Clinical features and in vitro susceptibilities of two varieties of Cryptococcus neoformans in Taiwan

One hundred years after introduction of the Eucalyptus tree to Taiwan, a pr edominantly subtropical island, we analyzed clinical and microbiological da ta of 59 patients with Cryptococcus neoformans infection hospitalized at Na tional Taiwan University Hospital during 1982 to 1997. There were 38 (64.4% ) cases of cryptococcosis caused by the var. neoformans and 21 (35.6%) caus ed by the var. gattii. Thirty-three patients (55.9%) had impaired T cell fu nction, which included 12 patients with acquired immunodeficiency syndrome (AIDS). Eleven of the 12 patients with AIDS were diagnosed after 1995, and 11 cases were caused by var. neoformans. Minimum inhibitory concentrations (MICs) determined by the NCCLS broth microdilution method using antibiotic medium 3 improved the discrimination of in vitro susceptibility against amp hotericin B and demonstrated that var, gattii isolates were less susceptibl e (geometric means 0.25 mu g/ml versus 0.64 mu g/ml, P < 0.001). In additio n, a higher proportion of var. gattii were less susceptible to flucytosine as compared with var. neoformans (35.0% versus 64.9%, P = 0.030). There was no seasonal clustering for isolation of var, neoformans, though infections caused by var. gattii peaked in July and August. Compared with the first s tudy of cryptococcosis (1957-1972) at NTUH, this study demonstrated the inc rease in immunocompromised and elderly patients, as well as a higher propor tion of Cryptococcus isolated from blood or bone marrow. Facing the increas ing adaptive plantation of Eucalyptus in Taiwan, the importance of field st udy regarding the role of Eucalyptus plantations in Taiwan and occurrence o f cryptococcosis in human beings cannot be over-emphasized. (C) 2000 Elsevi er Science Inc. All rights reserved.