Impact of chlorhexidine (CHG) bathing on MRSA and VRE hospital-acquired infections (HAIs) in non-ICU patients: Interim Report

Background: Recent studies found significant reductions in infection due to multi-drug resistant pathogens after implementing daily bathing with CHG in ICU patients.

Objective: Evaluate whether or not daily bathing with CHG in non-ICU patients reduces MRSA and VRE HAIs.

Methods: We are conducting a quasi-experimental study on 4 general medical units at Rhode Island Hospital.  The control group is patients admitted 1/08-12/08 who had daily bathing with soap & water.  The intervention group includes patients admitted 2/09-9/09 bathed once daily with 2% CHG cloths (Sage Products, Inc).  Nursing staff were trained with proper use of CHG cloths prior to the intervention period.  Our primary outcome measure is the incidence of MRSA & VRE HAI.  Although CHG has minimal sporicidal activity, our secondary outcome is the incidence of Clostridium difficile (C diff) HAI.  HAIs were defined using NHSN criteria.  We hypothesized that CHG bathing would reduce MRSA & VRE HAIs.  Power analysis suggests that 10,000 patients are needed in both the control and intervention groups, to show a significant difference based on a 50% reduction in combined MRSA & VRE HAIs using our 2006-2008 incidence data.  We prospectively monitored hand hygiene and isolation precaution compliance during both study periods using the same surveillance tools.

Results: The number of patients in the control and intervention groups is 5717 and 3871, respectively.  The incidence of MRSA & VRE HAIs decreased from 0.76/1000 patient days to 0.62/1000 pt days during the control and intervention periods, respectively (RR = 0.82, 95%CI 0.42-1.60, p = 0.6).  The incidence of C diff in the control and intervention periods decreased from 1.36/1000 patient days to 1.24/1000 pt days, respectively (RR=0.91 95%CI 0.56-1.49, p=0.7).  During the control and intervention periods, mean level of hand hygiene compliance on study units was 49% (1,829 observations) and 68% (1,814 observations), respectively (p=<.0001); mean level of compliance with isolation precautions was 70% (461 observations) and 80% (262 observations), respectively (p=.004).  There was no change in the hospital protocol for environmental cleaning during the study periods and no change in the nurse:patient ratio.

Conclusions: Our interim analysis demonstrates a non-significant, 18% reduction in a combined outcome measure of MRSA & VRE HAIs with daily CHG bathing of general medical inpatients.  We noted a lesser impact regarding C diff HAI.  Since compliance with hand hygiene and isolation precautions increased during the intervention period, until we do further analysis, it is unclear of how much of the HAI reduction was due to CHG use.  Lastly, it is surprising that a greater reduction in these infections was not found despite CHG bathing and increased hand hygiene and isolation precaution compliance.