Recovery of spores of Clostridium difficile altered by heat or alkali

Abstract

Summary. The effect of heating or alkali-treatment on spore recovery in ordinary growth medium was examined for four strains of Clostridium dificile. Heating spores at 80°C for 10 min produced 95-50-99-95% decreases in the recovery rates. Treatment with 0.1 N NaOH for 15 rnin produced 99-47 and 99.83% decreases in spore recovery rates for two of the four strains. The influence of either addition of lysozyme after treatment with sodium thioglycollate (thioglycollate-lysozyme method) or addition of sodium taurocholate (taurocholate method) on recovery of heat-or alkali-treated C. dificile spores was also examined. Viable spores of all strains altered by heating at 90°C or 100°C for 10 min could not be recovered at all by the taurocholate method. Nor did this method allow recovery of alkali-altered spores treated with >0-2 N NaOH for 15 min. On the other hand, 10-47% of altered spores heated at 90°C for 10 min were recovered by the thioglycollate-lysozyme method, and alkali-altered spores treated with 0.1-0.3 N NaOH for 15 min were as completely recovered by this method as untreated spores. These results indicate that the thioglycollate-lysozyme method is more effective than the taurocholate method for recovery of the heat-or alkali-altered C. dificile spores.

Bile Salts and Glycine as Cogerminants for Clostridium difficile Spores

“…The only other known approach to inducing germination of C. difficile in the laboratory is to treat spores with high concentrations of a reducing agent and lysozyme (16). This method of germination is not likely to be biologically relevant.…”

“…Previous work showed that taurocholate, a bile salt, enhances colony formation by C. difficile spores recovered from environmental surfaces and stool (2,40,44). Similarly, treatment of C. difficile spores with lysozyme and thioglycolate enhances colony formation (16,43). These effects on colony formation are clear, but it is difficult to discern what specific effects the treatments might have on germination.…”

Inhibiting the Initiation ofClostridium difficileSpore Germination using Analogs of Chenodeoxycholic Acid, a Bile Acid

“…The germination receptors that C. difficile uses to sense the environment have not been identified. Based on homology searches, C. difficile germination receptors must be very different from known germination receptors (42), but they appear to be proteinaceous (13).…”

Clostridium difficile infection: A critical overview

“…C. difficile spores are stable at temperatures ranging from -20°C to 90°C [35]; they are resistant to desiccation [11•] and are only destroyed by high heat or alkaline pH [36]. A variety of cleaning agents are effective in killing the vegetative forms of C. difficile, but only chlorine-based disinfectants and high concentrations of vaporized hydrogen peroxide have been shown to be sporicidal [37].…”