Abstract
Cycloheximide (up to 0.4 g/liter) was significantly more inhibitory to the growth of three isolates of Aspergillus fumigatus at 23 C than at 37 or 45 C. Preincubation of the media for 7 days at 45 C did not alter the inhibitory effect of the cycloheximide at 23 C. Neither mutation nor adaptation in the fungus seems to be the reason for its growth on the antibiotic at the higher temperature. The mechanism for the differences in sensitivity as related to temperature of incubation cannot be explained at this time.