Wikipedia
Chaetomium is a genus of fungi in the Chaetomiaceae family. It is a dematiaceous (dark-walled) mold normally found in soil, air, cellulose and plant debris. According to the Dictionary of the Fungi (10th edition, 2008), there are about 95 species in the widespread genus.
Members of this genus typically have superficial, ostiolar perithecia, covered in hairs. Asci are often clavate and evanescent, bearing eight spores. Ascospores are usually lemon-shaped, commonly colored olive-brown. Mycelia often grows in conglomerate masses that resemble rope.
As well as being a contaminant, Chaetomium spp. are also encountered as causative agents of infections in humans. Many cases cause type 1 allergic reactions and infections. A few cases of fatal deep infections due to Chaetomium atrobrunneum have been reported in the immunocompromised host. Other clinical syndromes include brain abscess, peritonitis, and onychomycosis.
Some Chaetomium infections in humans can be avoided with proper hygiene habits. For instance, the Sohnian Kittah strain's presence can often be eliminated entirely with household products.