An unusual case of fungal keratitis: Metarrhizium anisopliae

To report a case of fungal keratitis caused by Metarrhizium anisopliae, which to our knowledge is the first reported case in the United States.

Case report.

A 36-year-old female librarian who wore extended-wear soft contact lenses was seen by an ophthalmologist on September 11 for an irritated right eye, and a corneal ulcer was diagnosed. Symptoms increased by September 27, and the patient was referred to another ophthalmologist who cultured the ulcer and had scrapings examined, which were Gram-negative for microorganisms. The patient was referred to one of the authors (W.J.R.). Her exam on October 1 showed vision corrected to 20/25 OD, a 5-mm epithelial defect with a 2.5-mm anterior stromal grayish-type infiltrate, and a quiet anterior chamber; the eye did not appear to be inflamed. The patient was reexamined on October 4 and was noted to have worsening vision. Because the initial cultures remained negative, the patient underwent a corneal biopsy, Gram stain, and cultures on October 6. Scrapings at the time of the biopsy revealed septate hyphal elements, as did the biopsy specimen, and on October 7, the patient was started on a treatment of bacitracin ointment once a day and natamycin 5% every hour. The eye gradually quieted down. A mold growing from the biopsy culture, which had been sent to a reference laboratory in San Antonio, Texas, was identified as M. anisopliae var. anisopliae. The patient was subsequently fitted with a rigid gas permeable lens, which resulted in a best-corrected visual acuity of 20/20, although glare remained a major problem.

Although not previously reported in the United States, M. anisopliae can cause a keratomycosis, and one must consider this common insect pathogen in the differential diagnosis of fungal keratitis.