Emerging invasive zygomycosis in a tertiary care center: epidemiology and associated risk factors.

Objectives: Invasive zygomycosis is a rare fungal opportunistic disease with a high morbidity and mortality rate, predominantly affecting immunosuppressed patients. Presented herein is our investigation of the epidemiological factors associated with an increasing incidence of the disease at the University of Geneva Hospitals, Geneva, Switzerland, over the past five years.

Methods: This was a retrospective study of the clinical charts and microbiology records of patients with a positive culture for zygomycetes, to evaluate predisposing factors and epidemiological characteristics.

Results: Three of 19 proven/probable invasive infections were diagnosed during 1989-2003, and 16 during 2003-2008. While the number of positive isolates for zygomycetes remained mainly stable, the ratio between invasive infections and colonized patients increased after the introduction of voriconazole and caspofungin in 2003 at our institution (p<0.001). All cases were unrelated and no nosocomial source of exposure or seasonal aggregation was identified. The increase in cases was coincident with an incremented use of voriconazole and caspofungin, and with an increased number of immunosuppressed patients, especially allogeneic bone marrow transplant recipients.

Conclusions: Invasive zygomycosis is an emerging infection at our center and is probably related to an increase in immunosuppressed patients and the wide use of newer antifungals. Changes in antifungal drug prophylaxis and treatment prescription may help to control this emergence.