Ceftriaxone and dexamethasone affecting yeast gut flora in experimental mice.

Crl:CD1 (ICR) BR mice were fed regular food or food containing Candida albicans to induce gastrointestinal (GI) colonization by the yeast. Groups of colonized mice were subsequently treated with either ceftriaxone for 10 days or dexamethasone for 10 or 21 days. Another group of colonized mice was treated with the combination of ceftriaxone, given for 10 days, and dexamethasone given for 21 days. Other colonized mice received normal saline, and non-colonized mice received the same drugs or saline, serving as controls. Candida-colonized mice, treated either with ceftriaxone or with dexamethasone alone, had significantly increased levels of GI colonization by the yeast. Colonized mice treated with the combination of the antibiotic with dexamethasone had stool concentrations of Candida similar to those of mice treated with the antibiotic alone. Saline did not affect Candida stool concentration. Yeasts were not found in the stools of non-colonized mice treated with the study drugs or saline. There was no evidence of Candida dissemination to internal organs in any group.