GEOGRAPHICAL DISTRIBUTION 



213 



Species of Nocardia retain in culture the small size which char- 

 acterizes their hyphae in granules in pus. Nocardin madurae grows 

 on agar as a glabrous, wrinkled, grey colony which is in some in- 

 stances covered with short, white, aerial hyphae. No conidia are 

 formed but in old cultures the cells formed by fragmentation of the 

 hyphae serve as reproductive structures. N. mexicana grows slowly 

 and forms heaped, folded colonies rather than spreading widely over 

 the agar surface. The color varies from white (in strains or cultures 

 with aerial hyphae) to yellow or 

 orange. Most strains have a 

 strong musty odor. See page 379 

 for further discussion of myce- 

 tomas caused by Nocardia spp. 



Phialophora Jeansehnei grows 

 on Sabouraud agar as a mouse- 

 grey to olive-colored colony closely 

 resembling that of P. verrucosa 

 which causes chromoblastomyco- 

 sis." There is also a close micro- 

 scopical resemblance between the 

 two fungi. Species of IMadurella 

 are grey to black and most of 

 them grow slowly, forming dome- 

 shaped colonies in which conidia 

 are very few or entirely lacking. 



Perhaps the most frequent cause 

 of mycetoma in the United States 



Fig. 107. Allescheria Boydii. Co- 

 nidial stage {Monosporium apiosper- 

 viuvi) on Sabouraud agar. From 

 Conant et al., Manual of Clinical 

 Mycology, Saunders, 1944. 



is Monosporium apiospermum. It has been shown recently that this 

 fungus is the imperfect form of Allescheria Boydii.^ The fungus 

 produces on Sabouraud agar a rapidly spreading, floccose, mouse- 

 grey colony. The conidia are borne singly or in small groups at the 

 tips and sides of simple or branched conidiophores. They are el- 

 liptical, egg-shaped, or clavate, with a truncate base, and, under the 

 microscope, they are brown. They are 3.5 to 7.5 by 5 to 15/x. 



The ascocarp of A. Boydii is globose, 50 to 200/a in diameter, with- 

 out ostiole (cleistocarpous) and the wall is thin and dark brown. 

 The asci are subglobose, 8 to 20;a in diameter, evanescent, and each 

 contains eight ovoid ascospores 4 to 4.5 by 6 to 7.5/1, in size with 

 slightly thickened brown walls. 



Geographical Distribution. Mycetoma occurs throughout the 

 world but is more common in tropical and subtropical countries in 

 persons who do not wear shoes and so are more often exposed to 



