Diagnostic information Profiling and Evaluation of Causative Fungi of Fungal Keratitis Using High-throughput Internal Transcribed Spacer Sequencing

Early and accurate diagnosis is essential for the targeted management of fungal keratitis (FK), which is one of the major blinding eye diseases worldwide. To elucidate the diagnostic information of high-throughput internal transcribed spacer (ITS) sequencing for identifying causative fungi of FK, 38 patients who were highly suspected of having FK were included in this research. In vivo confocal microscopy, potassium hydroxide smear, and fungal culture were performed to diagnose FK. Culture and ITS sequencing were used to identify causative fungi. We hypothesized that the dominant genus was the result of pathogen identification by ITS sequencing. Thirty-five patients were eventually diagnosed with FK, with fungal pathogens found by confocal microscopy in 27 patients (77.14%), by smear examination in 27 patients (77.14%), by culture in 25 patients (71.43%), and by ITS sequencing in 26 patients (74.29%). Eight causative fungal genera were determined by ITS sequencing, while five causative fungal genera were identified based on the morphology of the cultured pathogens. The results of ITS sequencing and culture were coincident in 10 patients with FK (28.57%). It is concluded that ITS sequencing, to some extent, challenged fungal culture and might be an optional complement in identifying fungal pathogens in corneas.