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

Abstract

Preventing methicillin-resistant Staphylococcus aureus (MRSA) transmission in health care facilities where MRSA is endemic is challenging yet critical. We sought to determine the effectiveness of 2 bundles of interventions for preventing MRSA transmission in a neonatal intensive care unit (NICU). 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-1 measures except that the real-time polymerase chain reaction test replaced culture for the detection of MRSA. 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). Despite an increasing incidence of MRSA in community settings, preventing MRSA transmission within a NICU is achievable through implementation of optimal intervention strategies.