In Vitro Antifungal Susceptibility of Yeast and Mold Phases of Isolates of Dimorphic Fungal Pathogen Emergomyces africanus (Formerly Emmonsia sp.) from HIV-Infected South African Patients

摘要

The family Ajellomycetaceae (within the order Onygenales) includes phylogenetically related dimorphic fungal genera such as Emmonsia, Histoplasma, Blastomyces, and Paracoccidioides (1). The family was recently reorganized to include a new genus, Emergomyces, to accommodate several emerging Emmonsia-like fungi causing disseminated disease, mostly among immunocompromised patients worldwide and to address the polyphyletic nature of fungi previously included in the Emmonsia genus (2, 3). Unlike Emmonsia parva and Emmonsia crescens, which cause adiaspiromycosis, fungi within the genus Emergomyces cause disseminated emmonsiosis (or emergomycosis), a multisystem disease with a high case fatality rate (4, 5). In addition, Emergomyces differs from classic Emmonsia species by producing budding yeasts in vivo rather than adiaspores (5, 6). Currently, the genus Emergomyces includes at least three species: the type species, Emergomyces pasteurianus, which appears to have a cosmopolitan distribution; a rarer species, Emergomyces orientalis, reported from China; and Emergomyces africanus, a species endemic to southern Africa (2, 7). The first case of E. pasteurianus was described in an Italian patient with AIDS (8). Thereafter, several reports followed from Spain, China, India, and more recently, a single case from South Africa (2, 9–12). E. orientalis has been reported only from a single immunocompetent Chinese patient (7). At least two other unnamed species exist within Emergomyces, including a strain isolated from lung tissue of a man with rheumatoid arthritis in Germany and two isolates from immunocompromised patients in Canada (2).