Clin Infect Dis
Does universal mupirocin negate the value of MRSA nasal PCR in the ICU?
Clinical takeaway: MRSA nasal PCR swabs maintain strong negative predictive value after universal mupirocin decolonization, including when obtained within 7 days of initiation, and can be used confidently to support antimicrobial stewardship.
In this retrospective cohort study of 1,034 adult ICU patients, investigators compared MRSA PCR negative predictive value (NPV) when swabs were collected before mupirocin initiation vs. within 7 days and more than 7 days after starting universal decolonization. Across all groups, NPV remained consistently high, differing by only 0.3% for tests obtained within 7 days and −0.4% for those collected beyond 7 days compared with pre-decolonization testing. MRSA PCR performed within 7 days of mupirocin initiation met noninferiority thresholds, indicating that decolonization did not meaningfully impair test reliability.
Overall, the findings support continued use of MRSA nasal PCR to inform empiric anti‑MRSA therapy decisions in ICUs that employ universal mupirocin decolonization, without the need to modify interpretation based on recent treatment.
Source: Ito AS, et al. (2026, March 16). Clin Infect Dis. Evaluation of the impact of universal mupirocin decolonization in intensive care units on the utility of MRSA PCR nasal swab testing