Candida glabrata, an emerging fungal pathogen, exhibits superior relative cell surface hydrophobicity and adhesion to denture acrylic surfaces compared with Candida albicans

Abstract

Oral candidosis is a common opportunistic infection in debilitated individuals and Candida glabrata is the second most frequently isolated species from this condition, after Candida albicans. Candidal adherence to various biological or non-biological surfaces is considered a prerequisite for colonization, and pathogenesis of candidal infections, and their relative cell surface hydrophobicity (CSH) is likely to be a possible contributory force involved in this process. Whereas a large body of data on the latter features of C. albicans is available, there is surprisingly little information on C. glabrata. As a comprehensive database on the relative adhesion and CSH of Candida spp. is instructive and useful, we investigated in vitro the latter attributes of 34 oral isolates of C. glabrata and 15 isolates of C. albicans. There were remarkable intraspecies differences in both the CSH and the adhesive ability of C. glabrata strains (p<0.001). Compared with C. albicans, C. glabrata demonstrated a four-fold greater CSH value (30.63±11.20% vs 7.23±3.56%, p<0.0001) and a two-fold greater tendency to adhere to denture acrylic surfaces (75.18±39.96 vs 30.36±9.21, p<0.0001). A significant positive correlation between CSH and adhesion was also noted for both C. glabrata (r=0.674, p<0.0001) and C. albicans (r=0.636, p<0.05). When the effect of different incubation conditions on the relative CSH and adherence of C. glabrata was examined, CSH and the adherence to acrylic surfaces of four of six C. glabrata isolates were significantly affected by a reduction of the culture temperature (from 37°C to 25°C). A positive relationship also emerged when the temperature-induced variations in the adherence values were correlated with their relative CSH. These data provide hitherto unavailable archival information on important pathogenic attributes of the two most common oral Candida species that may help explain their predominance in this milieu.