Metarrhizium anisopliae as a cause of sinusitis in immunocompetent hosts

Metarrhizium anisopliae is a common pathogen of insects and has even been u sed to control insect populations, It is rarely isolated from human or anim al sources, but recently, there have been three reported cases of disease, two in humans and one in a cat. We present our experience with five isolate s from human sources, including two that were the apparent causes of two ca ses of sinusitis in immunocompetent hosts. The first patient was a 36-year- old male with frontal and ethmoid sinusitis, and the second was a 79-year-o ld female with chronic sinusitis. Both patients underwent surgery, and path ology of the surgical specimens revealed branching hyphae. Cultures grew on ly Metarrhizium species. Neither patient received antifungal therapy, and b oth did well postoperatively, The other three isolates were cultured from b ronchoalveolar lavage specimens but were not felt to be clinically signific ant. Antifungal susceptibility testing using the National Committee for Cli nical Laboratory Standards macrobroth method revealed that all isolates wer e resistant to amphotericin B, 5-flucytosine, and fluconazole, Itraconazole and newer azole compounds were more active. Metarrhizium species may cause disease in humans, even those without evidence of immunosuppression, and a re apparently highly resistant to amphotericin B in vitro.