Researchers Evaluate Efficacy of Several Aggressive Chemistries for Reduction of C. diff Spores


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 handwashing is limited. Edmonds et al. (2013) sought 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 subjects 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 percent chlorinated lime, 2000 ppm peracetic acid, or 1,000 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.

The researchers conclude that 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.

Reference: S Edmonds, C Zapka, J Rutter, C Fricker, J Arbogast, D Macinga and R McCormack. Poster presentation P027 at the 2nd International Conference on Prevention and Infection Control (ICPIC 2013) : Semmelweis versus C. difficile: efficacy of chlorinated lime and other hand hygiene interventions. Antimicrobial Resistance and Infection Control 2013, 2(Suppl 1):P27  doi:10.1186/2047-2994-2-S1-P27

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