Yeasts isolated from oral cavity of the healthy adults

Kim, Young Ah; Cho, Dong Hee; Lee, Kyungwon; Chong, Yunsop; Kwon, Ho Kwen

Abstract

BACKGROUND: Interpretation of yeast isolation from sputum is problematic due to contamination of yeasts in the oral cavity. Knowledge on the yeast colonization of normal oral cavity is necessary for the interpretation of yeast isolation. We determined the isolation rate, count and persistence of yeasts in oral cavity of the healthy adults.
METHODS
Seven weekly specimens of saliva were collected from 40 healthy adults during September to December, 1998. They were quantitatively cultured in selective Sabouraud dextrose agar containing antibiotics. The yeast colonies were counted and species identified by Vitek YBC card. The persistence of yeasts were determined by comparing the weekly culture.
RESULTS
Yeasts were isolated from 77.5% of the subjects at least once. The yeasts isolated were nine Candida species, three Cryptococcus species and three other yeasts. C. albicans was found in 30.0% of 40 subjects and 22.5% of 240 samples. The count ranged from 1 to 3,960 CFU/mL. C. albicans and C. parapsilosis were relatively more frequently isolated and the mean numbers were 226 CFU/mL and 84 CFU/mL, respectively. C. albicans was persistently recovered yeast at successive cultures but other species except C. parapsilosis were isolated only one or two times.
CONCLUSIONS
Large number of C. albicans colonize in oral cavity of some healthy adults persistently. The clinical significance of isolated yeasts from sputum specimen which can be mixed with oral flora should be interpreted cautiously on the basis of underlying disease, symptom and X-ray finding of the patient, together with the isolated species, count, and persistence of the yeasts.