Long-term use of chlorhexidine did not contribute to an increase in MRSA isolates that are resistant to the antiseptic soap among critically ill patients, according to new research.
“There has been a concern in the health care community about the impact of routine, daily chlorhexidine (CHG) bathing in fostering the spread of bacteria resistant to this agent,” David Warren, MD, PhD, associate professor of medicine in the division of infectious diseases at Washington University School of Medicine and hospital epidemiologist at Barnes-Jewish Hospital in St. Louis, said in a press release. “We did not see sustained increase in MRSA resistant to CHG.”
Warren and colleagues studied 504 randomly selected nasal isolates from patients admitted to the surgical ICU at Barnes-Jewish Hospital — 63 per year from 2005 to 2012. They found the prevalence of CHG-resistant MRSA isolates fell from 6.2% in 2005, the year daily CHG bathing replaced a once-daily bath with nonmedicated soap and water, to 0% to 1.5% from 2006 to 2008.
A spike in the prevalence of CHG resistance to 16.9% in 2009 and 2010 was most likely due to patient exposure during prior hospital admissions, the researchers found, ruling out the possibility that the daily CHG baths were a factor.
The prevalence of CHG-resistant MRSA isolates fell again to 4.6% in 2011 and was 7.7% in the final year of the study.
The researchers were unable to test all the MRSA isolates collected during the study period due to limited resources, but concluded that their findings suggest long-term CHG bathing “did not result in sustained, widespread dissemination of genes encoding for chlorhexidine tolerance.”
Further studies are needed to determine whether other ICU-based decolonization strategies will result in selection of co-resistant isolates, the researchers said. – by Gerard Gallagher
Disclosure: Warren reports serving as a consultant to Centene Corp., Novaerus Corp. and Sagentia. Please see the full study for a list of all other authors’ relevant financial disclosures.