MOLECULAR TYPING OF CRYPTOCOCCUS-NEOFORMANS - TAXONOMIC AND EPIDEMIOLOGIC ASPECTS

Pulsed-field gel electrophoresis (PFGE), randomly amplified polymorphi c DNA (RAPD) analysis, serotype, and killer toxin sensitivity patterns of a wide range of saprobic, clinical, and veterinary isolates of bot h varieties of Cryptacoccus neoformans were examined. C. neoformans va r. neoformans and C, neoformans var. gattii differed in chromosomal ma keup, RAPD patterns, and killer sensitivity patterns. These results su ggest that there are two separate species rather than two varieties. N o clear genetic or phenotypic differences were observed among the clin ical, saprobic, and veterinary isolates within each taxon. The serotyp es differed substantially in their RAPD characteristics. Geographical clustering was observed among the isolates of C. neoformans var. gatti i, but not among the isolates of C. neoformans var. neoformans. The is olates of each taxon that originated from restricted geographical area s often had identical or similar karyotypes and RAPD patterns, suggest ing that clonal reproduction had occurred. The combination of PFGE and RAPD analysis allowed us to distinguish almost all isolates. This com bination of techniques is recommended for further research an epidemio logical, ecological, and population issues.