Methicillin-Resistant Staphylococcus Aureus Nasal Testing Negative Predictive Value for Skin and Soft Tissue Infections
Files
Publication Date
2025
Keywords
oregon, oaa 2025
Disciplines
Medical Education | Pharmacy and Pharmaceutical Sciences
Abstract
Learning Objectives: 1. Assess the importance of MRSA nasal screening versus culture data when it comes to guiding therapy for SSTI management. 2. Identify if there are any infection characteristics that significantly impact outcome of predictive values of MRSA NAAT PCR testing. Abstract: Introduction Methicillin-Resistant Staphylococcus aureus (MRSA) NAAT PCR has been a valuable tool for de-escalating vancomycin, including for management of skin and soft tissue infections (SSTIs). However, providers have reported instances where a negative MRSA NAAT has led to narrowing antibiotics, but the wound culture revealed MRSA growth. Due to the short time for MRSA nasal swab result compared to wound culture result, this could be a common occurrence in the hospital setting. Previous research shows MRSA NAAT negative predictive value for all SSTI to be anywhere between 80% to 98.4%. In this study, we assessed the negative predictive value of MRSA NAAT PCR with SSTIs. Methods Retrospective, single center study evaluating 162 patients with diagnosis of SSTI between November 2022 to January 2025. Analyzed impact of data using sensitivity, specificity, positive predicative value, negative predictive value, positive likelihood ratio, and negative likelihood ratio. Results: This population included a majority of purulent infections (n=134, 82.7%) and patients with a diagnosis of cellulitis (n=65, 40.1%). Of the pa-tients included in this study, 92 (56.8%) had a negative MRSA NAAT PCR with no MRSA growth, 37 (22.8%) had a positive MRSA NAAT PCR with MRSA growth, 15 (9.3%) had a negative MRSA NAAT PCR with MRSA growth, and 18 (11.1%) had a positive MRSA NAAT PCR with no MRSA growth. This data calculated a negative predictive value (NPV) of 86% (95% CI, 77.6-91.7%) and a positive predicative value (PPV) of 67.3% (95% CI, 53.2-79%). Conclusion: MRSA NAAT PCR testing is a valuable tool for de-escalation; however, other factors need to be taken into consideration prior to use for de-escalation of vancomycin in the setting of SSTIs specifically
Specialty/Research Institute
Graduate Medical Education
Specialty/Research Institute
Pharmacy
