Morphological and physiological studies of isolates of Hendersonula toruloidea Nattrass cultured from human skin and nail samples.

Primary isolates from 128 cases of superficial Hendersonula toruloidea infection were invariably of the hyphomycete Scytalidium synanamorph of the fungus, characterized by the formation of dematiaceous fission arthroconidia. Three distinct colonial forms were recognized which were stable on repeated sub-culture. The growth rates of four isolates of each colonial form were determined at 25 degrees C, 30 degrees C, 37 degrees C and 40 degrees C. The production of the coelomycete synanamorph was investigated on a range of agar and natural media. Pycnidial or stromatal conidiomata were observed in representatives of two of the three colonial forms. All the infections were diagnosed in patients who had originated from, or resided in tropical, subtropical or warm temperate areas and the distribution of the different colonial forms was significantly related to the geographical/racial origins of the patients.