Susceptibility to heat and antifungal agents of Cryptococcus neoformans var. neoformans (Serotype D) isolated from Eucalyptus spp in Rio Grande do Sul, Brazil

Abstract

Este estudo foi realizado com os primeiros isolados ambientais de C. neoformans sorotipo D, obtidos no Rio Grande Susceptibility of C. neoformans to heat and antifungal agents 5 do Sul. Objetivando-se avaliar a susceptibilidade a agentes antifúngicos de forma mais rigorosa, utilizou-se a técnica de referência proposta pelo NCCLS, Caldo Yeast Nitrogen Base (YNB) proposto por Ghannoum et al., Antibiotic medium 3, caldo YNB adequado à metodologia do NCCLS e o E-test. Os resultados indicaram que todos os isolados foram sensíveis à anfotericina B (0,0625 -0,5 μg/mL), fluconazol (0,125 – 4,0 μg/ mL), itraconazol (0,031 – 0,25 μg/ml) e fluorocitosina (0,125-4,0 μg/mL) através das técnicas empregadas. Nos testes de termotolerância (47ºC/30 min), observou-se que as culturas de C. neoformans sorotipo D são mais sensíveis do que as de C. neoformans sorotipo A.

In this work we studied the susceptibility to heat and antifungal agents of the first strains of environmental Cryptococcus neoformans var neoformans (serotype D) isolated in the state of Rio Grande do Sul, Brazil. In order to achieve a rigorous analysis, we employed the methodology recommended by NCCLS, Yeast Nitrogen Base (YNB) proposed by Ghannoum et al (YNB-1), Antibiotic medium 3 (AM3) indicated by others, YNB adjusted to the NCCLS methodology (YNB-2) and Etest. Our results indicate that all strains were susceptible to amphotericin B (0.0625 – 0.5 μg/mL), fluconazole (0.125 – 8.0 μg/mL), itraconazole (0.031 – 0.25 μg/mL) and flucytosine (0.125 – 4.0 μg/mL). The C. neoformans serotype D strains were more susceptible to heat (47ºC / 30 min) than C. neoformans serotype A.