[Isolation and characterization of Cryptococcus neoformans var. gattii from samples of Eucalyptus camaldulensis in Mexico city.]. / Aislamiento y caracterización de Cryptococcus neoformans var. gattii a partir de muestras de Eucalyptus camaldulensis en la ciudad de México.

The habitat of Cryptococcus neoformans var. gattii is not fully known in Mexico. We investigated the relationship of the yeast with Eucalyptus camaldulensis soil in three main Avenues of the city. A total of 135 trees of the species E. camaldulensis, were selected. Samples were taken in duplicate from the ground containing vegetable debris, tree cortex, leaves and flowers. Isolation of the yeast was made on Guizotia abyssinica media, using Staib technique. The identification was accomplished by biochemical and morphologic tests, and caraterization of the variety was made by bromotimol canavanine-glycine-blue (CGB) and D-proline tests. Isolation of 87 strains of Cryptococcus spp. was acomplished and eight of them were identified as C. neoformans var. gattii. These findings confirmed the close relationship of C. neoformans var. gattii and E. camaldulensis. To our knowledge this is the first report concerning the isolation of this variety from E. camaldulensis trees in Mexico.

Fungal agents isolated from cancer patients.

With the aim to know the frequency of mycotic agents in patients with different types of cancer, samples were obtained from 81 patients from the Hospital de Oncología, Centro Médico Nacional Siglo XXI, IMSS from May 1995 through May 1996. In a conventional grouping seven (7) ambulatory patients were found in early stages, twenty seven (27) occasionally hospitalized patients were found in intermediate stage and forty seven (47) hospitalized patients in terminal stage of cancer. The different samples were processed through routine mycologycal methods and the following fungi species were isolated and identified: fifty four strains (58%) of Candida albicans followed by eleven strains (11.8%) of Candida tropicalis, six strains (6.45%) of Candida parapsilosis, five strains (5.37%) of Candida krusei, four strains (4.3%) of Candida humicola and five strains (5.37%) of Rodothorula rubra. From medical devices like catheter tips, drainage catheters (Pen rouse, Foley) and gallbladder catheters; four (4) strains of C. albicans, three (3) strains of Rodothorula rubra and two (2) strains of Aspergillus sp were isolated. Of the Candida non albicans it was relevant to find C. krusei more frequently than Rodothorula rubra, Aspergillus sp and Penicillum sp. The frequency of the presence of fungi increases commensurately to the advancement of the clincal stage of the cancer.

[Characterization of Cryptococcus neoformans strains isolated from patients with acquired immunodeficiency syndrome (AIDS)]. / Caracterización de cepas de Cryptococcus neoformans aisladas de pacientes con síndrome de inmunodeficiencia adquirida (SIDA).

In Mexico cryptococosis ranks third in frequency among the mycoses ocurring as complications in AIDS patients. Neither the prevalence of the two varieties of C. neoformans in these patients nor the morphological and physiological changes suffered by these strains in AIDS patients are known. A total of 60 isolates were obtained from patients with AIDS from the Hospital de Infectología, Centro Médico "La Raza" IMSS. The identity of each isolate was established by: growth at 37 degrees C, colony and microscopic characteristics, urease and phenoloxidase activity, carbon sources assimilation. The canavanine glycine-bromothymol blue agar was used to distinguish C. neoformans var. neoformans and C. neoformans var. gattii. Pathogenicity in mice was also tested. Fifty one isolates of C. neoformans var. neoformans and nine of C. neoformans var. gattii were identified. All strains grew well at 37 degrees C, urease and phenoloxidase were positive, the morphology and the auxanographic profile were variable. C. neoformans var. neoformans was more virulent in mouse than C. neoformans var. gattii. This study has confirmed the presence of the two varieties of C. neoformans in Mexico with 85% prevalence of var. neoformans and 15% of var. gattii in AIDS patients. This frequency was higher than in reports from other countries.