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

•Decolonization using chlorhexidine baths and intranasal mupirocin helped reduce methicillin-resistant Staphylococcus aureus colonization or infection in a surgical intensive care unit.•Mupirocin resistance and the presence of qacA/B genes, which are associated with chlorhexidine resistance, in Staphylococcus aureus was not uncommon.•Low-level mupirocin resistance was significantly increased from 0% to 19% during a 40-month study period.

BackgroundThe 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.MethodsThis 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.ResultsIn 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 (β = −0.686; P = .210) and trend (β = −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.ConclusionAlthough decolonization using antiseptic agents was helpful to decrease hospital-acquired MRSA rates, the emergence of antiseptic resistance should be monitored.