Control of Methicillin-Resistant Staphylococcus aureus in a Neonatal Intensive Care Unit by Modification of 2003 Society for Healthcare Epidemiology of America Guideline for Preventing Transmission of Resistant Pathogens

BACKGROUND: Invasive methicillin-resistant Staphylococcus aureus (MRSA) infection as a cause of death in hospitalized infants is rare and has not previously occurred in Arkansas Childrenʹs Hospital (ACH) neonatal intensive care unit (NICU). In August 2003, however two infants developed MRSA pneumonia and subsequently died. Anterior nares cultures during this outbreak found two additional infants colonized. In the first 7 months of 2003, the rate of MRSA among Staphylococcus aureus in ACH NICU was 75% (21/28). As part of control measures, we reviewed and modified the Society for Healthcare Epidemiology of America (SHEA) guideline for resistant pathogens published in 2003 for implementation. METHODS: After review of the guideline by the Hospital Infection Control Committee, the following interventions were selected: 1) cohorts of colonized/infected infants were established, 2) alcohol gel hand disinfectant was introduced, 3) admission surveillance cultures of the anterior nares were performed, 4) point prevalence surveys were conducted, and 5) an antibiotic susceptibility pattern, DNA sequence analysis of the staphylococcal protein A gene (SPA), and pulsed-field gel electrophoresis (PFGE) were reviewed to determine the similarity of MRSA isolates. RESULTS: Antibiotic Susceptibility pattern, SPA, and PFGE revealed that one pattern was responsible for this cluster of invasive disease in the initial group of infants. A point prevalence survey conducted in September of current high-risk NICU patients found four infants (hospitalized 25–197 days) colonized with MRSA; none matched the outbreak isolate. Because of the concern of unrecognized MRSA from other hospitals, admission cultures were collected between October and December. Three newly admitted infants were colonized with MRSA – two 25-week-premature newborns (day of life 58 and 10) and one 38-week-premature newborn (day of life 1) from separate facilities. Another point prevalence survey in December found two infants colonized (admission culture negative); none matched the outbreak isolate. The rate of MRSA among Staphylococcus aureus had declined to 45% (18/40) by January 2004. CONCLUSION: Even though it is labor-intensive and costly to implement (microbiology laboratory charges totaled $19,903.02), this SHEA guideline was a crucial component for control of MRSA in our NICU.