Variation in Vivo and Isolation of Aspergillus fumigatus from a Case of Human Aspergillosis

SUMMARYFrom a case of human pulmonary aspergillosis two morphologically different strains of Aspergillus were isolated. Both strains produced gray-green colonies with abundant conidiophores and conidia characteristic of Aspergillus fumigatus when grown on Sabouraud's dextrose agar at 37 C. However, on cycloheximide-containing media, one strain, apparently a variant that arose in vivo, produced a white colony which sporulated sparsely. On all media used, the variant strain had a slower growth rate than the wild-type strain. The bearing of the results on therapeutic treatment of mycoses is briefly discussed.