Apophysomyces
Encyclopedia
Apophysomyces is a filamentous fungus that is commonly found in soil and decaying vegetation. It normally grows in tropical to subtropical regions.
The genus Apophysomyces historically was monospecific, with the only species Apophysomyces elegans. However, recently were described three new species; Apophysomyces variabilis, Apophysomyces trapeziformis, and Apophysomyces ossiformis.
. However, its bell-shaped (although not conical) apophyses (outgrowth), the existence of its foot-cell like hypha
l segment, rhizoid
s produced opposite to the sporangiophores upon cultivation on plain agar
, the darker and thicker subapical
segment, and inability to sporulate on routine culture media help in distinguishing Apophysomyces elegans.
Apophysomyces elegans is a thermotolerant fungus: it has been found to grow favourably at temperatures of 26°C and 37°C, and it grows rapidly at 42°C. Its colonies are fluffy and cottony in appearance. The surface of the colony is white initially and turns to a brownish-grey or yellowish-cream as the culture ages, while the underside is white to pale yellow in colour.
However, Apophysomyces elegans is the cause of the rare infection, known as zygomycosis, in humans, which is often fatal.
Infection is usually acquired via traumatic implantations associated with soil or decaying vegetable matter (such as from accidental injuries or insect bites). Invasive soft tissue infections can develop on burns or wounds which are contaminated by soil. Unlike other zygomycosis, the affected host is usually otherwise immunocompetent. Apophysomyces elegans infections present most commonly as necrotizing fasciitis
, osteomyelitis
, and angioinvasion. Systemic and secondary renal and bladder infections have also been reported.
The genus Apophysomyces historically was monospecific, with the only species Apophysomyces elegans. However, recently were described three new species; Apophysomyces variabilis, Apophysomyces trapeziformis, and Apophysomyces ossiformis.
Characteristics
Among the other members of zygomycetes, Apophysomyces elegans mostly resembles those from genus AbsidiaAbsidia
Absidia is a genus of fungi in the family Mucoraceae. The best known species is the pathogenic Absidia corymbifera, which causes zygomycosis, especially in the form of mycotic spontaneous abortion in cows. It can also cause mucormycosis in humans. It is an allergenic that could cause mucorosis in...
. However, its bell-shaped (although not conical) apophyses (outgrowth), the existence of its foot-cell like hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...
l segment, rhizoid
Rhizoid
Rhizoids are thread-like growths from the base or bottom of a plant, found mainly in lower groups such as algae, fungi, bryophytes and pteridophytes, that function like roots of higher plants ....
s produced opposite to the sporangiophores upon cultivation on plain agar
Agar
Agar or agar-agar is a gelatinous substance derived from a polysaccharide that accumulates in the cell walls of agarophyte red algae. Throughout history into modern times, agar has been chiefly used as an ingredient in desserts throughout Asia and also as a solid substrate to contain culture medium...
, the darker and thicker subapical
Apical
Apical, from the Latin apex meaning to be at the apex or tip, may refer to:*Apical , an anatomical term of location for features associated with the base of an organism or structure...
segment, and inability to sporulate on routine culture media help in distinguishing Apophysomyces elegans.
Apophysomyces elegans is a thermotolerant fungus: it has been found to grow favourably at temperatures of 26°C and 37°C, and it grows rapidly at 42°C. Its colonies are fluffy and cottony in appearance. The surface of the colony is white initially and turns to a brownish-grey or yellowish-cream as the culture ages, while the underside is white to pale yellow in colour.
Pathogenicity
Normally, no special precautions are needed with regard to this fungus.However, Apophysomyces elegans is the cause of the rare infection, known as zygomycosis, in humans, which is often fatal.
Infection is usually acquired via traumatic implantations associated with soil or decaying vegetable matter (such as from accidental injuries or insect bites). Invasive soft tissue infections can develop on burns or wounds which are contaminated by soil. Unlike other zygomycosis, the affected host is usually otherwise immunocompetent. Apophysomyces elegans infections present most commonly as necrotizing fasciitis
Necrotizing fasciitis
Necrotizing fasciitis , commonly known as flesh-eating disease or Flesh-eating bacteria syndrome, is a rare infection of the deeper layers of skin and subcutaneous tissues, easily spreading across the fascial plane within the subcutaneous tissue.Necrotizing fasciitis is a quickly progressing and...
, osteomyelitis
Osteomyelitis
Osteomyelitis simply means an infection of the bone or bone marrow...
, and angioinvasion. Systemic and secondary renal and bladder infections have also been reported.
See also
- MucormycosisMucormycosisZygomycosis is the broadest term to refer to infections caused by bread mold fungi of the zygomycota phylum. However, because zygomycota has been identified as polyphyletic, and is not included in modern fungal classification systems, the diseases that Zygomycosis can refer to are better called by...
(specific term for infection caused by Mucoraceae family moulds) - Zygomycosis (a more generic term for infection caused by Mucoraceae and various other mould varieties; the term PhycomycosisMucormycosisZygomycosis is the broadest term to refer to infections caused by bread mold fungi of the zygomycota phylum. However, because zygomycota has been identified as polyphyletic, and is not included in modern fungal classification systems, the diseases that Zygomycosis can refer to are better called by...
is also used).
External links
- Image of Apophysomyces sp.
- doctorfungus.org entry on Apophysomyces sp.
- Apophysomyces species from Index Fungorum
- PubMed search page (using search term "apophysomyces")
