Laboratory isolation techniques in human and experimental fungal infections.

In laboratory experience with a heterogenous group of 26 human ocular fungal isolates, brain-heart infusion broth proved to be the most useful medium for isolation. Although Candida and Fusarium species grew out within four days of inoculation, one fourth of the cultures did not become positive until 14 to 19 days had elapsed. In an animal model of endophthalmitis due to F. solani infection, brain-heart infusion broth again was the most useful. The highly nutritious media used for fungal isolation are prone to contamination by organisms that are difficult to distinguish from true pathogens. Sham culture studies demonstrated that this contamination can easily occur during the process of sampling the lesion and inoculating the media.