Colonies are slow growing, forming a waxy, glabrous, convoluted thallus with a cream to buff coloured surface and no reverse pigment. Note surface pigmentation may vary from cream to yellow to deep red and a flatter white form sometimes occurs. Cultures rapidly become downy and pleomorphic. Microscopic morphology is negative, no microconidia or macroconidia are produced. However, irregular branching hyphae with prominent cross walls ("bamboo hyphae") and chlamydoconidia are seen. The so-called "bamboo hyphae" is a characteristic of this species. RG-2 organism.
Culture of Microsporum ferrugineum.
"Bamboo hyphae" of M. ferrugineum.
Microsporum ferrugineum is an anthropophilic fungus causing epidemic juvenile tinea capitis in humans. The clinical features are similar to those of infections caused by M. audouinii. Invaded hairs show an ectothrix infection and fluoresce a greenish-yellow under Wood's ultra-violet light. Reported from Asia (including China and Japan), USSR, Eastern Europe and Africa.
Rippon, J.W. 1988. Medical Mycology. 3rd Edition. W.B. Saunders Co., Philadelphia, USA