Reviewed by Jose A. Lucar, MD, FIDSA – The George Washington University
A recent retrospective multicenter cohort study evaluated whether universal nasal mupirocin decolonization affects the negative predictive value (NPV) of MRSA PCR nasal swab testing among ICU patients. The study included 1,034 adults admitted to ICUs who received mupirocin as part of a universal decolonization strategy. MRSA PCR testing performed within seven days after initiation of mupirocin demonstrated a high NPV (99.1%) that was non‑inferior to testing performed prior to decolonization (98.8%). Measures of test performance, including sensitivity and specificity, were comparable between the pre‑decolonization and 0–7‑day post‑decolonization groups, suggesting no meaningful change in overall test performance during this interval. MRSA PCR testing conducted more than seven days after mupirocin initiation also demonstrated a high NPV; however, interpretation of these results is limited by the very low incidence of MRSA infection in this subgroup. Key limitations of the study include its retrospective, observational design and the overall low incidence of MRSA infection, particularly among patients tested beyond seven days after decolonization. Additionally, the findings may not be generalizable beyond ICU settings employing universal mupirocin decolonization or to institutions with differing MRSA prevalence or mupirocin resistance patterns. Overall, these findings support that MRSA PCR nasal swab testing performed within seven days of initiating universal mupirocin decolonization is non-inferior to pre‑decolonization testing and remains a useful tool to support antimicrobial stewardship and vancomycin de‑escalation in ICU settings.
Reference:
Ito AS, Reasoner KC, Ong’uti SK, Qian ET, Zhao Z, Stern RA, Freiberg JA. Evaluation of the impact of universal mupirocin decolonization in intensive care units on the utility of MRSA PCR nasal swab testing. Clin Infect Dis. 2026 Mar 16:ciag183. doi: 10.1093/cid/ciag183. Epub ahead of print. PMID: 41834148.