Sporicidal Activity of Selected Disinfectants against Clostridium difficile

Kim, Hyo Sik; Kim, Heejung

Abstract

BACKGROUND
Clostridium difficile infection (CDI) is the predominant cause of hospital-acquired diarrhea. This study evaluated the sporicidal activities of several disinfectants against C. difficile spores.
METHODS
We used toxigenic C. difficile strains with different ribotypes for our study. We compared the sporicidal activities of Cavicide (Metrex Research Corporation, USA), Cidex OPA (Advanced Sterilization Products, USA), 1% Rely+On Virkon (Dupont, UK), 0.25% Surfanios (Laboratoires Anios, France), sodium hypochlorite (Yuhan Clorox, Korea), and 70% ethyl alcohol (Duksan, Korea) by using dilution-neutralization method. The sporicidal activity of the disinfecting agents was considered to be the inactivation factor (IF). The IF was calculated as the log10 colony forming unit (CFU) reduction of the viable count from the initial inoculums. Disinfectants were considered to be sporicidal if they showed an IF> or =4.
RESULTS
Cavicide, 70% ethyl alcohol, Rely+On Virkon, and Surfanios showed no reduction in spore counts at all exposure time. Solutions of sodium hypochlorite diluted 1:100 (> or =400 ppm available chlorine), 1:50, and 1:20 were sporicidal after 5 min, 2 min, and 30 s, respectively. Cidex OPA showed sporicidal activity after 30 min.
CONCLUSION
To prevent the transmission of CDI, at least 1,000 ppm sodium hypochlorite solution should be used to disinfect the hospital environment. Contaminated endoscopes should be disinfected with Cidex OPA for more than 30 min.