Phaeohyphomycosis caused by a novel species, Pseudochaetosphaeronema martinelli

Abstract

Among the opportunistic mycoses that are emerging in patients with immunosuppression or severe underlying illness, many isolates lack of characteristic sporulation and until recently could not be identified. Clinical signs are mostly nonspecific and therefore such infections have often been disregarded. In the present paper we describe a novel, nonsporulating fungal species causing subcutaneous phaeohyphomycosis in two patients of different origin. One is a 73-year-old female from Martinique who suffered from rheumatoid arthritis, while the other case concerns a 72-year-old male from Mexico who had a history of type 2 diabetes mellitus. Sequencing of the partial ribosomal operon revealed that in both cases a member of the order Pleosporales was concerned which could not be affiliated to any family within this order. Multilocus analysis revealed that the fungus was related to another, unaffiliated agent of human mycetoma, Pseudochaetosphaeronema larense, and therefore the name Pseudochaetosphaeronema martinelli was introduced.