Comparison of Biological Characteristics of Candida spp. Isolated in Japan, China, Italy and Peru

Abstract

A total of 214 Candida strains were isolated from the human oral cavity of normal subjects and patients with oral candidosis in Japan, China, Italy and Peru, and their morphological and biological characteristics were examined. All of the isolates were identified as Candida albicans by production of germ tubes and chlamydospores. To determine regional differences in biotypes, the isolates were subjected to biotyping by a killer yeast method. The 214 strains were grouped to 31 biotypes by their susceptibilities to the 24 killer yeasts. There were no clear regional differences in the biotypes. However, C. albicans strains isolated from patients showed diverse biotype distribution, as compared with isolates from normal subjects, suggesting changes in biotypes by treatment of oral candidosis. There were also no differences in production of extracellular proteinase and phospholipase, which are the most likely virulence factors, among strains isolated in different regions and subjects. The pathogenicity of a strong proteinase- and phospholipase-producing strain and a weak proteinase- and phospholipase-producing strain was compared in mice. The results obtained suggested the pathogenicity of the strains was related with the production of these enzymes.