Beyond the “Hawthorne Effect”: Reduction of Clostridium difficile Environmental Contamination through Active Intervention to Improve Cleaning Practices

Background:

Several recent publications have raised concerns that bleach may be less effective for eradication of Clostridium difficile spores from environmental surfaces than new technologies such as hydrogen peroxide vapor. Because bleach is effective in killing spores in vitro, we hypothesized that the reduced efficacy of bleach disinfection is attributable to inadequate application by housekeeping staff rather than failure of the product.

Objective:

To examine the efficacy of bleach disinfection of C. difficile spores in hospital rooms before and after interventions to improve housekeeping cleaning.

Methods:

We performed a 3-stage intervention:  1). Baseline observations of housekeeping cleaning practices; 2). Education of housekeeping in combination with direct observation of staff during room cleaning; 3). Direct supervision of housekeeping staff cleaning practices to ensure correct application of bleach. A commercial bleach product Clorox® Clean-Up® (Oakland, Ca) containing 18,400 parts per-million sodium hypochlorite was used in all rooms. To assess the efficacy of bleach disinfection, we applied non-toxigenic C. difficile spores to high-touch surfaces (i.e., the bedrail, lateral edge of the bedside table, and drawer handles) before cleaning and cultured the sites after cleaning. 

Results:

The figure shows the percentages of positive cultures for C. difficile spores after housekeeping cleaning during each phase of the intervention. Prior to the intervention, 19 of 30 (63%) environmental surfaces were positive for C. difficile after housekeeping cleaning; observations indicated that the high-touch surfaces were often not cleaned adequately and bleach was frequently wiped off surfaces without allowing sufficient contact time. During the period of education and direct observation of cleaning practices, the percentage of positive cultures was significantly reduced (9 of 45, 20%; P <0.001) and observations indicated that high-touch surfaces were still not consistently cleaned.  During the period of direct supervision of housekeeping staff, 0 of 30 culture sites were positive (P <0.001).

Conclusions:

When applied correctly, bleach is very effective in eliminating C. difficile spores from surfaces in hospital rooms. Although simple interventions such as education and observation of housekeeping staff can improve environmental disinfection, strategies such as direct supervision of cleaning may be required to attain optimal results.