Improved isolation of Clostridium perfringens from foal faeces

There have been several case reports of foal diarrhoea associated with Clostridium perfringens. However, there has been no epidemiological assessment of the strength of the association of these bacteria with foal diarrhoea or of their relative importance. To prepare methods for such a study, the success of different cultural techniques for the isolation of C perfringens was examined with respect to the various physiological states of the bacteria. The germination and growth of C perfringens NCTC 8239 endospores of differing maturity were favoured by different pre-treatments which failed to recover vegetative cells or endospores of C perfringens NCTC 8237. Faecal samples from 271 foals were used to test the hypothesis that the recovery of C perfringens, probably present in different states ranging between vegetative cell and germinating endospore, would be improved by using several methods in parallel. Five methods (two pre-enrichment and three direct), using different pre-treatments with heat, ethanol and EDTA, or no pre-treatment, together isolated C perfringens from 64 per cent of the samples; the most sensitive method (which isolated the most C perfringens) detected only 74 per cent of these positive samples. All the methods detected C perfringens in at least one sample from which it was not isolated by any other method. It was concluded that several methods used in combination on each sample would be required to evaluate fully any epidemiological association between C perfringens and foal diarrhoea.