Pleural fluid as nutrient substratum for Aspergillus fumigatus and A. flavus. Submerged growth in pleural fluid and extracellular proteolysis in pleural fluid agar. A preliminary report.

Pleural fluid in liquid and agar form from a patient with adenocarcinoma of the lung was used as a nutrient medium for culturing Aspergillus fumigatus and A, flavus. The extracellular proteolytic activity of both strains could be demonstrated after an incubation period of 5 d at 37 degrees C by the agar block method using pleural fluid agar (protein content ca. 0.1-0.5% and initial pH values of 7.0 and 5.0) and protein staining with naphthalene black. In the undiluted pleural fluid, after stationary culture at 37 degrees C for 8 days, compact white granule-like colonies of a size of ca. 0.5-1.0 mm were found near the surface of the liquid and as sediment. Microscopically, these colonies consisted of radially arranged septate hyphae, similar in size and form to those seen in invasive aspergillosis.