| Previous studies have shown a high incidence (45%—59%) of isolation of Candida spp. from the oral cavities in the elderly. So far, no studies about the incidence of Candida spp. in the elderly, the affecting factors of the incidence of Candida spp. and the genetic relatedness of C.albicans with the incidence of the C.albicans in elderly have been performed. Therefore the aim of this study is to investigate the frequency and intensity of oral Candida spp. in elderly in Chengdu, then to study the role of sex, denture-wearing and dentition in the distribution of Candida spp. in elderly. After this, we continue to study the genotypic profiles of C.albicans isolated from the elderly in Chengdu and compare the relationship of the incidence of C.albicans with the genotype of C.albicans. In addition, C.albicans of the different genotypes was comparing the adherence ability and biofilms formation ability in vitro by adherence assays and XTT reduction assays, for the purpose to obtain the relationship of the biological characteristics of oral C.albicans with thegenetic characteristics of oral C.albicans in elderly. This study will enrich the molecular epidemic knowledge of C.albicans and this project will play an important role in prophylaxis candidiasis in elderly individuals.A total of 232 individuals (age, >60 years) was divided into five groups: A1 (48 man with dentures), Bl (61 man without dentures), A2 (53 women with dentures), B2 (50 women without dentures) and C (20 man without dentition). Oral rinse samples were centrifuged, resuspended in PBS, and plated onto Sabouraud's dextrose agar and CHROMagar Candida?. CHROMagar Candida?, Sugar assimilation patterns (API 20C AUX tests) were used to identify Candida spp., and RAPD (randomly amplified polymorphic DNA) assays were used to determine C.albicans. The total number of yeast colonies on the plate was considered the relative intensity of oral carriage. C.albicans was screened for genotypic profiles by RAPD assays, two different primers (JWFF and NA) were used to develop DNA profiles. The biological characteristics such as adherence ability and biofilms formation ability of the different genotype of C.albicans were compared by adherence assays and by XTT reduction method, respectively.Candida spp. was isolated from 232 healthy elderly individuals (52.1%), such as C. albicans, C. parapsilosis, C. krusei, C. guilliermondii, C. tropicalis, etc. The frequency of Candida spp. of Al, Bl, A2, B2 and C is 66.7%, 36.1%, 64.1%, 56% and 25%, respectively. The frequency of C. albicans of Al, Bl, A2, B2 and C is 56.2%, 21.3%, 56.6%, 38% and 10%, respectively. The difference of the frequency of Candida spp. between Al and A2 was significant (P=0.036). The difference of the frequency of Candida albicans between A1 and A2 was significant (P=0.043). The difference of thefrequency of Candida spp. and C. albicans between Al and Bl were significant (F<0.002), respectively. The difference of the frequency of Candida spp. and C. albicans between Al and C were significant (PO.005), respectively. The intensity of Candida spp. and the proportion of individuals with Candida spp. in the highest range were greater for individuals in denture-wearing groups than the controls. RAPD analyses with random primers JWFF and NA revealed 5 different genotypes (A-E) among C. albicans, type A and type B are the dominating genotypes of the C. albicans. There was significant difference in the genotypic constitution between group Al and Bl (PO.01). Statistically, in group Al the major type was A. There was no significant difference of adherence ability and biofilms formation ability of the different genotype of C. albicans in vitro.By doing this study, we get some finding. First, the frequency and intensity of Candida spp. increased in elderly. Second, the frequency of Candida spp. in elderly are correlated with sex; the frequency and intensity of Candida spp. in elderly are closely correlated with denture-wearing; and the difference in frequency and intensity of yeast is due to the difference in frequency and intensity of C.albicans. Third, the genotypic profiles of the C.albicans of the male elderly are closely correlated with denture-wearing. Denture-wearing may contribute to the increasing frequency of some C albicans isolates with special genotypic profiles in elderly.
|
PDF Full Text Request