Cladosporium

Number of species: Approximately 40 species.
Toxins: Some Species; Cladosporin, Emodin, Epiclosporic acid.

Cladosporium is the most frequently found genus of fungi in outdoor air in temperate climates. The conidia, borne in very fragile chains, easily become airborne and are transported over long distances. The natural high season for outdoor air concentrations is typically late summer and autumn and low season is typically winter and early spring. It has been isolated from many different types of soil and is a major colonizer of plant liter. The enzymes of Cladosporium are especially suited for breaking down cellulose, pectin and lignin, which are the major components of plant litter. Due to its ability to rapidly invade many different ecological niches, Cladosporium is considered ubiquitous and therefore sometimes problematic. The ability to sporulate heavily, ease of dispersal, and buoyant spores makes this fungus an important fungal airway allergen, and together with Alternaria, commonly causes asthma and hay fever in the Western Hemisphere. It is found indoors as well, but usually in less numbers, unless there is an indoor source of contamination. Indoors this fungus may be encountered in dirty refrigerators, especially in reservoirs where condensation is collected, and on moist window frames as a result of condensation. Cladosporium often discolors interior paint, paper, and textiles stored under humid conditions. Houses with poor ventilation and houses located in damp environments may have heavy concentrations of Cladosporium.