Microbial keratitis in the subtropical region of Korea: a comprehensive 12-year retrospective review at a single referral center.

Abstract

To investigate the epidemiological characteristics and clinical outcomes of culture-proven bacterial and fungal keratitis at a single tertiary referral centre on Jeju Island, South Korea. A retrospective study design. Data from a solitary referral centre on Jeju Island spanning January 2011 to December 2022. Among the 245 patients clinically diagnosed with infectious microbial keratitis, 110 individuals had culture-positive results. The primary outcome was the identification of causative microbial profiles and epidemiological characteristics, while the secondary outcome was the correlation of these factors with treatment outcomes. Of 245 patients, 110 (44.9%) had culture-positive infectious keratitis, showing 69 bacterial, 32 fungal, 4 superimposed bacterial and 5 cases with coinfection by bacteria and fungus. The most common pathogen was <i>Pseudomonas</i> species in 14.4% of the bacterial keratitis cases, followed by <i>Staphylococcus epidermidis</i> (9%), <i>Staphylococcus aureus</i> (8%) and Moraxella species (7%). The total treatment success rate for bacterial keratitis was 67.5%. The frequency of methicillin-resistant <i>Staphylococcus</i> on Jeju Island did increase during the study period. Fusarium species had the highest incidence at 22.2%, followed by <i>Candida</i> (16.7%) and <i>Colletotrichum</i> species (11.1%). 56.7% of fungal keratitis patients were successfully treated. An initial large corneal lesion (>3 mm) showed a statistically significant association with treatment failure. The incidence of <i>Moraxella</i> and <i>Colletotrichum</i> species in our study was higher than that reported in other districts with different climates and environments. The results reported here reflect the unique environmental features of Jeju Island, characterised by high humidity and temperatures.