Antibiotic sensitivity of the yeast and mycelial phases ofHistoplasma capsulatum

Abstract

Cycloheximide and chloramphenicol in combination have a greater effect on yeast cells of Histoplasma capsulatum than on the mycelial phase of this fungus. In contrast, clotrimazole was found to be more effective against mycelia. Miconazole produced a pronounced effect against both phases whereas tolnaftate was only slightly active. Sulfadiazine and griseofulvin were completely inactive against both phases. The differential sensitivities of the 2 phases of H. capsulatum to various antibiotics can be useful in studying the transition of this dimorphic fungus from 1 phase to the other. La combinación de cloramfenicol y cicloheximida tiene un efecto más marcado sobre la forma de levadura de Histoplasma capsulatum que sobre la forma micelial. Miconazole tuvo un efecto pronunciado sobre ambas fases mientras que tolnaftato demostró leve actividad. Griseofulvin y sulfadiazina carecen de efecto alguno sobre dichas fases. La sensitividad diferencial a varios antibióticos de las dos formas de H. capsulatum puede ser útil en el estudio de la transición de una forma a otra de este hongo dimórfico.