Ceftriaxone and dexamethasone affecting yeast gut flora in experimental mice

Crl:CD1 (ICR) BR mice were fed regular food or food containing Candida albi cans to induce gastrointestinal (GI) colonization by the yeast. Groups of c olonized mice were subsequently treated with either ceftriaxone for 10 days or dexamethasone for 10 or 21 days. Another group of colonized mice was tr eated with the combination of ceftriaxone, given for 10 days, and dexametha sone given for 21 days. Other colonized mice received normal saline, and no ncolonized mice received the same drugs or saline, serving as controls. Can dida-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 dexameth asone had stool concentrations of Candida similar to those of mice treated with the antibiotic alone. Saline did not affect Candida stool concentratio n. Yeasts were not found in the stools of non-colonized mice treated with t he study drugs or saline. There was no evidence of Candida dissemination to internal organs in any group.