November 21, 2017
3 min read

C. difficile persists most frequently in floor corners after disinfection

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Clostridium difficile persists most frequently in floor corners and on bathroom floors after routine and terminal cleaning of hospital rooms, recent study findings showed.

Additionally, researchers identified nurse call buttons as the most highly contaminated surface after both routine and terminal cleaning, and said added attention must be given to manually clean ceiling vents that are potentially contaminated with C. difficile spores.

The most common cause of health care-associated diarrhea, C. difficile is resistant to some disinfectants, difficult to eradicate through cleaning and can persist for up to 5 months in the environment, A. Peter R. Wilson, MA, MD, FRCP, FRCPath, of University College London Hospitals, and colleagues reported in Infection Control & Hospital Epidemiology.

During a cohort study at a London teaching hospital, Wilson and colleagues found that the persistence of C. difficile was widespread in the environment but declined following whole-room aerial decontamination with hydrogen peroxide, which the hospital has introduced to supplement manual cleaning following patient discharge.

“In the health care setting, acquisition of C. difficile infection (CDI) is associated with environmental contamination as much as it is associated with person-to-person spread,” they wrote “Previous occupants of the same bed area who were infected with pathogens that survive well in the environment are a risk factor for acquisition of the pathogen.”

Over the course of 1 year, Wilson and colleagues used sponge swabs to sample 16 commonly touched or difficult-to-clean surfaces in single-patient isolation rooms or bed areas in patient bed bays before and after terminal cleaning or hydrogen peroxide disinfection. In all, 2,529 sites from 146 rooms and 44 bays were sampled. The findings included results from bed areas that were occupied by patients who were known to be infected or colonized with C. difficile, and areas where the C. difficile status of the patient was unknown.

Overall, C. difficile was found on 131 of 572 surfaces (22.9%) before terminal cleaning, 105 of 959 surfaces (10.6%) after terminal cleaning, and 43 of 967 surfaces (4.4%) after hydrogen peroxide disinfection, Wilson and colleagues reported. They said floor corners and bathroom floors were the sites most commonly positive for C. difficile after routine cleaning and disinfection, and that it persisted most frequently in floor corners, being found on 97 of 334 surfaces (29%) after disinfection.

Hydrogen peroxide was effective overall at reducing C. difficile contamination but less effective on bathroom floors, of which nine of 15 (15.8%) surfaces remained contaminated. They said six of 19 (31.6%) tested surfaces from ceiling vents were positive after terminal cleaning — the only place unaffected by this disinfection step.


“Ceiling vents must be sealed during decontamination to prevent leakage of hydrogen peroxide to other areas. Consequently, C. difficile spores remained in the vents,” they wrote. “Ceiling vents and vent covers must therefore be included in all manual cleaning protocols. If local infrastructure allows, isolating air flow instead of using covers may be beneficial to allow hydrogen peroxide decontamination of vents.”

Wilson and colleagues said past findings have also highlighted the effectiveness of hydrogen peroxide systems at reducing C. difficile in the environment. They said previous studies have shown the effectiveness of hydrogen peroxide or ultraviolet-C light to reduce the incidence of CDI. An article published the same day in Infection Control & Hospital Epidemiology included findings from researchers who reviewed 13 studies examining the effect of UV-C light as a no-touch disinfection technology and found that it may be effective at preventing CDI and vancomycin-resistant enterococci infection.

Wilson and colleagues noted that the contamination of nurse call buttons in their study may mean they are an important reservoir for C. difficile, highlighting the importance of hand hygiene policies for staff, patients and visitors.

“Manual cleaning was often insufficient to remove all C. difficile from the environment,” they wrote. “Identification of highly contaminated sites led to a temporary improvement in terminal cleaning of affected areas and reduction in C. difficile isolated. Removal of soil was important in improving the long-term efficacy of hydrogen peroxide decontamination with the aim of reducing the risk of transmission.” – by Gerard Gallagher


Marra AR, et al. Infect Control Hosp Epidemiol. 2017;doi:10.1017/ice.2017.226.

Yui S, et al. Infect Control Hosp Epidemiol. 2017;doi:10.1017/ice.2017.227.

Disclosure s : Wilson reports serving on advisory panels for 3M and Merck. All other authors report no relevant financial disclosures.