Efficacy of a Hospital-Wide Chlorhexidine Bath Admission Protocol in Preventing Hospital-Acquired Methicillin-Resistant Staphylococcus aureus Infections

Background: Hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) infections annually affect almost 21,000 patients nationwide. Randomized controlled trials have demonstrated the effectiveness of chlorhexidine gluconate (CHG) in preventing HA-MRSA infections associated with invasive procedures. Several small studies involving CHG baths to patients in the intensive care unit (ICU) have demonstrated a reduction in HA-MRSA colonization and bacteremia. However, the efficacy of CHG bathing on all inpatients, including those outside the ICU, in preventing clinically significant HA-MRSA infections remains unproven.

Objective: To evaluate the effectiveness of a CHG bath protocol on admission at reducing the incidence of HA-MRSA infection in all hospitalized patients.

Methods: A retrospective cohort analysis of HA-MRSA infections in adult inpatients was performed in a community hospital before and after initiating a CHG bath admission protocol.  HA-MRSA infection was defined by criteria set by the Centers for Disease Control, and positive pertinent cultures. The protocol was initiated in December 2008. Comparisons were made between a pre-intervention group, June through November 2008, and a post-intervention group, June through November 2009. The study was powered to detect a 50% reduction in HA-MRSA infection with 95% sensitivity. Similar calendar months were compared to account for seasonal variation.

Results: Forty-eight patients out of 23,143 admissions (0.21%) developed HA-MRSA infections during the study period. In the pre-implementation group, twenty patients out of 11,373 admissions (0.18%) developed HA-MRSA infection; this compares to 26 out of 11,821 (0.22%) after protocol implementation (p<0.67). Of the HA-MRSA infections, there was a statistically significant increase in the incidence of HA-MRSA pneumonia (p<0.021), but no statistically significant change in the incidence of sepsis, surgical/wound infections, or urinary tract infections. The CHG bathing protocol was discontinued for lack of efficacy.

Conclusions: Our intention-to-treat analysis suggests a hospital-wide protocol to administer full body CHG baths on admission does not reduce the incidence of HA-MRSA infections. Furthermore, the increasing trend of HA-MRSA pneumonia in the post-intervention group was especially concerning; with a plausible relationship to initiation of the CHG bath protocol. Variables possibly contributing to our findings include an increase in MRSA surveillance, and/or the development of CHG resistance. This is the first study to our knowledge examining the efficacy of a hospital-wide CHG bath protocol on the incidence of HA-MRSA infections. Before implementing a hospital-wide CHG bath admission protocol, further studies are warranted.