Clinical Features and Antibiotic Susceptibility of Culture-proven Infectious Keratitis: a Multicenter 10-year Study

Purpose: To analyze the clinical manifestations of culture-proven infective keratitis patients over a recent 10-year period. Methods: We retrospectively reviewed the medical records of 956 cases of infective keratitis between January 2008 and December 2017 at eight tertiary hospitals. The study was performed to analyze the risk factors, causative microbial organisms, therapeutic outcomes, and prognosis. Results: The most common risk factor of keratitis was trauma (33.2%). Initial visual acuity (V/A) was finger count or less in 449 eyes (47.0%). The common location of keratitis was central, and the size was 4 mm(2) or less. Hypopyon was observed in 295 eyes (30.9%). Of the 1,039 cultured isolates, 443 (42.6%) grew Gram-negative bacteria with the most common being Pseudomonas aeruginosa. The most prevalent Gram-positive bacteria was Staphylococcus epidermidis, and fungi was Fusarium species. Surgical treatments were performed in 201 eyes (21.0%), followed by amniotic membrane transplantation (66 eyes) and evisceration (44 eyes). Final V/A was 20/100 or more in 422 eyes (44.1%). Gram-positive organisms were highly susceptible to moxifloxacin and vancomycin, and Gram-negative organisms were highly susceptible to levofloxacin and ceftazidime. An increase in resistance to these antibiotics was detected for Enterococcus and Pseudomonas. Conclusions: In South Korea, infective keratitis occurs frequently in eyes with trauma. Staphylococcus epidermidis, Pseudomonas aeruginosa, and Fusarium species are commonly identified etiologies of microbial keratitis. The appropriate administered medical and surgical treatments of suspected infectious keratitis can lead to visual improvement with particular care taken to minimize infection related to resistant bacteria and fungal microbes as needed. An initial V/A of 0.02 or less, the presence of hypopyon, age of 65 years or more, and a central lesion were associated with poor clinical outcome of bacterial keratitis. Age of 70 years or more was a significant risk factor for poor clinical outcome of fungal keratitis.