Infection Prevention of Methicillin-Resistant Staphylococcus aureus in a Neonatal Intensive Care Unit

BACKGROUND: In December 2001, methicillin-resistant Staphylococcus aureus (MRSA) was identified in an infant in a level-III, 45-bed neonatal intensive care unit (NICU). Epidemiologic measures to contain this organism will be described. METHODS: Infected and colonized infants were placed on contact precautions (gloves and gowns for all contact), cohorted, and treated with a 1/4-strength betadine bath and mupirocin for 5 days. Other measures include environmental cleaning, observation of infection control practices, and surveillance cultures of all infants semiweekly. Intermittently, surveillance cultures are performed on healthcare workers (HCWs). Colonized HCWs are treated with mupirocin for 5 days. Genetic typing was performed on all isolates. RESULTS: Through December 2003, 65 infants have been identified with MRSA infection (7) or colonization (58). Infected cases were confined to the first 8 weeks of the initial case. Several different strains of MRSA have been identified by pulsed-field gel electrophoresis (PFGE), but two strains, B1 and A9, are predominant in two separate events. From December 2001 to June 2002, the strain of MRSA was identified as PFGE B1 in 21 infants. Beginning in May 2002, the strain was identified as PFGE A9 in 18 infants. Fourteen HCWs were colonized with MRSA. Two HCWs harbored strain B1, and one HCW harbored strain A9. In subsequent cultures, one HCW had strain B1 for a second time and all other HCWs have been negative for MRSA. CONCLUSIONS: Our epidemiologic findings indicate that we have infant-HCW-infant transmission. While colonization continues, our control measures have prevented infection during the last 23 months.