212 INFECTIONS CAUSED BY MOLDS 



capable of causing mycetoma ^' '' the diagnosis is not complete until 

 the fungus is isolated in culture and identified. 



Pus should be collected and examined for granules. The shape, 

 size, consistency, and color of these should be noted. A drop of pus 

 containing granules should be placed on a slide under a cover slip. 

 If the pus is thick it can be mixed with a drop of 10 per cent sodium 

 hydroxide. Most of the fungi causing mycetoma grow on Sabouraud 

 agar, although some of them grow very slowly at first. The optimum 

 temperature for most species is near 30° C. 



Treatment and Diagnosis. Although mycetoma usually remains 

 localized and does not endanger life, a few cases have been observed 

 in which systemic infection has been caused by fungi similar to those 

 found in some rare types of mycetoma. (Actinomycosis caused by 

 Actinomyces bovis is excluded from this discussion.) In the great 

 majority of cases the infection does not extend above the foot even 

 in cases of many years' duration. The prognosis from the view- 

 point of life is therefore good, but no treatment of the infection, 

 except radical surgery, is effective. 



Appearance of the Fungi in Tissues. In all cases of mycetoma 

 the fungus forms granules or microcolonies in the tissues, but these 

 differ, as noted above. AVhen Nocardia madurae and A^". mexicana 

 are involved the granules are composed of densely packed, radiating, 

 delicate hyphae 0.5/u, to Ijx in diameter. The color is white or yellow. 

 N. somaliensis and A^. Pelletieri also form granules with small hyphae 

 but the color is reddish yellow or red. 



The granules as well as the hyphae formed by Hyphomycetes and 

 Ascomycetes are somewhat larger than those formed by Nocardia. 

 In some cases chlamydospores are conspicuous elements of the 

 granule. Phialophora Jeanselmei^ and species of Madurella form 

 black granules. The granules formed by Allescheria Boydii [Mono- 

 sporium apiospermum) , Indiella spp., and Aspergillus spp. are white 

 to yellowish. The granule may be composed largely of chlamydo- 

 spores, but usually there is some degree of radial orientation of 

 hyphae. There is sometimes an acidiphilic zone at the periphery of 

 sectioned granules and this staining reaction and the enlarged hyphal 

 tips at the periphery bear a superficial resemblance to the "clubs" 

 which surround the granule of Actinomyces bovis. See Chapter XIII, 



Appearance in Culture. The large number of species of fungi as- 

 sociated with mycetoma make it impossible to generalize about their 

 characteristics in culture. A few representative fungi will be de- 

 scribed briefly. 



