An epidemic outbreak of Malassezia folliculitis in three adult patients in an intensive care unit: a previously unrecognized nosocomial infection.

BACKGROUND: Malassezia is a lipophilic fungus commonly found in normal human skin. Infection of the hair follicle by Malassezia furfur occurs in patients with predisposing factors such as diabetes or immunosuppression, or who are undergoing antibiotic treatment. Malassezia furfur folliculitis is an infrequent nosocomial infection which may be associated with fomite transmission.

METHODS: We reviewed the clinical files of three adult patients from an intensive care unit (ICU) who simultaneously developed folliculitis through Malassezia infection. We specifically analysed predisposing factors, possible transmission modes, characteristics of skin lesions, results of biopsies and cultures, treatment, and patient outcome.

RESULTS: The three male patients were in neighboring beds and they all had factors that predisposed them to underlying immunosupression. Simultaneously, and within hours of each other, they developed erythematous follicular papules and pustules on the face and chest. The skin biopsies revealed an acute folliculitis with abundant round to oval yeasts of up to 5 microm in diameter. Stains for fungi (Schiff's peryodic acid, Grocott and silver methenamine) revealed numerous unipolar budding yeasts without hyphae, consistent with M. furfur. Conventional cultures were negative. The diagnosis of folliculitis by M. furfur was established and antifinigal treatment initiated, with adequate outcome of the dermatosis. After this outbreak, the aseptic and hygienic measures of the health care personnel of the ICU were reviewed and corrected.

CONCLUSIONS: The simultaneous emergence of this superficial infection by M. furfur suggests fomite participation. This dermatomycosis is an infrequent nosocomial infection in adults, which to our knowledge has not been previously reported.