A stepwise approach to control an outbreak and ongoing transmission of methicillin-resistant Staphylococcus aureus in a neonatal intensive care unit

Background: Preventing methicillin-resistant Staphylococcus aureus (MRSA) transmission in health care facilities where MRSA is endemic is challenging yet critical. Objective: We sought to determine the effectiveness of 2 bundles of interventions for preventing MRSA transmission in a neonatal intensive care unit (NICU). Methods: This retrospective cohort study included infants admitted to our NICU between September 1, 2004, and March 31, 2009. Following a MRSA outbreak between September 2004 and September 2005, preventing ongoing MRSA transmission remained a challenge. In July 2006, bundle-I, including culture-based active surveillance, preemptive contact precaution for up to 72 hours for new admissions, and cohorting assignment of direct caregivers was introduced for eradicating MRSA transmission. Bundle-II began in April 2007 and included bundle-I measures except that the real-time polymerase chain reaction test replaced culture for the detection of MRSA. Results: This study identified 218 infants who developed MRSA infection or colonization and 151 instances of MRSA transmission during the study period. After instituting bundle-II, the transmission rate declined from 2.9 to 2.1 per 1000 patient-days-at-risk (incidence rate ratio, 1.4; 95% confidence interval: 0.9-2.2), and hospital-acquired MRSA infections declined from 1.3 to 0.5 per 1000 patient-days-at-risk (incidence rate ratio, 2.5: 95% confidence interval: 1.1-5.8). Conclusion: Despite an increasing incidence of MRSA in community settings, preventing MRSA transmission within a NICU is achievable through implementation of optimal intervention strategies.