Cryptococcus neoformans varieties as agents of cryptococcosis in Brazil

Abstract

The study of the clinical isolates of Cryptococcus neoformans from 83 Brazilian patients with disseminated cryptococcosis showed that 75 were C. neoformans var. neoformans and 8 were var. gattii. Twenty-seven isolates were serotyped; all 19 var. neoformans were serotype A and all 8 var. gattii were serotype B. The correlation of the varieties of C. neoformans with the presence or not of hosts predisposing conditions to the mycosis showed that: (1) cryptococcosis caused by gattii variety occurred in 7 (58.3%) of the 12 nonimmunosuppressed patients, and (2) cryptococcosis caused by neoformans variety occurred in 65 (98.5%) of the 66 AIDS patients and in all 5 patients with other immunosuppressive conditions. The comparison of the distribution of the gattii and neoformans varieties between the nonimmunosuppressed and immunosuppressed patients showed a significant statistical difference (p < 0.01).

PIP: 8 mycologists reviewed the medical records of 83 patients with disseminated crypttococcosis living in Brazil to examine the varieties of Cryptococcus neoformans. 12 patients were not immunosuppressed (group 1). 65 patients had AIDS (group 2). 5 patients either also had another disease and/or used immunosuppressive drugs (group 3). Almost all the clinical isolates were from the cerebrospinal fluid and/or blood (80 isolates [96.4%]. C. neoformans var. gattii caused cryotococcosis in 58.3% (7) of the nonimmunosuppressed patients. C. neoformans var. neoformans was responsible for crypttococcosis in all but 1 of the AIDS patients (98.5%) and in all 5 patients who had another disease and/or used immunosuppressive drugs. 6 of the 8 cases with crypttococcosis caused by C. neoformans var. gatti lived in rural areas during their first 10 years. A statistically significant difference existed between the nonimmunosuppressed group (group 1) and the immunosuppressed patients (groups 2 and 3) in the comparison of the distribution of the gattii and neoformans varieties (p.01). The omnipresence of C. neoformans var. neoformans, the urban population's regular exposure to C. neoformans var. neoformans, and predisposing conditions (i.e., immunosuppression) to crypttococcosis likely accounted for the neoformans variety mainly being the cause of crypttococcosis in areas in Brazil where C. neoformans var. gattii is indigenous.