International Validation of a Methicillin-Resistant Staphylococcus aureus Risk Assessment Tool for Skin and Soft...

Area of Science:

• Infectious Diseases
• Clinical Microbiology
• Pharmacology

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant challenge in treating skin and soft tissue infections (SSTIs).
• Judicious prescribing of MRSA-active therapy is crucial to combat antimicrobial resistance.
• A previously developed MRSA risk assessment tool required international validation.

Purpose of the Study:

• To validate an existing MRSA risk assessment tool internationally.
• To evaluate the predictive performance of the tool for MRSA in patients with SSTI.

Main Methods:

• A multicenter, prospective cohort study involving adults with purulent SSTI across seven international sites.
• Calculation of MRSA risk scores based on patient history (infection/colonization, hospitalization, antibiotics, comorbidities).
• Comparison of predictive performance using area under the receiver operating characteristic curves (aROC) for risk score, surveillance percentage, and estimated MRSA probability.

Main Results:

• Higher MRSA risk scores correlated significantly with MRSA presence (P < 0.001).
• The MRSA risk score (aROC: 0.748) and estimated MRSA probability (aROC: 0.781) were significantly more predictive than surveillance percentage (aROC: 0.646).
• An MRSA risk score of 0 demonstrated a negative predictive value >90% when MRSA prevalence was ≤30%.

Conclusions:

• The MRSA risk score and estimated MRSA probability offer superior prediction of MRSA compared to surveillance percentages.
• A risk score of zero indicates low MRSA likelihood, potentially reducing unnecessary empiric MRSA coverage in select patients.
• Further research is needed to assess the impact of this tool on prescribing patterns and clinical outcomes before widespread implementation.