Equine Fungal Keratitis due to <i>Cladorrhinum bulbillosum</i>

OBJECTIVE: To describe the case details and treatment of an equine fungal keratitis case caused by Cladorrhinum bulbillosum. ANIMAL STUDIED: A 14-year-old Bashkir Curly gelding with a complicated corneal ulcer of the left eye. PROCEDURES: Corneal cytology was performed, and intraoperative samples were collected for polymerase chain reaction and for aerobic and mycologic cultures. Under general anesthesia, an inferior eyelid subpalpebral lavage system (SPL) was placed to facilitate postoperative therapy. Anterior stromal keratectomy was performed followed by cryotherapy of the keratectomy bed. A biological scaffold graft was secured within the defect and temporary tarsorrhaphy performed to protect the surgical site. Postoperatively, the horse received systemic anti-inflammatories and topical medications via SPL: antibacterials (ofloxacin, cefazolin), antifungals (voriconazole, luliconazole), and anticollagenase (serum) as well as atropine. Reevaluations were performed every 2-3 weeks until discontinuation of medications. RESULTS: Following surgical and medical management, the horse showed improvement with resolution of the corneal ulcer over an 8-week treatment period. Next-generation sequencing identified C. bulbillosum as the predominant organism, and fungal culture supported filamentous fungal infection. CONCLUSION: C. bulbillosum infection caused equine fungal keratitis in this case. The use of topical voriconazole and luliconazole, combined with surgical intervention (keratectomy, cryotherapy, bio scaffold graft), resulted in a good response. The corneal ulcer healed well with minor scarring over 8 weeks following surgical intervention. To the authors' knowledge, this was the second report of equine fungal keratitis caused by C. bulbillosum. This case highlights the utility of next-generation DNA sequencing and multimodal treatment with adjunctive contemporary therapies.