Fungal Keratitis Secondary to Trametes betulina: A Case Report and Review of Literature Joshua S. Hardin . Deanna A. Sutton . Nathan P. Wiederhold . James Mele . Sunali Goyal Received: 23 December 2016 / Accepted: 21 February 2017 Ó Springer Science+Business Media Dordrecht 2017 Abstract Purpose We report the first case of human infection and keratitis secondary to Trametes betulina, a rare filamentous fungus. Methods Clinical examination including external and slit-lamp examination and corneal scrapings with microbiologic evaluation were performed on a patient with chronic allergic conjunctivitis, entropion and a long-standing corneal ulcer resistant to treatment. Results The culture from the corneal scraping revealed a basidiomycetous fungus which was sub- mitted for identification. DNA extraction with sequencing and analysis of the ITS and D1/D2 regions were performed on the isolate and demonstrated 100% similarity to Lenzites betulina/Trametes betulina. Susceptibility testing demonstrated potent in vitro activity of voriconazole (MIC \ 0.03 lg/ml). The patient was treated with voriconazole, and the corneal ulcer and infiltrate resolved. The infection resulted in corneal thinning and a dense central corneal scar. Penetrating keratoplasty was performed 5 months after diagnosis and treatment and revealed stromal scarring without fungal elements. Conclusion This is the first reported case of keratitis caused by Trametes betulina. This organism should be considered in the differential diagnosis for rare filamentous fungal keratitis and its treatment with voriconazole also noted. Keywords Cornea Á Keratitis Á Fungus Á Trametes betulina Á Lenzites betulina Á Basidiomycete Introduction Fungal keratitis represents between 1 and 50% of all cases of culture-proven microbial keratitis, with greater prevalence in developing countries and trop- ical climates [1–3]. It is a corneal infection by fungi which exist naturally in the environment, most com- monly Candida and filamentous types [4, 5]. We present the first reported case of human infection (fungal keratitis) by Trametes betulina. Case A 79-year-old man with a past medical history of prostate cancer, seasonal allergies, asthma, hyperten- sion, and sleep apnea presented to our clinic with a chronic corneal ulcer. His past ocular history included J. S. Hardin (&) Á S. Goyal Jones Eye Institute, University of Arkansas for Medical Sciences (UAMS), 4301 W. Markham St., Little Rock, AR 72207, USA e-mail: jshardin@uams.edu D. A. Sutton Á N. P. Wiederhold Á J. Mele Department of Pathology, University of Texas Health Science Center at San Antonio (UTHSCSA), San Antonio, TX, USA 123 Mycopathologia DOI 10.1007/s11046-017-0128-6