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SJBird55 -> RE: c. difficile (April 13, 2008 3:26:05 PM)
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For products that are effective for c. difficile vegetative bacterium: http://www.epa.gov/oppad001/list_i_clostridium.pdf
Much more difficult to kill the spores. Apparently there are no EPA approved products for the spores. The CDC recommends a hypochlorite based product (bleach). http://www.cdc.gov/ncidod/dhqp/id_CdiffFAQ_hcp.html#10
Infect Control Hosp Epidemiol. 2007 Aug;28(8):920-5. Epub 2007 Jun 15.
Efficacy of hospital cleaning agents and germicides against epidemic Clostridium difficile strains.
Fawley WN, Underwood S, Freeman J, Baines SD, Saxton K, Stephenson K, Owens RC Jr, Wilcox MH.Department of Microbiology, General Infirmary, Old Medical School, Leeds, United Kingdom.
OBJECTIVE: To compare the effects of hospital cleaning agents and germicides on the survival of epidemic Clostridium difficile strains. METHODS: We compared the activity of and effects of exposure to 5 cleaning agents and/or germicides (3 containing chlorine, 1 containing only detergent, and 1 containing hydrogen peroxide) on vegetative and spore forms of epidemic and non-epidemic C. difficile strains (3 of each). We carried out in vitro exposure experiments using a human fecal emulsion to mimic conditions found in situ. RESULTS: Cleaning agent and germicide exposure experiments yielded very different results for C. difficile vegetative cells, compared with those for spores. Working-strength concentrations of all of the agents inhibited the growth of C. difficile in culture. However, when used at recommended working concentrations, only chlorine-based germicides were able to inactivate C. difficile spores. C. difficile epidemic strains had a greater sporulation rate than nonepidemic strains. The mean sporulation rate, expressed as the proportion of a cell population that is in spore form, was 13% for all strains not exposed to any cleaning agent or germicide, and it was significantly increased by exposure to cleaning agents or germicides containing detergent alone (34%), a combination of detergent and hypochlorite (24%), or hydrogen peroxide (33%). By contrast, the mean sporulation rate did not change substantially after exposure to germicides containing either a combination of detergent and dichloroisocyanurate (9%) or dichloroisocyanurate alone (15%). CONCLUSIONS: These results highlight differences in the activity of cleaning agents and germicides against C. difficile spores and the potential for some of these products to promote sporulation.
Lancet. 2000 Oct 14;356(9238):1324.
Comment in:
Lancet. 2000 Dec 16;356(9247):2098-9.
Hospital disinfectants and spore formation by Clostridium difficile.
Wilcox MH, Fawley WN.Evidence is lacking on how best to decontaminate the hospital environment of Clostridium difficile. We compared sporulation levels in the UK epidemic C. difficile strain (P24), another clinical isolate (B31), and an environmental strain (E4) cultured in faecal emulsion containing subinhibitory concentrations of one of five hospital cleaning agents. The epidemic strain produced significantly more spores than the non-prevalent strains, and sporulation was further enhanced when this strain was cultured in faeces exposed to non-chlorine-based cleaning agents. The choice of cleaning agent can have a substantial effect on the persistence of C. difficile spores in the hospital environment.
Infect Control Hosp Epidemiol. 2003 Oct;24(10):765-8.
Activity of three disinfectants and acidified nitrite against Clostridium difficile spores.
Wullt M, Odenholt I, Walder M.Department of Infectious Diseases, Lund University, Malmö University Hospital, Malmö, Sweden.
OBJECTIVE: To identify environmentally safe, rapidly acting agents for killing spores of Clostridium difficile in the hospital environment. DESIGN: Three classic disinfectants (2% glutaraldehyde, 1.6% peracetyl ions, and 70% isopropanol) and acidified nitrite were compared for activity against C. difficile spores. Four strains of C. difficile belonging to different serogroups were tested using a dilution-neutralization method according to preliminary European Standard prEN 14347. For peracetyl ions and acidified nitrite, the subjective cleaning effect and the sporicidal activity was also tested in the presence of organic load. RESULTS: Peracetyl ions were highly sporicidal and yielded a minimum 4 log10 reduction of germinating spores already at short exposure times, independent of organic load conditions. Isopropanol 70% showed low or no inactivation at all exposure times, whereas glutaraldehyde and acidified nitrite each resulted in an increasing inactivation factor (IF) over time, from an IF greater than 1.4 at 5 minutes of exposure time to greater than 4.1 at 30 minutes. Soiling conditions did not influence the effect of acidified nitrite. There was no difference in the IF among the 4 strains tested for any of the investigated agents. Acidified nitrite demonstrated a good subjective cleaning effect and peracetyl ions demonstrated a satisfactory effect. CONCLUSIONS: Cidal activity was shown against C. difficile spores by glutaraldehyde, peracetyl ions, and acidified nitrite. As acidified nitrite and peracetyl ions are considered to be environmentally safe chemicals, these agents seem well suited for the disinfection of C. difficile spores in the hospital environment.
Am J Infect Control. 2005 Aug;33(6):320-5.
Activity of selected oxidizing microbicides against the spores of Clostridium difficile: relevance to environmental control.
Perez J, Springthorpe VS, Sattar SA.Centre for Research on Environmental Microbiology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
BACKGROUND: Clostridium difficile is an increasingly common nosocomial pathogen, and its spores are resistant to common environmental surface disinfectants. Many high-level disinfectants (eg, aldehydes) are unsuitable for environmental decontamination because they need several hours of contact to be sporicidal. This study tested the potential of selected oxidative microbicides to inactivate C. difficile spores on hard surfaces in relatively short contact times at room temperature. METHODS: The spores of a clinical isolate of C. difficile were tested using disks (1 cm diameter) of brushed stainless steel in a quantitative carrier test. The spores of C. sporogenes and Bacillus subtilis, common surrogates for evaluating sporicides, were included for comparison. The clostridia were grown separately in Columbia broth (CB), and B. subtilis was grown in a 1:10 dilution of CB. Each disk received 10 microL test spores with an added soil load, and the inoculum was dried. One disk each was placed in a glass vial and overlaid with 50 microL test formulation; controls received an equivalent volume of normal saline with 0.1% Tween 80. At the end of the contact time the microbicide was neutralized, the inoculum recovered from the disks by vortexing, the eluates were membrane filtered, and the filters placed on plates of recovery medium. The colony-forming units (CFU) on the plates were recorded after 5 days of incubation. The performance criterion was > or = 6 log(10) (> or = 99.9999%) reduction in the viability titer of the spores. The microbicides tested were domestic bleach with free-chlorine (FC) levels of 1000, 3000, and 5000 mg/L; an accelerated hydrogen peroxide (AHP)-based product with 70,000 mg/L H2O2 (Virox STF); chlorine dioxide (600 mg/L FC); and acidified domestic bleach (5000 mg/L FC). RESULTS: Acidified bleach and the highest concentration of regular bleach tested could inactivate all the spores in < or = 10 minutes; Virox STF could do the same in < or = 13 minutes. Regular bleach with 3000 mg/L FC required up to 20 minutes to reduce the viability of the all the spores tested to undetectable levels; chlorine dioxide and the lowest concentration of regular bleach tested needed approximately 30 minutes for the same level of activity. CONCLUSIONS: Acidified bleach, Virox STF, and regular bleach (3000-5000 mg/L FC) could inactivate C. difficile spores on hard environmental surfaces in approximately 10 to 15 minutes under ambient conditions. All of these products are strong oxidizers and should be handled with care for protection of staff, but acidified and regular bleach with high levels of FC also release chlorine gas, which can be hazardous if inhaled by staff or patients.
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