Literature Update - October 2008
Compiled by Dr Leon Worth, ID Physician
Hydrogen Peroxide Vapour for Clostridium difficile
Environmental Decontamination
Hydrogen peroxide vapour (HPV) has previously been shown to have activity against gram-positive and gram-negative organisms, with a
reduction in environmental organism load. Although killing of Clostridium butulinum spores has been demonstrated
in the laboratory setting, reduction of environmental contamination and nosocomial transmission of spore-producing organisms (including
Clostridium difficile) has not been demonstrated. Boyce JM et al (Infect Control Hosp Epidemiol 2008; 29:723-729)
reported the outcome of introducing HPV decontamination in the setting of a hospital-wide epidemic strain of C. difficile.
A pre- and post-intervention study was performed at the 500-bed study hospital. The pre-intervention period was June 2004 to March 2005,
and the intervention period was June 2005 to March 2006. During the intervention period, HPV decontamination was used in 5 wards with the
highest incidence of C. difficile-associated disease (CDAD). 30% liquid hydrogen peroxide was converted to HPV,
over a period of approximately 3-4 hours for a single room, and 12 hours for an entire ward. All heating, ventilation and air-conditioning
ducts were sealed using tape. Environmental sampling (quantitative culture for C. difficile) was performed before
HPV decontamination and immediately after HPV decontamination. Strain-typing of clinical isolates was performed during the first 2 months
and last 2 months of the intervention period.
Before HPV decontamination, 25.6% of environmental samples cultured C. difficile, whereas 0% of samples were culture-positive immediately
after HPV decontamination. The NAP-1 epidemic strain was present throughout the trial period. The incidence of CDAD was reduced in the 5
study wards (2.28 cases per 1000 patient-days during pre-intervention period vs. 1.28 cases per 1000 patient-days during the intervention
period). When analysis was limited to months where epidemic strain was known to be present during the pre-intervention period, hospital-wide
CDAD incidence also decreased (1.89 cases per 1000 patient-days to 0.88 cases per 1000 patient-days).
Findings suggest that surface contamination by C. difficile can effectively be reduced by HPV. The study is limited
by the fact that CDAD incidence rates were not calculated on control wards, to enable direct comparison with traditional cleaning measures.
Further studies of the impact of HPV upon CDAD rates are therefore required. Also, the practical requirements of staff training, inability
to use HPV in rooms occupied by patients, and cost implications of the intervention require further evaluation.
Detection of MRSA and VRE on Gowns and Gloves of Healthcare Workers
To determine the rates of detection of MRSA and VRE on healthcare workers’ (HCWs) gowns and gloves during routine clinical activities,
Snyder GM et al (Infect Control Hosp Epidemiol 2008; 29:583-589) performed sampling of HCW hands prior to clinical contact, from gowns
and gloves at completion of patient care activities, and from HCW hands after gown and glove removal.
The study was performed in a 29-bed ICU. HCWs were excluded from analysis if cultures of hand samples were positive for MRSA prior to
clinical contact. Overall, 137 HCWs (175 patient observations) were studied. Environmental cultures were performed of glove boxes to ensure
that baseline contamination was not a contributory factor.
Of the 137 HCWs who entered a room to provide clinical care for a patient with MRSA, VRE or both, 24 (17.5%) acquired the resistant
organism on their gloves, gown, or both. Univariate analysis identified the following statistically significant risk factors for
acquiring MRSA or VRE on gloves &/or gowns: presence of a percutaneous endoscopic gastrostomy and/or jejunostomy, HCW contact with the
endotracheal tube or tracheostomy site, and HCW contact with the head and/or neck of the patient. Time spent in the room was not
statistically associated with MRSA or VRE detection. Hands were infrequently contaminated with these organisms after removal of
gloves (2/78 patients with MRSA, 0/94 patients with VRE).
This study suggests that indwelling devices (endotracheal, percutaneous endoscopic gastrostomy and jejunostomy tubes) appear to be associated
with shedding of significant organisms in patients with MRSA or VRE colonisation. This may have implications for risk assessment or
targeting of interventions. Also, findings suggest that if gowns and gloves are not changed between individual patient contacts,
risks for transmission related to these protective measures may be significant. Reassuringly, the rate of HCW acquisition of MRSA or VRE
was low in the setting of gown and glove use.