Successful control of a methicillin-resistant Staphylococcus aureus outbreak in a burn intensive care unit by addition of universal decolonization with intranasal mupirocin to basic infection prevention measures

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is frequently implicated in health care–associated outbreaks in burn intensive care units, incurring substantial morbidity and mortality to these high-risk patients and excess costs to health care systems. Methods: MRSA health care–associated infections (HAIs) were noted before and after the implementation of basic infection prevention measures and the subsequent implementation of universal decolonization with intranasal mupirocin. Pulsed-field gel electrophoresis was used to determine the relatedness of clinical isolates. A case-control study was conducted to characterize the risk factors for MRSA HAIs. Results: Basic interventions failed to decrease the rate of MRSA HAIs, although compliance with these interventions was high throughout the study. MRSA HAIs decreased from 8.53 HAIs per 1,000 patient days before the implementation of intranasal mupirocin to 3.61 HAIs per 1,000 patient days after the implementation of intranasal mupirocin (P = .033). Pulsed-field gel electrophoresis disclosed 10 unique clones with no large clusters. The case-control study revealed a significant association between MRSA HAIs and lengths of stay, body surface area burned, intubation, pressor requirement, leukocytosis, lactic acidosis, development of pneumonia, MRSA colonization, and death. Conclusions: Basic environmental and behavioral interventions fell short of controlling a low-count, sporadic, and multiclonal MRSA outbreak in the burn intensive care unit of a tertiary medical center. However, the added implementation of universal decolonization with intranasal mupirocin was effective. Burn victims with greater disease severity were at higher risk for MRSA HAIs.