QAPI 116 - Addition of Nasal Mupirocin to Chlorhexidine Baths for Prevention of Methicillin-resistant Staphylococcus aureus (MRSA) Bloodstream Infections

Background: Patients in Intensive Care Units (ICUs) are at risk of acquiring Methicillin-resistant Staphylococcus aureus (MRSA) colonization, increasing the risk of subsequent MRSA infection. Universal decolonization, with chlorhexidine baths and nasal mupirocin, has the potential to reduce MRSA bloodstream infections.

Methods: In August 2020, a protocol for nasal mupirocin twice daily for five days was added to an established practice of daily ICU chlorhexidine (CHG) baths in adult ICUs in our tertiary-care hospital. The incidence of ICU-attributable MRSA bloodstream infections in the 30-months before August 2020 (termed “pre-mupirocin” period) was compared to 30 month “post-mupirocin” period when nasal mupirocin was added to daily CHG baths. National Healthcare Safety Network (NHSN) criteria was used to define qualifying bloodstream infections.

Results: Six NHSN-qualifying MRSA bloodstream infections (0.16 cases per 1,000 ICU central-line days) occurred during the 30-month “pre-mupirocin” study period compared to one NHSN qualifying MRSA bloodstream infection (0.02 cases per 1,000 ICU central-line days) in the 30-month “post-mupirocin” study period after the addition of nasal mupirocin to daily CHG baths. (p=0.049, by one-tailed z-test)

Conclusions: This study found that adding nasal mupirocin twice daily for five days to CHG baths in adult ICUs was associated with a decreased rate of MRSA bloodstream infections. The implementation of this practice requires a multidisciplinary approach including automated orders in the electronic medical record, periodic front line care staff re-education, and financial support for decolonization supplies.