Development and Evaluation of a Sensitive Bacteriophage-Based MRSA Diagnostic Screen.

Area of Science:

• Microbiology
• Molecular Biology
• Infectious Diseases

Background:

• Engineered bacteriophages offer sensitive, rapid, and low-cost bacterial detection.
• Methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization is a key factor in hospital-acquired infections and antibiotic stewardship.
• Accurate MRSA diagnostics are essential for infection control and treatment strategies.

Purpose of the Study:

• To develop and evaluate a novel phage-based diagnostic screen for MRSA nasal swab specimens.
• To assess the sensitivity and specificity of the screen in identifying MRSA.
• To determine the efficacy of the screen in a human nasal matrix.

Main Methods:

• Utilized two luciferase reporter phages targeting genetically diverse Staphylococcus aureus.
• Incorporated cefoxitin to differentiate MRSA from susceptible strains.
• Tested the screen with clinical isolates, spiked nasal specimens, and competing microbial species.

Main Results:

• The screen identified 97.7% of clinical MRSA isolates at low concentrations.
• Accurately yielded negative results for 93.5% of non-MRSA Staphylococcus aureus isolates.
• Successfully detected MRSA in 100% of spiked nasal specimens, even with competing species present.

Conclusions:

• The developed six-hour screen demonstrates high sensitivity and specificity for MRSA detection in nasal swabs.
• This phage-based diagnostic tool is effective both in vitro and within a human nasal matrix.
• The screen holds significant potential for improving MRSA diagnostics, infection control, and antibiotic stewardship.