The characteristics of keratomycosis by Beauveria bassiana and its successful treatment with antimycotic agents

Abstract

Hiroko Sonoyama1, Kaoru Araki-Sasaki1, Shigeyasu Kazama1, Tsutomu Kawasaki1, Hidenao Ideta1, Atsuko Sunada2, Seishi Asari2, Yoshitsugu Inoue3, Kozaburo Hayashi41Ideta Eye Hospital, Kumamoto, Kumamoto, Japan; 2Department of Laboratory for Clinical Investigation, Osaka University Hospital, Suita, Osaka, Japan; 3Division of Ophthalmology and Visual Science, Department of Medicine of Sensory and Motor Organ, Tottori University, Yonago, Tottori, Japan; 4Immunology and Virology Section Lab, Immunology, NEI, NIH, Bethesda, MD, USAAbstract: Clinical findings and treatment of keratomycosis caused by Beauveria bassiana, an entomopathogenic filamentous fungus, are described for an 80-year-old woman, who was referred to the hospital for ocular pain and redness on the 9th day after an ocular injury caused by the frame of her glasses. She had a long history of recurrent diabetic iritis and continuously used topical antibiotics and corticosteroids. At her first visit, a slit-lamp examination indicated a corneal ulcer confined within the superficial stromal layer, along with a slight infiltration and edema. Only a very few inflammatory cells were seen in the anterior chamber. Direct microscopic examination of corneal scrapings revealed septate fungal hyphae with zig-zag rachis and budding that was subsequently identified as B. bassiana by slide culture. Topical voriconazole with miconazole, pimaricin and oral itraconazole were effective and the lesion disappeared leaving only a mild scar at 2 months. The sensitivity of B. bassiana to various antimycotic agents was confirmed by broth microdilution, agar dilution with the Clinical Laboratory Standard Institute standard, and a disk method using topically applied concentrations. B. bassiana, which exhibits a characteristic appearance in smears and causes superficial keratomycosis, is sensitive to voriconazole with miconazole, pimaricin, and itraconazole.Keywords: Beauveria bassiana, keratomycosis, filamentous fungus, voriconazole, corneal infection