptible to PBSA08, with susceptibility strongly correlating between EOP and GKA.
• Susceptibility was significantly associated with specific multilocus sequence types (ST30/93) and ciprofloxacin susceptibility.

Conclusions:

• PBSA08 exhibits therapeutic potential against MRSA, especially community-associated lineages like ST93.
• Further investigation into incorporating PBSA08 into phage cocktails for prevalent MRSA clones is recommended.
• Phage therapy presents a viable strategy to address the challenge of MRSA infections.