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.