Clinical utility of negative methicillin-resistant Staphylococcus aureus (MRSA) nasal surveillance swabs in skin and skin structure infections

Published:December 24, 2021DOI:


      • There is increasing evidence that methicillin-resistant Staphylococcus aureus (MRSA) nasal swabs have a high negative predictive value in skin and skin structure infections (SSSIs).
      • Negative MRSA nasal swabs have potential to decrease duration of vancomycin and other anti-MRSA therapy in SSSIs.
      • Implementation of MRSA nasal swabs and their utility in potential de-escalation may contribute to antimicrobial stewardship goals.



      Negative methicillin-resistant Staphylococcus aureus (MRSA) nasal swabs have a high negative predictive value of approximately 99% in respiratory infections. There is, however, a lack of data evaluating its use beyond respiratory infections.


      We conducted a retrospective analysis to determine the clinical utility of MRSA swabs for identifying MRSA-associated skin and skin structure infections (SSSIs) and the potential effects on antimicrobial stewardship efforts. Baseline characteristics, culture data, and antibiotic data were collected to determine the difference in duration of vancomycin therapy. Positive predictive value, negative predictive value, sensitivity, and specificity were secondary outcomes.


      A total of 473 patients were included, of which 156 patients had a positive MRSA nasal swab and 317 patients had a negative swab. The median duration of vancomycin was 4 days in the positive group and 3 days in the negative group (P = .01). The positive predictive value and negative predictive value were 22.4% and 97.5%. The sensitivity and specificity were 81.4% and 71.9%.


      Patients with a negative MRSA nasal swab received approximately 1 day less of vancomycin, which represented a decrease in drug administered. The negative predictive value for SSSIs is promising, showing potential for the role of MRSA nasal swabs in de-escalating therapy.

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