Sporicidal activity of two disinfectants against Clostridium difficile spores
The sporicidal activity of an odour-free peracetic acid-based disinfectant (Wofasteril) and a widely-used dichloroisocyanurate preparation (Chlor-clean) was assessed against spores of the hyper-virulent strain of Clostridium difficile (ribotype 027), in the presence and absence of organic matter. In environmentally clean conditions, dichloroisocyanurate achieved a >3 log10 reduction in 3 minutes, but a minimum contact time of 9 minutes was required to reduce the viable spore load to below detection levels. Peracetic acid achieved a >3 log10 reduction in 30 minutes and was overall significantly less effective (P<0.05). However, in the presence of organic matter - which reflects the true clinical environment - there was no significant difference between the sporicidal activity of dichloroisocyanurate and peracetic acid over a 60-minute period (P=0.188). Given the greater occupational health hazards generally associated with chlorine-releasing agents, odour-free peracetic acid-based disinfectants may offer a suitable alternative for environmental disinfection.
Available from: Tony Worthington
- "Contamination of the clinical environment with spores of C. difficile is a key factor associated with the spread of CDI. Furthermore, patients with CDI excrete in excess 100 C. difficile spores and cells per gram of faeces (Wilcox 2003) and sporicidal agents, including bleach and peracetic acid, are required to eliminate these spores from the environment (Wheeldon et al. 2008b). Clostridium difficile infection occurs in susceptible patients following ingestion of spores from the environment, after which, the irreversible process of spore germination occurs in the small intestine giving rise to the metabolically active vegetative forms of C. difficile which produce the exotoxins associated with disease in the large intestine (Poutanen and Simor 2004; Moir 2006). "
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ABSTRACT: To investigate the influence of chemical and physical factors on the rate and extent of germination of Clostridium difficile spores.
Germination of C. difficile spores following exposure to chemical and physical germinants was measured by loss of either heat or ethanol resistance. Sodium taurocholate and chenodeoxycholate initiated germination together with thioglycollate medium at concentrations of 0.1-100 mmol l(-1) and 10-100 mmol l(-1) respectively. Glycine (0.2% w/v) was a co-factor required for germination with sodium taurocholate. There was no significant difference in the rate of germination of C. difficile spores in aerobic and anaerobic conditions (P > 0.05) however, the initial rate of germination was significantly increased at 37 degrees C compared to 20 degrees C (P < 0.05). The optimum pH range for germination was 6.5-7.5, with a decreased rate and extent of germination occurring at pH 5.5 and 8.5.
This study demonstrates that sodium taurocholate and chenodeoxycholate initiate germination of C. difficile spores and is concentration dependant. Temperature and pH influence the rate and extent of germination.
This manuscript enhances the knowledge of the factors influencing the germination of C. difficile spores. This may be applied to the development of potential novel strategies for the prevention of C. difficile infection.
Journal of Applied Microbiology 12/2008; 105(6):2223-30. DOI:10.1111/j.1365-2672.2008.03965.x · 2.48 Impact Factor
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ABSTRACT: Persistent contamination of surfaces by spores of Clostridium difficile is a major factor influencing the spread of C. difficile-associated diarrhoea (CDAD) in the clinical setting. In recent years, the antimicrobial efficacy of metal surfaces has been investigated against microorganisms including methicillin-resistant Staphylococcus aureus. This study compared the survival of C. difficile on stainless steel, a metal contact surface widely used in hospitals, and copper surfaces.
Antimicrobial efficacy was assessed using a carrier test method against dormant spores, germinating spores and vegetative cells of C. difficile (NCTC 11204 and ribotype 027) over a 3 h period in the presence and absence of organic matter.
Copper metal eliminated all vegetative cells of C. difficile within 30 min, compared with stainless steel which demonstrated no antimicrobial activity (P < 0.05). Copper significantly reduced the viability of spores of C. difficile exposed to the germinant (sodium taurocholate) in aerobic conditions within 60 min (P < 0.05) while achieving a >or=2.5 log reduction (99.8% reduction) at 3 h. Organic material did not reduce the antimicrobial efficacy of the copper surface (P > 0.05).
The use of copper surfaces within the clinical environment and application of a germination solution in infection control procedures may offer a novel way forward in eliminating C. difficile from contaminated surfaces and reducing CDAD.
Journal of Antimicrobial Chemotherapy 06/2008; 62(3):522-5. DOI:10.1093/jac/dkn219 · 5.31 Impact Factor
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ABSTRACT: Clostridium difficile is a major cause of hospital-associated infective diarrhea, and its spore form can persist for months in the hospital environment. Chlorine-based cleaning agents are recommended for eliminating this reservoir of potential infection.
To investigate the individual contributions of active chlorine, detergent and mechanical action on decontamination of a C difficile contaminated surface.
C difficile spores in test soil were dried onto stainless steel strips and exposed to sodium dichloroisocyanurate (NaDCC) or NaDCC combined with detergent (NaDCC+) or exposed to these cleaning formulations combined with wiping and/or detergent precleaning. After set contact times, remaining viable spores from the strips were recovered and enumerated by vortexing with glass beads, followed by membrane filtration.
Compared with NaDCC, the inclusion of detergent in the NaDCC+ formulation did not improve the effectiveness of decontamination in any exposure-only treatment at concentrations tested (P > .05). Combining wiping with exposure to the cleaning formulations improved decontamination effectiveness with further reductions in spore counts of 1.66- and 2.19-log(10) colony-forming units at 2 and 20 minutes, respectively, using NaDCC, and of 2.46 and 2.56 log(10) colony-forming units at 2 and 20 minutes, respectively, using NaDCC+. Precleaning the strips by wiping with detergent before exposure to NaDCC was more effective than wiping with NaDCC or NaDCC+ at 10 and 20 minutes contact times. Wiping with NaDCC+ was more effective than NaDCC only at a 2-minute contact time. Wiping with detergent followed by subsequent wiping with NaDCC (1,000 ppm) was the most effective treatment tested with a 4.00-log(10) reduction observed.
Rigorous precleaning with detergent and the associated physical removal of spores through the mechanical action associated with wiping are important factors in achieving effective decontamination of surfaces when using chlorine-based agents.
American journal of infection control 04/2011; 39(3):199-205. DOI:10.1016/j.ajic.2010.07.015 · 2.21 Impact Factor
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