Gastrointestinal candidiasis in rats treated with antibiotics, cortisone, and azathioprine.

Conventional albino rats treated with peroral chloramphenicol, gentamicin, and/or parenteral cortisone were challenged with Candida albicans Antibiotics and cortisone were equally effective in predisposing the animals to colonization by the fungus. All animals treated with both antibiotics and cortisone developed defined, focal, superficial invasion of the cornified squamous epithelium of the stomach next to its junction with the glandular mucosa, as well as focal superficial invasion of the esophagus. Equivalent yeast cell and mycelial inocula of C. albicans were equally effective in producing colonization and invasion of the gut. Dissemination of the fungus from the gut was not found even after the addition of azathioprine to the treatment regimen; however, such addition did predispose to more extensive and severe lesions of the esophagus and stomach. Approximately 25% of infected cortisone- and antibiotic-treated rats developed agglutinins against C. albicans by 22 to 23 days after challenge, whereas 15% developed precipitins. The antibiotic-cortisone-treated rat may be a useful and consistent experimental model in the study of gastrointestinal candidiasis.