Abstract and Introduction
Abstract
Objective. Determine whether daily bathing with chlorhexidine-based soap decreased methicillin-resistant Staphylococcus aureus (MRSA) transmission and intensive care unit (ICU)–acquired S. aureus infection among ICU patients.
Design. Prospective pre-post-intervention study with control unit.
Setting. A 1,250-bed tertiary care teaching hospital.
Patients. Medical and surgical ICU patients.
Methods. Active surveillance for MRSA colonization was performed in both ICUs. In June 2005, a chlorhexidine bathing protocol was implemented in the surgical ICU. Changes in S. aureus transmission and infection rate before and after implementation were analyzed using time-series methodology.
Results. The intervention unit had a 20.68% decrease in MRSA acquisition after institution of the bathing protocol (12.64 cases per 1,000 patient-days at risk before the intervention vs 10.03 cases per 1,000 patient-days at risk after the intervention; β, −2.62 [95% confidence interval (CI), −5.19 to −0.04]; P = .046). There was no significant change in MRSA acquisition in the control ICU during the study period (10.97 cases per 1,000 patient-days at risk before June 2005 vs 11.33 cases per 1,000 patient-days at risk after June 2005; β, −11.10 [95% CI, −37.40 to 15.19]; P = .40). There was a 20.77% decrease in all S. aureus (including MRSA) acquisition in the intervention ICU from 2002 through 2007 (19.73 cases per 1,000 patient-days at risk before the intervention to 15.63 cases per 1,000 patient-days at risk after the intervention [95% CI, −7.25 to −0.95]; P = .012)]. The incidence of ICU-acquired MRSA infections decreased by 41.37% in the intervention ICU (1.96 infections per 1,000 patient-days at risk before the intervention vs 1.15 infections per 1,000 patient-days at risk after the intervention; P = .001).
Conclusions. Institution of daily chlorhexidine bathing in an ICU resulted in a decrease in the transmission of S. aureus, including MRSA. These data support the use of routine daily chlorhexidine baths to decrease rates of S. aureus transmission and infection.
Introduction
Staphylococcus aureus is a major cause of healthcare-associated infections, particularly among critically ill patients. Methicillin-resistant S. aureus (MRSA) has caused an increasing proportion of intensive care unit (ICU)–acquired S. aureus infections in the United States over the past 20 years. Compared with methicillin-susceptible S. aureus (MSSA), MRSA infections are associated with increased costs and mortality.
Transmission of S. aureus between hospitalized patients has long been felt to primarily occur via the hands of healthcare workers. Multiple interventions have been undertaken to interrupt MRSA transmission in healthcare settings, including improving healthcare worker hand hygiene compliance, instituting contact precautions for patients colonized or infected with MRSA, performing active surveillance to identify asymptomatic colonization and prompt earlier contact precautions, and decolonizing MRSA-colonized patients. Chlorhexidine gluconate, a topical antiseptic, has been used in preprocedural skin antisepsis and to eliminate MRSA carriage. Recent data have emerged to support the use of chlorhexidine skin antisepsis to prevent the transmission of drug-resistant organisms, such as vancomycin-resistant enterococci (VRE) and MRSA, in ICUs. Several studies have evaluated the use of chlorhexidine-based skin antisepsis, with or without intranasal therapy to decolonize MRSA-colonized ICU patients, and reported decreases in MRSA acquisition, colonization, and infection. Additionally, bathing all ICU patients daily with a chlorhexidine-based soap has been shown to decrease acquisition of MRSA, colonization with MRSA and MRSA infection. However, few studies examining the effect of routine daily chlorhexidine bathing on S. aureus transmission and infection have accounted for secular trends in colonization pressure because of changes in MRSA prevalence or changes in patient mix among patients admitted to the ICU. Additionally, few studies have concomitantly compared the use of chlorhexidine in intervention units with its use in nonintervention units.
The objective of this study was to determine whether a daily bathing protocol with a chlorhexidine-based soap decreased intra-unit MRSA transmission among ICU patients. A secondary goal was to determine whether chlorhexidine-bathing reduced intra-unit overall S. aureus (ie, regardless of susceptibility to methicillin) transmission and ICU-acquired S. aureus infection. These outcomes were compared with outcomes in an ICU in which bathing with nonmedicated soap was performed. The use of time series methodology allowed us to address potential confounders, such as temporal trends in patient mix and the prevalence of S. aureus colonization at ICU admission over time.