Chaetomium

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Commonly found on deteriorating wood products, chaetomium frequently emits a musty odor and is frequently found on water-damaged drywall and other lower cost construction products often used in the United Sates. It's health effects have not been well studied, however some rare compounds have on occasion been identified as mutagenic. Currently, more definitive studies are being conducted with some rather distressing results. Chaetomium are a common fungal species with a ubiquitous distribution with over 80 species currently known. Chaetomium colonies are rapidly growing, cottony and white in color initially. Mature colonies become grey to olive in color. From the reverse, the color is tan to red or brown to black. Fruiting structures of this mold look like olive-green cockleburs - 1/16 inch in diameter - that develop on compost. Although its heat tolerant spores survive 140 F for 6 hours, the mold appears only in compost improperly managed during Phase II, especially where Phase II ventilation is inadequate. Lack of oxygen when compost temperatures are greater than 142 F permits formation of compounds produced in anaerobic conditions. These compounds are toxic to spawn growth but are utilized by the olive green mold. It is highly cellulolytic. A vast amount of medical news has been downplayed regarding Chaetomium in past literature. Chaetomiumspp. are among the fungi causing infections wholly referred to as phaeohyphomycosis. Fatal deep mycoses due to Chaetomium atrobrunneum have been documented. Brain abscess, peritonitis, cutaneous lesions, and onychomycosis may also develop due to Chaetomium spp.

Unlike most other mold pathogens, there is medical evidence to suggest that people who are exposed to Chaetomium may have permanent neurological damage of the myelin sheath. Therefore, a noticeably high incidence of autoimmune diseases have been linked to exposure of this mold such as Multiple Sclerosis, Lupus, etc. It has also been linked to certain forms of Cancer. As with other fungal exposure, it also causes permanent DNA damage. This has been documented in several cases being researched during studies. Chaetomium is the only mold that inhibits cell replication.

Chaetomium are found on a variety of substrates containing cellulose including paper and plant compost. Several species have been reported to play a major role in the decomposition of cellulose-made materials. These fungi are able to dissolve the cellulose fibers in cotton and paper and thus cause the materials to disintegrate. The process is especially rapid under moist conditions.

This fungus is reported to be allergenic and a toxin. It is an ascomycete and in most species the spores are lemon-shaped. The spore column results from the breakdown of the asci within the body of the perithecium. The perithecia of Chaetomium are superficial and barrel-shaped, and they are clothed with dark, stiff hairs.

Chaetomium globosum produces the mycotoxin chaetoglobosin, which is reported to block cytoplasmatic division when the route of exposure is intravenous injection. Unfortunately, little data is available regarding inhalation of chaetoglobosin.

On a scale of worst to more mild in effects on human health, contrary to what many believe; chaetomium would be second or possibly third to aspergillus only to stachybotrys. Buildings found to chaetomium are one of the few types of fungi that are actually irremediable by any means. The only means of destroying the building would probably be to bury it, as fire would not be hot enough.

Chaetomium Kunze is a large genus of the Chaetomiaceae Winter (Sordariales Chad. ex D. Hawksw. & O. E. Erikss., Ascomycota) which comprise more than one hundred species (Arx et al 1986, Cannon 1986 , Cano and Guarro 1987, Carris and Glawe 1987 , Moustafa and Ess El-Din 1988 , Abdullah and Al-Bader 1989 , Horie and Udagawa 1990, Pande and Rao 1990 , Udaiyan and Hosagoudar 1991 , Abdullah and Zora 1993 , Udagawa et al 1994 , Gené and Guarro 1996 , Decock and Hennebert 1997 , Udagawa et al 1997 ), and are found in the most diverse substrates and geographic regions. Chaetomium species are characterized by superficial ascomata, usually covered with hairs or setae mainly surrounding a rather broad apical ostiolar pore, and attached to the substrate by rhizoidal hyphae.

Their ascospores are aseptate, brown or gray-olivaceous with one or two germ pores. During the course of a study of soil fungi from different regions of the world we have isolated numerous strains of this genus, some of them belonging to undescribed species. As with many fungi, new strains are constantly being recognized.

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Suggested Reading / Abstract

• Abdullah SK, Zora SB., 1993 Chaetomium mesopotamicum, a new thermophilic species from Iraqi soil Crypt Bot 3:387-389
• Arx JA von, Guarro J, Figueras MJ., 1986 The Ascomycete genus Chaetomium Beih Nova Hedwigia 84:1-162
• Cannon PF., 1986 A revision of Achaetomium, Achaetomiella and Subramaniula, and some similar species of Chaetomium Trans Br Mycol Soc 87:45-76
• Cano J, Guarro J., 1987 Soil ascomycetes from Spain XII Nova Hedwigia 44:543-546
• Carris LM, Glawe DA., 1987 Chaetomium histoplasmoides, a new species isolated from cysts of Heterodera glycines in Illinois Mycotaxon 29:383-391
• Decock C, Hennebert GL., 1997 A new species of Chaetomium from Ecuador Mycol Res 101:309-310
• de Hoog, G. S., J. Guarro, J. Gene, and M. J. Figueras. 2000. Atlas of Clinical Fungi, 2nd ed, vol. 1. Centraalbureau voor Schimmelcultures, Utrecht, The Netherlands.
• Friedman, A. H. 1998. Cerebral fungal infections in the immunocompromised host: A literature review and a new pathogen - Chaetomium atrobrunneum: Case report - Comment. Neurosurgery. 43:1469
• Guarro, J., L. Soler, and M. G. Rinaldi. 1995. Pathogenicity and antifungal susceptibility of Chaetomium species. Eur J Clin Microbiol Infect Dis. 14:613-618
• Guppy, K. H., C. Thomas, K. Thomas, and D. Anderson. 1998. Cerebral fungal infections in the immunocompromised host: A literature review and a new pathogen - Chaetomium atrobrunneum: Case report. Neurosurgery. 43:1463-1469
• Gray, Michael, 2001. Mold, Mycotoxins and Human Health
• Hawksworth DL., 1975 Farrowia, a new genus in the Chaetomiaceae Persoonia 8:167-185
• Horie Y, Udagawa S., 1990 New or interesting Chaetomium species from herbal drugs Trans Mycol Soc Japan 31:249-258
• Kornerup A, Wanscher JH., 1984 Methuen Handbook of Color. 3rd ed London: Erye Methuen. 252 p
• Larone, D. H. 1995. Medically Important Fungi - A Guide to Identification, 3rd ed. ASM Press, Washington, D. C.
• Mouchacca J., 1997 Thermophilic fungi: Biodiversity and taxonomic status Cryptog Mycol 18:19-69
• Moustafa AF, Ess El-Din., 1988 Chaetomium sinaiense sp. nov., a new soil ascomycete from Egypt Can J Bot 67:3417-3419
• Pande A, Rao VG., 1990 Ascomycetes of western India-XIV J Econ Tax Bot 14:157-161
• Pujol, I., J. Guarro, C. Llop, L. Soler, and J. Fernandez-Ballart. 1996.comparison study of broth macrodilution and microdilution antifungal susceptibility tests for the filamentous fungi. Antimicrob. Agents Chemother 40:2106-2110
• Rock, J. P. 1998. Cerebral fungal infections in the immunocompromised host: A literature review and a new pathogen- Chaetomium atrobrunneum: Case report - Comment. Neurosurgery. 43:1469
• Seth HK., 1970 A monograph of the genus Chaetomium Beih Nova Hedwigia 37:1-133
• Stchigel AM, Cano J, Mac Cormack W, Guarro J., 2001 Antarctomyces psychrotrophicus gen. et sp. nov., a new ascomycete from Antarctica Mycol Res 105:377-382
• Sutton, D. A., A. W. Fothergill, and M. G. Rinaldi (ed. ) 1998. Guide to Clinically Significant Fungi, 1st ed. Williams & Wilkins, Baltimore
• Udagawa S, Uchiyama S, Kamiya S., 1994 Two new species of pyrenomycetous Ascomycetes from New Caledonia Mycoscience 35:319-325
• Udagawa S, Toyazaki N, Yaguchi T., 1997 A new species of Chaetomium from house dust Mycoscience 38:399-402