Effects of broad-spectrum antibiotics on colonization of gastrointestinal tracts of mice by Candida albicans.

Three-month-old, male, Crl:CD1 (ICR) BR mice were fed chow containing Candida albicans or regular chow. Subsequently, both groups were given either antibiotics or normal saline for 10 days. Stool cultures were performed immediately before administration, at the end of antibiotic administration, and 1 week after the discontinuation of antibiotics, to determine the effect on the concentration of C. albicans in the stools. The stools of mice fed C. albicans and given antibiotics had substantially higher Candida counts than those of control mice fed C. albicans and given saline. Significantly higher candidal concentrations were observed in the stools of mice given chloramphenicol compared with those of mice given ciprofloxacin, sulfamethoxazole-trimethoprim, and ampicillin. No mice developed histopathological evidence of local gastrointestinal invasion or disseminated candidiasis. In this mouse model, Candida colonization increases substantially after the administration of antimicrobial agents with broad spectra and anaerobic activities.