Atypical Fungal Sclerokeratitis

Abstract

Metarrhizium anisopliae is an extremely rare cause of ocular infection, and this report represents the first case of sclerokeratitis caused by this pathogen worldwide. Although found to be clinically sensitive to antifungal agents in previously reported cases of keratomycosis alone, it was found to be resistant to multiple antifungal agents with devastating consequences with the presence of scleral involvement.

Fungal keratitis caused by Metarhizium anisopliae complex

“…M. anisopliae has been used as a biological control agent of insects in many countries globally [5]. It was not believed to adversely affect humans because it is unable to grow at human body temperature [6]; however, it has been recently reported as pathogenic to humans. There have been four reported cases of M. anisopliae causing ocular infection [5], [6], [7], [8] The first report of mycotic keratitis caused by M. anisopliae was in 1997, in an 18-year-old Colombian man [7]. Another case was reported 4 years later in a healthy 36-year-old female in the United States [8]. Both patients were treated successfully with natamycin eye drops.…”

Pediatric Metarrhizium anisopliae keratitis

“…4 A 52-year-old Australian woman presented with a painless red eye due to a 7 Â 4.5 mm M. anisopliae corneal ulcer and adjacent scleral necrosis. 5 Despite a 3-week hospitalization and treatment with topical natamycin, amphotericin B, voriconazole, chlorhexidine, and povidone iodine, the cornea perforated requiring penetrating keratoplasty to eradicate infection. 5 Five nonocular cases of M. anisopliae infection have been reported involving the skin and sinuses.…”

“…5 Despite a 3-week hospitalization and treatment with topical natamycin, amphotericin B, voriconazole, chlorhexidine, and povidone iodine, the cornea perforated requiring penetrating keratoplasty to eradicate infection. 5 Five nonocular cases of M. anisopliae infection have been reported involving the skin and sinuses. [6][7][8][9] Topical natamycin and amphotericin B are polyene antifungals that have been recommended for superficial filamentous fungal keratitis, whereas deeper stromal lesions may require systemic antifungals or keratoplasty.…”

“…anisopliae is considered safe to humans because optimal growth occurs at 25 C, well below human body temperature; however, M. anisopliae may survive temperatures up to 35-36 C. 5 Normal corneal temperature ranges from 32.50 -36.50 C and is lowest centrally and highest peripherally. 12 Further study is warranted to determine whether corneal temperature gradient facilitates infection.…”

“…Eight cases of human infection by M. anisopliae have been previously reported, including 3 ocular infections. [3][4][5][6][7][8][9] An 18-year-old Columbian man with a painless round M. anisopliae corneal ulcer was cured with topical natamycin 5% and silver-sulfadiazine 1%. 3 A 36-year-old American female contact lens wearer with mild eye irritation attributable to a 2.5 mm round paracentral M. anisopliae corneal ulcer was left with a stromal scar after a 2-month course of topical medications including natamycin 5% and multiple antibacterials.…”