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Clostridium difficile is a major enteropathogen of humans. It produces two main virulence factors, toxins A and B. A third, less well known toxin, C. difficile toxin (CDT), is a binary toxin composed of distinct enzymatic (CdtA) and cell binding/translocation (CdtB) proteins. We used a novel enzyme linked immunoassay (EIA) to detect CdtB protein in feces and culture fluids. Additionally, PCR was used to assay C. difficile isolates from fecal samples for the CDT locus (CdtLoc). Although the results from 80 isolates suggest no relationship between toxin concentrations in situ and in vitro, there is a good correlation between PCR detection of the cdtB gene and EIA detection of CdtB protein in vitro. Possible implications of the detection of CDT in patients are discussed., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

We investigated the frequency of Clostridium perfringens in the normal fecal flora of healthy North Americans. About half of 43 subjects were colonized with C. perfringens at levels of approximately 10(6)cfu/g feces. Only type A strains were recovered. Spores sometimes outnumbered vegetative cells. Several genotypes were found. Some donors carried two genotypes, some only one. We found no alpha, beta2 or enterotoxin in the stools of any donors. Though some isolates carried toxin genes (e.g. cpe and cpb2) on plasmids, we saw no indication that healthy humans are the reservoir for the chromosomally-borne cpe recovered from cases of C. perfringens food poisoning.