Coniochaeta hoffmannii and mutabilis Invasive Fungal Keratitis: A Case Series and Literature Review

Abstract

To describe 2 Coniochaeta species (Coniochaeta hoffmannii and Coniochaeta mutabilis) as rare causes of invasive fungal keratitis resulting in enucleations and to provide a review of ocular infections caused by the genus Coniochaeta and underscore changes to its classification over the past 3 decades, which may clarify previous reports with outdated nomenclature. This is a small case series from a single academic institution (Casey Eye Institute) with a summary of the literature. The first case describes a 53-year-old man who had an indolent but persistent anterior chamber reaction after repair of a penetrating nail injury. Cultures from a second penetrating keratoplasty identified C. hoffmannii, which was determined through phenotypic characterization and DNA sequencing. Despite surgical management, cultures were persistently positive for C. hoffmannii. Two years post-injury, he developed a funnel retinal detachment with proliferative vitreoretinopathy and elected for enucleation. The second case describes a 54-year-old woman with poor contact lens hygiene with a presumed filamentous fungal keratitis that remained refractory to topical natamycin. Broad-range polymerase chain reaction of an anterior chamber aspirate identified C. mutabilis. Therapeutic keratoplasty was performed for worsening infection; however, because of intractable pain, she elected for enucleation. Pathology from the enucleation specimen demonstrated persistent, but sparse, fungal elements. This is the first case series characterizing ocular infections caused by Coniochaeta, a rare cause of invasive fungal keratitis resulting in devastating outcomes for our patients. Identification of Coniochaeta was initially difficult by traditional culturing techniques, and subsequent molecular diagnostic testing proved useful in detection. Our review of ocular Coniochaeta clarifies previous reports with outdated nomenclature.