GASTRIC COLONIZATION WITH CANDIDA-ALBICANS

We adapted a rat model of gastrointestinal candidiasis for studies of in vivo gastric colonization with Candida albicans. Whereas normal rat s cleared a single intragastric inoculum of 5 X 10(6) C. albicans from the stomach within 4 hours, rats pretreated with chloramphenicol and gentamicin achieved stable gastric colonization for at least 5 days af ter administration of this inoculum. We next used this model to study host modifications hypothesized to alter gastric colonization. A first group received dilute HCl 4 hr before yeast inoculation, to induce ac ute superficial gastric erosions; another group was treated with gluco corticosteroid beginning 12 days before yeast inoculation; and another group received famotidine therapy beginning 3 days before yeast inocu lation, to neutralize gastric acidity. Recovery of yeasts from stomach s was significantly different from the control group only in rats trea ted with steroids; greater colonization was found in the rats so treat ed. In a final group of experiments, we attempted to inhibit in vivo g astric colonization with yeasts by preincubation of yeasts in vitro wi th a polyclonal antiserum raised in rabbits against heat-killed C. alb icans. We were not able to demonstrate inhibition of gastric colonizat ion by preincubation with this antiserum in this model system.