Systematic Review of the Clinical Utility of Methicillin-Resistant Staphylococcus aureus (MRSA) Nasal Screening for MRSA Pneumonia

Objective: To describe the diagnostic performance characteristics of methicillin-resistant Staphylococcus aureus (MRSA) nasal screening for patients with pneumonia. Data Sources: PubMed and Scopus were searched from 1 January 1990 to 12 December 2018 using terms methicillin-resistant Staphylococcus aureus AND (screening OR active surveillance OR surveillance culture OR targeted surveillance OR chromogenic OR PCR OR polymerase chain reaction OR rapid test) AND (nares OR nasal) AND (pneumonia OR respiratory). Study Selection and Data Extraction: Relevant studies in humans and English were considered. Data Synthesis: In all, 19 studies, including 21 790 patients, were included. Nasal screening for MRSA had a high negative predictive value (NPV; 76% to 99.4% for relevant studies) across all types of pneumonia. Time from nasal screening to culture varied across studies. Relevance to Patient Care and Clinical Practice: MRSA nasal screening has a high NPV for MRSA involvement in pneumonia. Utilizing this test for antimicrobial stewardship program (ASP) purposes can provide a valuable tool for reducing unwarranted anti-MRSA agents and may provide additional cost benefits. A cutoff of 7 days between nasal swab and culture or infection onset seems most appropriate for use of this test for anti-MRSA agent de-escalation for ASP purposes. Conclusions: Consideration for the inclusion of the utility of MRSA nasal screening in MRSA pneumonia should be made for future pneumonia and ASP guidelines. Additional studies are warranted to fully evaluate specific pneumonia classifications, culture types, culture timing, and clinical outcomes associated with the use of this test in patients with pneumonia.