Increasing incidence of mucormycosis in a large Spanish hospital from 2007 to 2015: Epidemiology and microbiological characterization of the isolates

We studied 19 cases of proven/probable mucormycosis diagnosed from 2007 to 2015 in our hospital and assessed the microbiological characteristics of the isolates. We recorded the incidence of mucormycosis and clinical and microbiological data of infected patients. Isolates were identified to molecular level and tested for their antifungal susceptibility to azoles, amphotericin B, and liposomal amphotericin B according to the CLSI M-38 A2 procedure. The incidence of mucormycosis in cases/100,000 hospital admissions during 2007-2015 increased significantly with respect to that reported in 1988-2006 (3.3 vs. 1.2; P<0.05). Patients mainly had hematological malignancies (52.6%) and/or trauma/surgical wounds (52.6%) and had received antifungal agents before the diagnosis of mucormycosis in 68% of cases. Diagnosis was by isolation (n = 17/19) and/or direct staining (n = 17/18) of Mucorales fungi in clinical samples. Identification was by panfungal PCR in patients with negative results in culture and in direct staining. The microorganisms identified were Lichtheimia spp. (42%), Rhizopus spp. (21%), Cunninghamella bertholletiae (16%), and others (21%). Liposomal amphotericin B was always more active than the other drugs against all the microorganisms except C. bertholletiae. All patients received antifungal treatment with 1 or more antifungal agents, mainly liposomal amphotericin B (17/19). Mortality was 47.4%, although this was significantly lower in the 11 patients in whom debridement was performed (18% vs. 87.5%) (P = 0.015). The incidence of mucormycosis has risen in recent years. The proportion of cases with soft tissue involvement was high, and Lichtheimia was the most frequently involved species. The highest antifungal activity was observed with liposomal amphotericin B.