Eradication of methicillin-resistant Staphylococcus aureus in a neonatal intensive care unit: which measures for which success?

BACKGROUND

Various strategies for controlling methicillin-resistant Staphylococcus aureus (MRSA) outbreaks in neonatal intensive care units (NICUs) have been tried, with varying levels of success. We report a MRSA outbreak occurring between April 2004 and August 2007 in a 24-bed NICU in a large university hospital. We describe the difficulties involved in implementing measures to control the MRSA outbreak and the possible contribution of each measure.

METHODS

Cases were defined as neonates with MRSA obtained from either clinical cultures or surveillance cultures (from the anterior nares). Systematic screening of neonates for colonization was performed only between February and December 2005. Successive control strategies included barrier precaution and isolation in individual rooms, mupirocine ointment for neonates and health care workers, cohort isolation, hand hygiene observation, and staff training.

RESULTS

During the routine surveillance culture period (February to December 2005; 48 weeks), 46 neonates were found to be positive for MRSA and were treated with mupirocin. After December 2005, the outbreak was controlled, but the ongoing spread was not eradicated; 9 sporadic MRSA cases were detected by clinical culture up to August 2007.

CONCLUSION

The widespread use of mupirocine in staff and patients did not control the outbreak and is not recommended. The later control appeared to coincide with increased hand hygiene audits and training for staff, along with appropriate cohort isolation of neonates and cohort nursing.