The effect of targeted decolonization on methicillin-resistant Staphylococcus aureus colonization or infection in a surgical intensive care unit

Abstract

Background: The effect of decolonization on the control of methicillin-resistant Staphylococcus aureus (MRSA) may differ depending on intensive care unit (ICU) settings and the prevalence of antiseptic resistance in MRSA. Methods: This study was conducted in a 14-bed surgical ICU over a 40-month period. The baseline period featured active surveillance for MRSA and institution of contact precautions. MRSA decolonization via chlorhexidine baths and intranasal mupirocin was implemented during a subsequent 20-month intervention period. Pre-post and interrupted time series analysis were used to evaluate changes in the clinical incidence of hospital-acquired MRSA colonization or infection. MRSA isolates were tested for the presence of qacA/B genes and mupirocin resistance. Results: In pre-post analysis, the clinical incidence of MRSA significantly decreased by 61.6% after implementation of decolonization (P<.001). Meanwhile, interrupted time series analysis showed decreases in both the level (beta =-0.686; P=.210) and trend (beta =-0.011; P=.819) of clinical MRSA incidence, but these changes were not statistically significant. Of 169 MRSA isolates, 64 (37.8%) carried the qacA/B genes, and 22 (13.0%) showed either low- (n=20) or high-level (n=2) resistance to mupirocin. Low-level mupirocin resistance significantly increased from 0%-19.4% during the study period. Conclusion: Although decolonization using antiseptic agents was helpful to decrease hospital-acquired MRSA rates, the emergence of antiseptic resistance should be monitored. (C) 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.