DNA relatedness among the three varieties of Cryptococcus albidus.

Cryptococcus albidus (Saito) Skinner var. albidus 1922 and C. albidus (Saito) Skinner var. aerius (Saito) Phaff et Fell 1970 were first isolated from the air by Saito in 1922 (16). They were then described as Torula albida and Torula aeria, respectively. Phaff and Fell (12) separated the lactose-negative variety albidus strains as C. albidus (Saito) Skinner var. diffluens (Zach) Phaff et Fell 1970 from C. albidus var. albidus. However, Rodrigues de Miranda (15) rejected C. albidus var. dif fluens because it appeared to be impossible to make a sharp distinction by lactose assimilation; some strains classified as C. albidus var. albidus assimilated lactose very weakly or not at all, and some strains of C. albidus var. diffluens assimilated lactose strongly and some only weakly. C. albidus var. aerius is distinguishable from C. albidus var. albidus by the absence of starch production. At present, only var. albidus and var. aerius are maintained (15). Shinoda et al. (17) suggested that proton magnetic resonance spectra ('H-NMR) of cryptococcal capsular polysaccharides would be useful for the classification of Cryptococcus species. They stated that C. albidus var. albidus and C. albidus var. diffluens belonged to different subgroups based on the spectral patterns of their H-1 region. In addition, Ikeda et al. (2) demonstrated that the three varieties of C. albidus were clearly divided into different serological groups by slide agglutination tests with eight factor sera.