Biotypes, genotypes and ketoconazole susceptibility of Candida albicans isolates from a group of Thai AIDS patients

A total of eighty-seven Candida albicans isolates from a group of Thai AIDS patients were characterized for phenotypic and genotypic profiles and antifungal susceptibility to ketoconazole. Phenotyping of the isolates was carried out by a biotyping method based on the enzyme profiles, carbohydrate assimilation patterns and boric acid resistance of the yeasts. Genotyping was performed through randomly amplified polymorphic DNA (RAPD) analysis. Antifungal susceptibility of ketoconazole was performed using the NCCLS broth microdilution method. Combination of the biotypic tests revealed a total of 49 different biotypes. The most predominant was A1S (31%), the remaining biotypes represented only few isolates in each. RAPD profiles identified 14 clusters of genotype among the 87 isolates. Almost every individual harboured his/her own specific isolate and in 25 of 26 (96.2%) harboured more than one clonal type. The heterogeneity of both phenotypic and genotypic profiles of C. albicans isolates in this study was similar to previous reports from other oral sources in different geographic areas. All isolates were susceptible to ketoconazole. The findings may be useful as baseline information of oral C. albicans colonization in Thai population living in the south of Thailand.