Scopulariopsis Mold Species
The
U.S. Government's Occupational Safety and Health Administration [OSHA]
Scopulariopsis
species are causative agents of
Dermatophytosis, (Information from www.doctorfungus.org @ 2005)
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Taxonomic Classifications
Kingdom:
Fungi
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Ecology
Scopulariopsis is a cosmopolitan filamentous fungus that thrives in soil, plant material, feathers, and insects. Scopulariopsis species, aside from being considered as contaminants, are agents of infections in humans, particularly in immunocompromised patients. Certain Scopulariopsis species attack bee larvae and silkworms as well. Additionally, Scopulariopsis is a weakly keratinolytic fungus which is highly resistant to benomyl. Several species of Scopulariopsis have teleomorphs which are placed under the genus Microascus.
Species
The genus Scopulariopsis is distinctive as it contains both moniliaceous (hyaline) and dematiaceous species, wherein some are considered as clinically important. The most common is Scopulariopsis brevicaulis which is a hyaline fungus. Other hyaline species include Scopulariopsis candida, which maintains its white color at maturity rather than becoming buff - colored, Scopulariopsis koningii, Scopulariopsis acremonium, and Scopulariopsis flava. Dematiaceous species include Scopulariopsis cinerea which is the anamorph of Microascus cirrosus, Scopulariopsis brumptii, Scopulariopsis chartarum, Scopulariopsis fusca, and Scopulariopsis asperula.
Pathogenicity and Health Effects
Scopulariopsis species is rarely a cause of human infection. Onychomycosis especially of the toe nails by Scopulariopsis is occasionally reported. Skin lesions, brain abscess, mycetoma, keratitis, endocarditis, endophthalmitis, invasive sinusitis, and disseminated infections due to Scopulariopsis species have been rarely reported. Infections caused by Scopulariopsis are observed mainly in immunocompromised patients such as bone marrow transplant recipients.
The association with human deaths by producing arsine gas from arsenate dyes found in wall paper is considered as one of the striking features of Scopulariopsis brevicaulis. Volatilization and methylation of dimethylarsinic acid and methylation of arsenate and arsenite naturally occur in soil. These biochemical reactions have production of trimethylarsine and dimethylarsine as the end - products. Arsenic is found in pesticides as well. Arsine is the most toxic form of arsenic. It gives off garlic – like odor at concentrations above 0.5 ppm and it is still toxic at concentrations even lower than 0.5 ppm.
In the 1810s, arsenate dyes were manufactured and incorporated into wallpapers and the most famous was Schweinfurter green. The widespread use of these green – colored wallpapers has led to the illnesses, such as tubular necrosis and renal failure, and death of people who slept in green wall – papered rooms. Emission of garlic – like odor in some rooms was noted as well. In 1897, B. Gosio, an Italian chemist, showed that the cause of the deaths was due to the production of a gas which could not be identified at that time thus, led to the so – called Gosio gas. Then in 1945, Frederick Challenger was able to identify the gas as trimethylarsine which was produced by the mold fungus Penicillium brevicaulum which is known today as Scopulariopsis brevicaulis. Scopulariopsis brevicaulis consumes the starch found in the wallpaper paste while it converts the arsenate found in the paper to trimethylarsine oxide. Lastly, this oxide is further reduced into the fatal and death – causing trimethylarsine gas which is then released. Though this phenomenon was primarily linked only to Scopulariopsis brevicaulis, other molds present in the environment may also be able to discharge volatile arsenic compounds theoretically by using the same mechanism.
Macroscopic Appearance
Ø Growth rate is moderately rapid and mature within five days and colonies are velvety to powdery in texture; Ø The surface colony color is white initially becoming light brown or buff tan in maturation while reverse is tan with brownish center; and Ø Some species may even form dark – colored colonies.
Microscopic Appearance
Ø Septate hyaline hyphae, conidiophores, annellides, conidia, and chlamydospores (occasionally), are present; Ø Conidiophores are dark, may be simple or branched, hyphae – like, and with annellides; Ø Annellides may be solitary, appear in clusters, or may form a penicillus which are cylindrical and slightly swollen; and Ø Conidia are hyaline or dark gray in color, unicellular, globose to pyriform with truncate bases, smooth or rough – walled, and appear in basipetal chains.
Laboratory Precautions
General laboratory precautions are required, no special safety measures needed.
Susceptibility Limited data are available on the susceptibility activity of Scopulariopsis species. MICs of fluconazole, itraconazole, and the novel azole Syn - 2869 are high, showing that some azoles have no or very limited in vitro activity against isolated of Scopulariopsis. Flucytosine MICs are also high, while amphotericin B, ketoconazole and voriconazole MICs are variable. Terbinafine with azoles appears synergistic against Scopulariopsis brevicaulis isolates. For the determination of the entire extent of in vitro activity of various antifungal compounds against isolates of Scopulariopsis of various species large – scale studies are required.
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The mycological information gathered and
A
Clinical Laboratory Handbook:
Entire Home Mold Testing
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