Mating types and serotypes of Cryptococcus neoformans isolated in Japan.

Thirty-two isolates of Cryptococcus neoformans from patients and one from the wild obtained in Japan were characterized for their serotype, self-fertility, and mating behaviour by crossing them with two mating types of Filobasidiella neoformans var. neoformans and F. neoformans var. bacillispora. Of the 32 isolates from patients, 31 were of serotype A and the remaining one was of serotype D. Although these 32 isolates were all self-sterile, 23 serotype A and one serotype D isolates produced a complete sexual state when mixed with the alpha mating type of F. neoformans var. neoformans. The one natural isolate was of serotype A-D and self-fertile. The Japanese clinical isolates of C. neoformans appear to be predominantly serotype A and alpha mating type of F. neoformans var. neoformans as is the case in the U.S.A.