Comparison of Clostridium difficile sporicidal activity and materials compatibility of a new peracetic acid-based disinfectant and 10% household bleach

Background: A 1:10 dilution of household bleach (sodium hypochlorite) is commonly used in hospitals for decontamination of surfaces in rooms of patients with Clostridium difficile infection (CDI). However, bleach has several limitations, including corrosive effects on various materials, irritation of eyes and respiratory tracts of cleaning staff and patients, and requirement for up to 10 minutes of contact time to achieve optimal killing of C. difficile spores.

Objective: To compare the sporicidal activity and materials compatibility of a new 0.0175% peracetic acid-based disinfectant (Surface Sporicidal Disinfectant or SSD) versus a 1:10 dilution of household bleach.

Methods: To compare the in vitro activity of the disinfectants, reductions in viable spore counts of 3 strains of C. difficile were monitored after timed exposures to the disinfectants. To assess materials compatibility, the disinfectants were applied daily to several common hospital surfaces (e.g., bedrail, telephone, chair, privacy curtain, and call button), metals, polyurethane, and polycarbonate and effects were monitored over time.        

Results: Both SSD and bleach reduced recovery of spores by >4 log₁₀ colony-forming units in a time-dependent fashion; however, SSD resulted in significantly more rapid killing of spores (P <0.01) (Figure) and its activity was less susceptible to inactivation by organic material. Daily application of 1:10 bleach resulted in fading of the hospital privacy curtains and chair, whereas SSD did not. Housekeeping staff using SSD reported no respiratory or eye irritation.

Conclusions: In comparison to bleach, SSD killed C. difficile spores more rapidly, was less susceptible to inactivation by organic matter, and caused less fading of hospital curtains and chairs. Further studies are needed to assess the use of SSD in rooms of patients with CDI.