Containment of a Methicillin-resistant Staphylococcus aureus (MRSA) Outbreak in a Neonatal Intensive Care Unit.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a challenging nosocomial pathogen in the last 50 years. OBJECTIVES: To describe an investigation and containment of an MRSA outbreak in a neonatal intensive care unit (NICU). METHODS: Our NICU is a 25-bed level III unit. Almost 540 neonates are admitted yearly. The index case was an 8 day old term baby. MRSA was isolated from his conjunctiva. Immediate infection control measures were instituted, including separation of MRSA+ carriers, strict isolation, separate nursing teams, and screening of all infants for MRSA. Healthcare workers and parents of positive cases were screened and re-educated in infection control measures. New admissions were accepted to a clean room and visiting was restricted. MRSA isolates were collected for molecular testing. RESULTS: MRSA was isolated from five infants by nasal and rectal swabs, including the index case. Screening of healthcare workers and families was negative. Two MRSA+ patients already known in the pediatric intensive care unit (PICU) located near the NICU were suspected of being the source. All NICU isolates were identical by pulsed-field gel electrophoresis but were different from the two PICU isolates. The NICU and one of the PICU isolates were defined as ST-5 strain by multilocus sequence typing. One PICU isolate was ST-627. All NICU isolates were Panton-Valentine leukocidin negative and SCCmec type IV. No further cases were detected, and no active infections occurred. CONCLUSIONS: A strict infection control policy and active screening are essential in aborting outbreaks of MRSA in the NICU.