Breakthrough zygomycosis and voriconazole.

cines and the template described in An-derson and Hanson [2]. Blower falsely claims (e.g., see [3], p. 118) that her 1993 and 1994 articles included , to quote, " the first transmission model of HIV vaccines to assess the potential epidemic-level impact of imperfect vaccines. " This is incorrect—the 1991 Nature article by Anderson et al. was the first. To the Editor—Zygomycosis is an inva-sive fungal infection caused by various members of the class Mucorales and usually occurs in patients with ketoacidotic diabetes or hematological disorders. It most commonly occurs in patients with acute leukemia or lymphoma who develop neutropenia as a result of malignan-cy or chemotherapy and in transplant recipients receiving immunosuppressive treatment [1]. Recently, some reports have suggested an increase in the incidence of zygo-mycosis in association with prophylactic voriconazole (VRC) use in immunosup-pressed patients [2–5]. In a recent article , Kontoyiannis et al. reported the results of an observational matched case-control study comparing consecutive patients with zygomycosis and 2 control groups, patients without an invasive mold infection and patients with invasive aspergillosis [6]. The authors identified 27 patients with zygomycosis; 13 (48%) of them had received previous VRC pro-phylaxis. In a multivariate analysis comparing the patients with zygomycosis and the patients without an invasive mold infection , VRC prophylaxis, diabetes, and malnutrition were found to be independent risk factors for zygomycosis. When the patients with zygomycosis and the patients with invasive aspergillosis were compared, VRC prophylaxis was found to be the most relevant factor favoring the onset of zygomycosis. Kontoyiannis et al. suggest that the increased incidence of zygomycosis might reflect the increasing and prolonged use of oral VRC versus parenteral agents with activity against Zygomycetes. However, it is important to determine whether the increased incidence of zygomycosis is due solely to an increase in oral VRC use or can also be attributed to improvement of the tools of diagnosis and to increased attention to this infection by physicians. Certainly, an increase in breakthrough infections by opportunistic pathogens is a concern with any antimicrobial agent— VRC is no exception—and it is true that the increased incidence of zygomycosis stands in contrast to the previous breakthrough infections seen when fluconazole or itraconazole were used for prophylaxis [7, 8]. However, an increase in the incidence of zygomycosis over the past 20 years has already been described [9]. In a multicenter retrospective survey conducted over a 15-year period (1987– 2001) …