Exserohilum infections: review of 48 cases before the 2012 United States outbreak

Exserohilum species are soilborne fungi that have been uncommon causes of human disease. The ongoing outbreak in the United States warrants improved understanding of this pathogen. We systematically reviewed all cases of Exserohilum spp. infections published before the outbreak in 2012 in order to provide a better understanding of the organism and its wider spectrum of human disease. Cases of Exserohilum infections were retrieved by searching PubMed. Demographic data, underlying conditions, microbiology, clinical manifestations, therapy, and outcome were recorded and analyzed. Forty-eight evaluable cases were identified from 1975 to 2012. The number of reported cases increased more than twofold during the study period (P < 0.01). Most cases occurred in the southern United States, India, and Israel. Median age of patients was 25 years, with a male predominance. Most infections were due to E. rostratum (60.4%), followed by E. longirostratum (6.3%) and E. mcginnisii (2%), while 31.3% were unidentified species. The most frequent underlying conditions were immunosuppression (27.2%), trauma (16.6%), and atopy (12.5%). Exserohilum disease manifested as systemic (73%), cutaneous (25%), corneal (16.7%), and subcutaneous (10.4%) infection. Antifungal therapy consisted mainly of amphotericin B (44%) alone or combined with a triazole. Surgery was used in 48% of cases and was combined with antifungal therapy in 31%. The all-cause mortality was 23%, which was higher in patients with preexisting immunosuppression (56.2%; odds ratio 15.4; 95% confidence interval, 2.7-88.6). This review of the pre-outbreak reported cases highlights several aspects of epidemiology, clinical presentation, risk factors, and management of this unusual pathogen.