Fungal keratitis caused by Beauveria bassiana: drug and temperature sensitivity profiles: a case report

Abstract

BackgroundBeauveria bassiana is an entomopathogenic fungus and is a rare cause of keratitis. We present a case of fungal keratitis caused by B. bassiana that was diagnosed by in vivo confocal microscopy and in vitro corneal cultures. In addition, we determined the temperature- and drug-sensitivities of the isolated strain of B. bassiana.Case presentationA 59-year-old Japanese man with a 2-month history of keratitis was examined by slit-lamp biomicroscopy, in vivo confocal microscopy, and histology and cultures of corneal scrapings. The corneal scrapings were used to determine the minimal inhibitory concentrations of different antifungal drugs and also to determine the temperature-sensitivity. In vivo confocal microscopy and histological examinations showed filamentous fungal keratitis. The characteristics of the fungal growth indicated that the keratitis was caused by B. bassiana. The keratitis responded poorly to systemic and topical voriconazole and to natamycin ointment. However, it was resolved after changing the natamycin to micafungin combined with surgical debridement. The isolated strain was sensitive to itraconazole, miconazole, micafungin, voriconazole, and resistant to flucytosine and fluconazole. It was moderately sensitive to amphotericin B, and natamycin. After 7 days in culture, the isolate grew small white colonies at 25°C, very small colonies at 35°C and 37°C.ConclusionThe drug-sensitivity and temperature-sensitivity profiles of B. bassiana should be helpful in the treatment of B. bassiana keratitis. Therapeutic surgery may be helpful for mycotic keratitis poorly responsive to medical therapy alone.

Fungal keratitis: study of increasing trend and common determinants

“…[ 12 ], Acremonium spp. [ 13 ], Cryptococcus albidus [ 14 ]), Pythium insidiosum [ 15 ], Beauveria bassiana [ 16 ], Paecilomyces [ 17 ], Cunninghamella spinosum [ 18 ], Scedosporium apiospermum [ 19 ]), Rhodotorula mucilaginosa [ 20 ], Cylindrocarpon lichenicola [ 21 ], Cladorrhinum bulbillosum [ 22 ]. Lophotrichus species were isolated from the necrotic corneal sample complicating fungal keratitis after dog paw traumatic injury [ 11 ].…”

Fungal Keratitis Due to Beauveria bassiana in a Contact Lenses Wearer and Review of Published Reports

“…Histopathologically, B. bassiana grows slowly in corneal cells [12], and it generally does not invade the anterior chamber which, according to some authors, may be due to its inability to grow at 35-37°C [10]. In the case reported, B. bassiana did invade the anterior chamber, which might be the result of a reactive uveitis caused by an existing epithelial lesion or by the concomitance of two different infections.…”

“…As in the case reported, antifungal therapy requires adjunct debridement surgery to treat the lesions [1,6,10]. However, topical and systemic antifungal therapy has been reported to be effective in some cases, especially if it includes natamycin [7] and azoles (voriconazole, itraconazole) [8].…”

“…Keratitis due to B. bassiana is an extremely rare corneal infection that is usually resistant to local and [10]. Mycotic keratitis is a clinical entity that requires early diagnosis to prevent severe complications such as corneal perforation or endophthalmitis.…”

Histological Effects of Intravitreal Injection of Antifungal Agents in New Zealand White Rabbits: An Electron Microscopic and Immunohistochemical Study

“…In a clinical case reported by Monden et al, topical and intravenous administration of micafungin was found to be effective and safe in the treatment of fungal keratitis due to Pestalotiopsis clavispora after prior treatment with topical voriconazole and pimaricine in recurrence of infection [ 72 ]. Micafungin in combination with voriconazole has been shown to be effective in treating fungal keratitis caused by Beauveria bassiana when treatment with topical and systemic voriconazole and topical natamycin has not yielded favorable clinical results [ 73 ]. Treatment success was attributed to the synergistic effect of voriconazole and micafungin and surgical clearance.…”