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Syncephalastrum

Syncephalastrum racemosum colony characteristics in SDA are as shown above image.

Habitats

The fungus Syncephalastrum racemosum is available mainly from soil and dung in tropical and subtropical regions. It can also be a difficult laboratory contaminant.

Macroscopic features of Syncephalastrum

Colonies are very fast-growing, cottony to fluffy, white to light grey, becoming dark grey with the development of sporangia.

Microscopic Features of Syncephalastrum

Broad (4-8 µm in diameter), non-septate or sparsely septate hyphae, sporangiophores, merosporangia , sporangiospores (merospores), and rhizoids are visualized. Septation of the hyphae is mostly observed as the culture gets old. Sporangiophores are frequently branched and rather short. They end up in a vesicle (80 µm in diameter). Around this vesicle are the merosporangia (4-6 x 9-60 µm), which are filled with linear chains of sporangiospores. Each merosporangium contains a single row of 3-18 merospores. Merospores (3-7 µm, may rarely reach 10 µm in diameter) are one-celled and spherical to cylindrical in shape.  Zygospores, when produced, are black, spherical, and 50-90 µm in diameter. They have conical projections. In brief, zygomycete producing sympodially branching sporangiosphores with terminal vesicles bearing merosporangia.

Note: The sporangiophore and merosporangia of Syncephalastrum species may confuse for an Aspergillus species when the isolate is not looking at carefully.

Pathogenicity and Clinical Significance

Syncephalastrum is a very rare causative agent of human zygomycosis. It has so far been isolated in cases of cutaneous infection and otomycosis. It comes under risk group-2 organism.

Laboratory Diagnosis of  Syncephalastrum

Specimen

Skin scrapping

Ear discharge

Direct microscopy

KOH preparation

Culture

Growth on SDA is very fast-growing, cottony to fluffy, white to light grey, becoming dark grey with the development of sporangia.

Treatment

Very limited data are available for treatment. Following antifungal drugs are useful and they are- Amphotericin B, ketoconazole, itraconazole, and voriconazole.

Bibliography

1. A Textbook of Medical Mycology. Editor: Jagdish Chander  Publication Mehata, India.
2. Medical Mycology. Editors: Emmons and Binford, 2^nd ed 1970, Publisher Lea and Febiger, Philadelphia.
3. Practical Laboratory Mycology. Editors: Koneman E.W. and G.D. Roberts, 3^rd ed 1985, Publisher Williams and Wilkins, Baltimore.
4. Description of Medical fungi,  David Ellis, Stephen Davis, Helen Alexiou, Rosemary Handke, Robyn Bartley, Second edition