ScienceDaily (Mar. 28, 2009) — A
rigorous environmental cleaning intervention can reduce the transmission
of methicillin-resistant Staphylococcus aureus (MRSA) and other
multidrug-resistant organisms in hospital intensive care units (ICUs),
according to a new study released March 20 at the annual meeting of the
Society for Healthcare Epidemiology of America (SHEA).
Researchers found that following an enhanced cleaning protocol
reduced the spread of MRSA to patients exposed to rooms in which the
prior occupant had been colonized or infected.
The multi-modal cleaning intervention consists of three parts: a
change from use of a pour bottle to bucket immersion for applying
disinfectant to cleaning cloths; an educational campaign involving the
environmental services staff at the hospital; and feedback method using
removal of intentionally-applied marks visible only under UV light.
"We know that environmental contamination with highly
antibiotic-resistant bacteria can still occur in hospitals where
cleaning policies exceed national standards established by the CDC,"
said Rupak Datta, MPH, an MD/PhD candidate at the University of
California at Irvine. "Although the risk of acquiring MRSA and VRE is
already low, this study suggests that there are additional preventative
measures that hospitals can take to reduce the risk of transmission from
one patient to another."
The retrospective study of more than 13,000 hospital stays in10 ICUs
at a large, tertiary care academic medical center in Boston, measured
the risk of MRSA and vancomycin-resistant Enterococci (VRE) acquisition
before (Sept. 2003-April 2005) and during the cleaning intervention
(Sept. 2006-April 2008). Routine admission and weekly screenings for
MRSA and VRE were conducted during both periods providing a systematic
method to identify new cases of MRSA and VRE. During the
pre-intervention period, 3.9% of the 1,454 patients exposed to a prior
occupant with MRSA acquired the pathogen compared to just 1.5% of the
1,443 patients exposed during the intervention. Of the 1,291 patients
exposed to VRE prior to the intervention, 4.5% acquired VRE compared to
3.5% of 1,446 patients during intervention.
The study builds upon a body of research conducted by Datta and his
co-authors. In a 2006 study, they found that patients admitted to an ICU
room whose prior occupant had been infected with MRSA or VRE had as much
as a 40 percent increased risk of acquiring either pathogen, suggesting
environmental contamination could play a significant role in their
transmission. In a subsequent study, the authors showed that a
multi-modal cleaning intervention could reduce environmental cultures
for MRSA and VRE. The current study now suggests that this same
intervention reduces acquisition of these pathogens, particularly MRSA,
in subsequent room occupants.
Despite the overall reduction in MRSA and VRE acquisition, the
cleaning intervention appears to be more effective against MRSA compared
to VRE. The difference could be due to a generally higher rate of VRE
room contamination and Datta suggests it is a question for future
research.
"The results suggest that a multi-modal cleaning intervention can
reduce MRSA and, to a lesser extent, VRE transmission in high-risk
patient areas including the ICU," said Datta.
Datta and his co-authors point out that a relatively small percentage
of healthcare-associated infections (HAIs) are transmitted due to
inadequate room cleaning (constituting about five percent of all new
cases of either pathogen.) Still, there are measures hospitals can take
to put patients' minds at ease.
"Even though we know the risk is relatively low, it is unsettling for
patients admitted to hospitals to know that the health condition of the
prior room occupant could impact their risk for acquiring MRSA or
another antibiotic-resistant infection." Datta added.
The research was funded by the CDC Prevention Epicenters program and
a grant from the National Institutes of Health (NIH).
