Chaetomium perlucidum
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| Chaetomium perlucidum | |
|---|---|
Scientific classification  | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Sordariomycetes |
| Order: | Sordariales |
| Family: | Chaetomiaceae |
| Genus: | Chaetomium |
| Species: | C. perlucidum |
| Binomial name | |
| Chaetomium perlucidum Sergeeva (1956) | |
| Synonyms | |
Chaetomium perlucidum is a neurotropic[3] dematiaceous (melanated cell wall)[4] fungus that is naturally found in the soil,[5] including in agricultural soil,[6] and in the stems of dead plants.[7] The fungus can also be found on the feathers of birds, manure, seeds, and even paper.[3] It is able to thrive at temperatures of 35 and 42 °C (95 and 108 °F).[3]
The fungus is an invasive opportunist[3][4] to humans that can cause diseases such as onychomycosis (fungus on nails), otolaryngologic (head and neck) or respiratory inflammations (like sinusitis, pneumonia, and empyema), and brain necrosis.[3]
Morphology
Chaetomium perlucidum is pigmented and dark in colour, appearing hairy and wooly, with a growth rate of 4-5 mm/day.[3]
Perithecia (fruiting body)
Chaetomium perlucidum's fruiting bodies become fully mature in 13-16 days.[3] The fruiting body's structural width is 90-200 μm, with an ostiolar pore (open pore) width of 30-50 μm.[3]
Setae (bristle / "hair" structures)
Setae width is 2-3 μm and can have lengths of up to 700 μm.[3] The setae are unbranched and appear to undulate.[3]
Mature ascospores
Fully mature ascospores are 12.5-14 μm x 6-7.5 μm in size.[3] They are smooth, oval-shaped, and brown in colour.[3]
Lipid / fatty acid composition
Chaetomium perlucidum is composed of saturated, monounsaturated, and polyunsaturated fatty acids.
| Fatty acid | Amount (%) |
|---|---|
| Pentadecylic acid / pentadecanoic acid (15:0, CH3(CH2)13COOH) | 0.42 ± 0.33 |
| Palmitic acid / hexadecanoic acid (16:0, C16H32O2) | 18.95 ± 0.92 |
| Palmitoleic acid (16:1, C16H30O2) | trace amounts |
| Stearic acid / octadecanoic acid (18:0, C18H36O2) | 6.76 ± 0.45 |
| Oleic acid (18:1, CH3(CH2)7CH=CH(CH2)7COOH) | 7.38 ± 5.79 |
| Linoleic acid (18:2, C18H32O2) | 63.48 ± 3.71 |
Pathogenicity
The fungus can cause chronic fungal infections in humans.[3][10] An infection can spread throughout the body from a single point of infection into various other systems, e.g., the central nervous, cardiovascular, respiratory, and immune systems, with especially a low prognosis for cerebral infections.[3]
Mode of transmission and infection
Infections take hold in the brain and progress to spread throughout the body.[3] Pathways of entry into the host's body include via cutaneous lesions, oral intake, or intravenously.[3]
Susceptibility
There have been at least two reported cases of cerebral phaeohyphomycosis in humans with one case resulting in death, reported in 2003.[3] Both cases occurred in immunosuppressed individuals already suffering from complications of other unrelated diseases.[3] Recreational drug users, or patients who have undergone intravenous or transplant procedures at even hospitals are also susceptible to being infected by C. perlucidum.[3]
Treatment and prognosis
Most Chaetomium fungal diseases are without known cure[3] and in one case of death from 1996, antifungal therapy through administering Amphotericin B (AMB) proved ineffective.[11] AMB is a common and leading antibiotic treatment prescribed for fungal infections.[12] In one case, C. perlucidum infection in the brain caused death from hemorrhaging throughout the body (especially in the brain) and complications that arose from acute inflammation.[3] However, the physical removal of a C. perlucidum growth through a lobectomy (surgically removing the fungal growth from an area of affected organ/s) was successful in curing another patient from infection.[3]