P027: Semmelweis versus C. difficile: efficacy of chlorinated lime and other hand hygiene interventions

Clostridium difficile infection is a significant issue in healthcare facilities, and proper hand hygiene is recommended to help prevent C. difficile transmission. It is known that alcohol based-handrubs are ineffective at killing C. difficile spores and recent studies demonstrate that the efficacy of hand washing is limited.

The objective of this study was to evaluate several aggressive chemistries including chlorinated lime (the Semmelweis hand disinfection procedure) for reduction of C. difficile spores.

A modification of the ASTM method E1174 was used to evaluate C. difficile spore removal and inactivation. Approximately 1x10⁶ spores of non-toxigenic C. difficile ATCC #700057 were distributed onto the palms of subject’s hands. A series of hand hygiene procedures were evaluated including a 30-second non-antimicrobial handwash and a 5 minute hand disinfection procedure with a scrub brush using 4% chlorinated lime, 2000 ppm peracetic acid, or 1000 ppm acidified bleach. Log₁₀ reductions from baseline for each product were compared using ANOVA and post-hoc analysis (P<0.05) to identify statistically significant differences.

The handwash, acidified bleach, peracetic acid, and chlorinated lime achieved log₁₀ reductions of 0.66, 0.79, 1.64, and 2.45, respectively. Although log₁₀ reductions were low, those for chlorinated lime and peracetic acid were statistically superior to acidified bleach and the non-antimicrobial handwash.

These data further reinforce that elimination of C. difficile spores from hands is very difficult. The two best chemistries, peracetic acid and chlorinated lime, still only achieved log reductions of <2.5 log₁₀, despite aggressive and lengthy application procedures not feasible for healthcare workers. These data reinforce the need for contact precautions including gloving when caring for a C. difficile infected patient; and the importance of cleaning and disinfection to reduce environmental spore contamination. Further research is needed to identify hand hygiene approaches to effectively eliminate C. difficile from hands and to reduce patient safety risk.

None declared