Changes in the etiology of fungal keratitis in Central China over a period of 25 years

Objective  To analyze changes in the etiological profile of fungal keratitis (FK) in Central China in the past 25 years.

Methods  A retrospective study was performed. Data from 37 665 patients with corneal ulcers whose specimens were examined in the microbiology laboratory of Henan Eye Hospital between January 1, 2001 and September 30, 2025 were collected. Epidemiological characteristics, causative fungal genera, changes in the etiological spectrum, and antifungal susceptibility were analyzed. The study adhered to the Declaration of Helsinki and was approved by the Medical Ethics Committee of Henan Eye Hospital (No. HNEEC-2025[38]). Because this study involved only retrospective analysis of existing clinical records and laboratory data, without any interventional procedures or disclosure of personal information, the requirement for informed consent was waived.

Results  The fungal positivity rate of direct microscopic examination of corneal scrapings was 50.88% (19 164/37 665). Among 11 231 patients with FK, 7 227 were male, and 4 004 were female, with a male-to-female ratio of 1.80∶1. Right-eye involvement was recorded in 5 656 cases and left-eye involvement in 5 564 cases. A history of accidental ocular trauma was reported in 50.40% (5 660/11 231) of patients. The mean age of patients was (54.00±13.98) years, with most patients aged 40 to 69 years. The number of visits for infectious keratitis and the fungal culture positivity rate were higher from September to December in a year, with the peak occurring in October. Among 11 231 fungal isolates, Fusarium spp. accounted for 43.30%(4 863/11 231), Aspergillus spp. for 27.01%(3 033/11 231), and Alternaria spp. for 16.77% (1 883/11 231). In the etiological spectrum of FK, the proportion of Fusarium spp. showed a decreasing trend, whereas that of Aspergillus spp. showed an increasing trend and ranked first among the causative genera for the first time in 2011. The proportion of Alternaria spp. showed a fluctuating but gradually increasing trend. The greatest change in the distribution of causative fungal genera occurred in 2013. Antifungal drug susceptibility test showed that Fusarium, Aspergillus, and Alternaria spp. all had relatively high susceptibility rates to voriconazole. Fusarium and Alternaria spp. showed relatively high susceptibility to natamycin, whereas Aspergillus spp. showed relatively low susceptibility to natamycin. All three genera showed low susceptibility rates to amphotericin B, ketoconazole, and fluconazole.

Conclusions  In the Central China, FK predominantly affects middle-aged and elderly men, occurs mainly in autumn, and is most commonly associated with accidental ocular trauma. Fusarium spp. remains the most common causative genus, and the greatest change in fungal genus distribution was in 2013. The three major fungal genera show the highest susceptibility to voriconazole.