Effect of various diets on toxin production by two strains of Clostridium difficile in gnotobiotic mice

Abstract

When axenic mice fed a commercial diet were monoassociated with two toxigenic strains of Clostridium difficile, 100% of them died 3 days after inoculation and both enterotoxin and cytotoxin were produced in their intestinal tract. However, when axenic mice were fed various semisynthetic diets before C. difficile challenge, some of them survived and their fecal cytotoxin and enterotoxin productions were highly reduced, whereas the C. difficile population level did not decrease to a great extent. Thus, gnotobiotic mice associated with C. difficile were a good model for the study of modulation by the dietary regimen of intestinal cytotoxin and enterotoxin production.

Fixation of Clostridium difficile toxin A and cholera toxin to intestinal brush border membranes from axenic and conventional mice

“…Toxin A used in the test (produced by C. difficile) was crude. It was obtained from dialysis cultures of C. difficile as previously described (17) and stored at -20°C until use. Cholera toxin was purchased from Sigma Chemical Co., St. Louis, Mo.…”

“…Toxin A quantities were determined by using an enzymelinked immunosorbent assay (ELISA) procedure previously described (17). Only toxin A is revealed by this test.…”

“…All binding reactions were run in triplicate. The supernatants containing the residual toxin not fixed to the membranes were quantitated by using an ELISA previously described (17). To increase the precision of the ELISA for residual toxins, and in order to be in the linear portion of the reference curve, three dilutions of each sample were performed.…”

“…Patients treated with antibiotics, however, are especially at risk for this infection. The infection can be experimentally produced by inoculating clindamycin-treated hamsters (2,4,8,19) or axenic mice (5,17) with C. difficile, and these two models have contributed much to the comprehension of C. diffic ileassociated pathology. Toxin A (enterotoxin) is recognized to be highly important in the pathological process by inducing water loss (15,18,20).…”

Modeling host–pathogen interactions: H. sapiens as a host and C. difficile as a pathogen

“…Genetic and biochemical evidences have shown that TcdC interferes with TcdR‐containing RNA polymerase and thus inhibits C. difficile toxin synthesis (Voth and Ballard, ; Matamouros et al ., ). Further details on toxin effects on infected host can be found in Burdon et al ., (), Mahe et al ., (), McFarland et al ., (), Ward and Young () and Akerlund et al ., ().…”