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.
(See also Overview of Fungal Infections.)
Trichosporon species
Trichosporon species, including T. ovoides, T. inkin, T. asahii, T. mucoides, T. asteroides, and T. cutaneum, are yeasts that are often commensals but can cause fatal disseminated infection, particularly in immunocompromised patients (eg, neutropenia). Among Trichosporon species, T. asahii is the most common cause of disseminated disease.
Trichosporon species are notable for their ability to form biofilms on medical devices.
Malassezia species
Malassezia furfur and other Malassezia species (eg, M. globosa) are yeasts that cause tinea versicolor and folliculitis. They can also cause catheter-related fungemia in patients who are receiving parenteral lipids through a central venous catheter. Catheter-related fungemia typically affects infants and debilitated adults receiving lipid-containing IV hyperalimentation infusions.
Microbiology laboratory personnel should be notified when attempting to isolate Malassezia from clinical specimens because special media are required.
Talaromyces marneffei
Talaromyces marneffei is an opportunistic pathogen causing disseminated infection in patients in Southeast Asia who have advanced HIV infection. Cases have been recognized in travelers returning to the United States after visiting that region.
T. marneffei skin lesions may resemble those of molluscum contagiosum.
Fusarium species and Scedosporium apiospermum
Various environmental molds, including species of Fusarium and Scedosporium apiospermum, both of which are becoming more frequent causes of infection, can cause focal angioinvasive vasculitic lesions mimicking invasive aspergillosis.
Fusarium species and S. apiospermum cause superficial infections (eg, keratitis, onychomycosis) in immunocompetent patients and disseminated infections in patients who are severely immunocompromised with prolonged, severe neutropenia and/or severe T-cell immunodeficiency. Fusarium species (unlike Aspergilli) may grow in routine blood cultures from patients with disseminated infection.
Accurate diagnosis requires culture and species identification, which are essential for guiding effective antifungal therapy because of differing resistance profiles. For example, Scedosporium species are typically resistant to amphotericin B. Therefore, optimal antifungal regimens must be tailored to each specific pathogen within this group of opportunistic fungi.species are typically resistant to amphotericin B. Therefore, optimal antifungal regimens must be tailored to each specific pathogen within this group of opportunistic fungi.
Voriconazole is considered the medication of choice for both Voriconazole is considered the medication of choice for bothFusarium and S. apiospermum.
Drugs Mentioned In This Article
