SAN DIEGO, CA—Monthly intranasal mupirocin prophylaxis in the neonatal intensive care unit (NICU) dramatically decreased healthcare-associated transmission of methicillin-resistant Staphylococcus aureus (MRSA) infections by 43% and cut invasive staphylococcal infections by 73%, according to a study presented at IDWeek 2015.

“While there was a limited time period for follow-up after implementation, this intervention deserves further evaluation as part of a comprehensive strategy to eliminate HAIs [healthcare-associated infections] in NICUs,” noted Elizabeth Ristagno, MD, Pediatrics, University of Louisville, Louisville, Kentucky, in explaining the rationale for the study.

“Limited data” were previously available about the utility of topical mupirocin in preventing S. aureus transmission and infection in this setting, Dr. Ristagno and coauthors reported.

A new hand hygiene program was also adopted shortly after the mupirocin prophylaxis program was initiated, according to a timeline in the team’s poster presentation at IDWeek 2015.

To determine whether MRSA transmission could be prevented in their 101-bed NICU, Dr. Ristagno and colleagues initiated a comprehensive strategy that included “weekly surveillance cultures, cohorting, contact precautions, topical mupirocin, and chlorhexidine bathing for colonized infants.” They also implemented “universal, monthly mupirocin prophylaxis as an incremental prevention strategy” and assessed healthcare-associated MRSA transmissions and rates of invasive S. aureus infections before and after mupirocin implementation.

They identified healthcare-associated MRSA transmissions by reviewing clinical cultures and weekly surveillance cultures between August 2009 and April 2015. Patients with methicillin-sensitive S. aureus or MRSA isolated from blood or cerebrospinal fluid after NICU admission were categorized as having invasive S. aureus infections.

Beginning in December 2013, “all NICU infants without a medical contraindication received monthly applications of mupirocin prophylaxis in the anterior nares and perirectal area twice daily for 5 days,” Dr. Ristagno reported. “Infants could be treated more than once.”

The investigators evaluated infection rate and transmission before and after mupirocin prophylaxis using interrupted time-series analysis (n=174,443 patient-days), with temporal changes in both rates examined using mixed-effects segmented linear regression.

After monthly mupirocin prophylaxis was initiated, the rate of healthcare-associated MRSA transmissions decreased significantly, from 23.1 events (95% confidence interval [CI]: 11.8, 41.2) to 13.2 events (95% CI: 6.9, 26.0) per 10,000 patient days (P=0.018), a 43% reduction

Rate of invasive infection also decreased significantly, from 3.0 infections (95% CI: 1.8, 7.2) to 0.8 infections (95% CI: 0.3, 1.5) per 10,000 patient days (P=0.032), a 73% reduction.

“Two of 4 infants who developed invasive infection in the postintervention period had received ≥1 mupirocin prophylaxis application,” Dr. Ristagno reported.