Interaction between aspergilli and streptomycetes in the soil of potted indoor plants: a preliminary report (contribution to the epidemiology of human aspergillosis).

The soil of potted ornamental plants as a reservoir for Aspergillus species pathogenic for man is of epidemiological and ecological interest. Isolation of A. niger as the sole hyphomycete from the soil of potted African violets (Saintpaulia ionantha, Gesneriaceae), prompted us to look for A. inger on the surface of the roots of this plant. Small pieces of the roots were inoculated in the nutrient-free agar-gel with and without antibiotics. On the antibiotic-free gel, a dense growth of Streptomyces griseus was consistently observed around the root pieces. But the gel fortified with antibiotics showed pure growth of only A. niger. One of the two strains of S. ariseus isolated from the African violet, showed inhibitory effect against a number of fungi including A. niger but the other strain had no effect on this fungus. The possible influence of streptomycetes on the occurrence of aspergilli in the soil of potted ornamental plants is discussed.