Miscellaneous Opportunistic Fungi
Many yeasts and molds can cause opportunistic, even life-threatening infections in immunocompromised patients. These infections only rarely affect immunocompetent people. Yeasts tend to cause fungemia as well as focal involvement of skin and other sites.
Blastoschizomyces capitatus and Trichosporon sp (including T. ovoides, T. inkin, T. asahii, T. mucoides, T. asteroides, and T. cutaneum) affect neutropenic patients in particular. Among Trichosporon, T. asahii is the most common cause of disseminated disease. The name T. beigelii, now obsolete, was formerly used for all or any of these Trichosporon sp.
Malassezia furfur fungemia typically affects infants and debilitated adults receiving lipid-containing IV hyperalimentation infusions.
Penicillium marneffei was recognized as an opportunistic invader in Southeast Asian patients with AIDS, and cases have been recognized in the US. P. marneffei skin lesions may resemble molluscum contagiosum.
Especially in neutropenic patients, various environmental molds, including species of Fusarium and Scedosporium, both of which are becoming more frequent, can cause focal vasculitic lesions mimicking invasive aspergillosis. Fusarium in particular may grow in routine blood cultures from patients with disseminated infection.
Specific diagnosis requires culture and species identification and is crucial because not all of these organisms respond to any single antifungal drug. For example, Scedosporium sp are typically resistant to amphotericin B. Optimal regimens of antifungal therapy for each member of this group of fungal opportunists must be defined.