Zygomycosis in a Tertiary‐Care Cancer Center in the Era of Aspergillus‐ Active Antifungal Therapy: A Case‐Control Observational Study of 27 Recent Cases

BACKGROUND: Anecdotal evidence suggests a rise in zygomycosis in association with voriconazole (VRC) use in immunosuppressed patients. METHODS: We performed prospective surveillance of patients with zygomycosis (group A; n = 27) and compared them with contemporaneous patients with invasive aspergillosis (group B; n = 54) and with matched contemporaneous high-risk patients without fungal infection (group C; n = 54). We also performed molecular typing and in vitro susceptibility testing of Zygomycetes isolates. RESULTS: Nearly all patients with zygomycosis either had leukemia (n = 14) or were allogeneic bone marrow transplant recipients (n = 13). The Zygomycetes isolates (74% of which were of the genus Rhizopus) had different molecular fingerprinting profiles, and all were VRC resistant. In multivariate analysis of groups A and C, VRC prophylaxis (odds ratio OR, 10.37 95% confidence interval [CI], 2.76-38.97]; P = .001), diabetes (OR, 8.39 95% CI, 2.04-34.35; P = .003), and malnutrition (OR, 3.70 95% CI, 1.03-13.27; P = .045) were found to be independent risk factors for zygomycosis. Between patients with zygomycosis (after excluding 6 patients with mixed mold infections) and patients with aspergillosis, VRC prophylaxis (OR, 20.30 95% CI, 3.85-108.15; P = .0001) and sinusitis (OR, 76.72 95% CI, 6.48-908.15; P = .001) were the only factors that favored the diagnosis of zygomycosis. CONCLUSIONS: Zygomycosis should be considered in immunosuppressed patients who develop sinusitis while receiving VRC prophylaxis, especially those with diabetes and malnutrition.