Distribution of Candida albicans in the oral cavity of children aged 3-5 years of Uygur and Han nationality and their genotype in caries-active groups.

We analyzed the distribution of Candida albicans in the oral cavity of 3-5-year-old children of Uygur and Han nationalities as well as their genotypes in caries-active groups in the Urumqi municipality. CHROMagar Candida was separately cultivated, and we identified 359 Uygur and Han children aged 3-5 years. We randomly selected 20 Han children and 20 Uygur children for this study. We chose a bacterial strain for polymerase chain reaction (PCR) 25S rDNA genotyping and random amplified polymorphic DNA (RAPD) genotyping. The rate of caries-active in Han children was higher than that in Uygur children, with values of 39.6 and 24.3%, respectively. The detection rate of C. albicans was closely correlated to the caries filling index classification (X(2) = 31.037, P = 0.000, r = 0.421; X(2) = 80.454, P = 0.000, r = 0.497). PCR of 25S rDNA from 40 strains of Han and Uygur children revealed 3 genotypes, while RAPD analysis revealed 5 genotypes. The distribution of 25S rDNA genotyping of Han children from PCR differed from that of Uygur children (X(2) = 7.697, P = 0.021), both of which were mainly the A type. RAPD genotyping of both Han and Uygur children showed similar results (X(2) = 1.573, P = 0.814). There were differences in the distributions of C. albicans in children of different nationalities. C. albicans is a key factor causing caries. The PCR 25S rDNA genotyping method is simple and sensitive, while the RAPD genotyping method is reliable and comprehensive.