Antibiotics affecting gastrointestinal colonization of mice by yeasts.

A group of three-month old, male Crl:CD1(ICR) BR mice, was fed chow containing Candida albicans, while another group of the same type of mice was fed regular chow. Both groups were treated subsequently with either antibiotics or normal saline for 10 days. Stool cultures were performed before treatment, at the end of treatment, and one week after the end of treatment, to determine the level of colonization of the gastrointestinal tract by the yeast. The stools of mice fed Candida and treated with antibiotics had substantially higher Candida counts than control mice fed C. albicans and treated with saline. The highest concentrations of the yeast were observed in the stools of mice treated with cefotaxime as compared to those of mice treated with pefloxacin, amikacin and amoxicillin. No Candida was found in the stools of mice fed regular chow and treated with antibiotics or saline. Dissemination of Candida was not observed in the visceral organs of any mouse.