Production of germ tubes by virulent and attenuated strains of Candida albicans

Two strains (no. 19321 and no. 19273) of Candida albicans that were obtained from patients with vaginal thrush and were virulent for mice formed germ tubes after incubation in fresh mouse serum and mouse kidney extract more rapidly and to a greater extent than did two strains (no. 22114 and no. 21462) that were isolated from patients with transient candidemia and were attenuated for mice. After incubation in fresh human serum, the strain differences in germination were not as marked although the pattern was similar. Synchronous cultures of strains no. 19321 and no. 22114 showed differences similar to those shown by asynchronous cultures in the mouse and human sera and in the mouse kidney extract. The viability of the strains was maintained in all three types of media; thus, nonspecific humoral defense mechanisms had little effect on the attenuated strain.