Comparison of seven phenotyping methods for Candida albicans

Seven different phenotyping methods for strain differentiation of Candida albicans (auxonotyping, enzymotyping, resistotyping, Phongpaichit's morphotyping, Hunter's morphotyping and Odds and Abbott's biotyping method-1980 and 1983 versions) were compared on a single population of 94 strains. 77.6% of the strains belonged to auxonotyping 1, 59.6% to enzymotyping A, 34% to resistotyping B and 30.8% to BC, 40.4% to Phongpaichit's morphotyping 000,000 and 40.4% to Hunter's morphotyping 'No fringe/Smooth surface'. Using biotyping systems (1980 and 1983 versions), the most frequent biotypes were 145 (29.8%) and 147 (31.9%) respectively. The Discriminatory Index of Hunter and Gaston was employed to carry out comparisons among the different systems. The best discriminatory results, although far from ideal, were found using Phongpaichit's morphotyping (DI = 0.827) and Odds and Abbott's method (DI = 0.815 and 0.831--1980 and 1983 versions). A good discriminatory result was also found using Hunter's morphotyping method together with the biotyping of Odds and Abbott (1983 version). These approximated the ideal (DI = 0.950) and showed minimal difficulty in interpretation. The proposed combined method revealed high discrimination among the vulvovaginal strains, and suggested the absence of transmissible pathogenic strains.