Speciation of fecal Candida isolates in antibiotic-associated diarrhea in non-HIV patients.

Candida is the most frequently encountered fungal infection of the gastrointestinal tract after antibiotic exposure. The pathogenesis of Candida probably varies with each species. The speciation of fecal Candida after antibiotic use is not well investigated. One hundred and eleven fecal samples negative for Clostridium difficile toxin and for other enteric pathogens formed the basis of our investigation. The diarrheic samples came from patients receiving antibiotics in a hospital setting. In addition, samples from 30 age-matched healthy participants who did not receive antibiotics and did not have diarrhea were also studied. Initially, a Gram stain identification for yeasts was performed for each fecal sample, then each sample was cultured on Sabouraud's dextrose agar. Candida was isolated as pure growth (>10(5) cfu/ml) from the stools of 32 (28.8%) patients. The identification of the yeast was done based upon a combination of morphological, physiological and biochemical criteria. The predominant isolates were C. tropicalis (n=16), C. albicans (n=14) and C. krusei (n=2). Candida isolated from healthy participants (n=4) was sparse and therefore not speciated. Different Candida spp. may play an important role in precipitating antibiotic-associated diarrhea.