Predictors Of Infectious Corneal Ulcer Outcomes In A Real-World Cohort: Clinical Risk Factors, Microbiology, And Antimicrobial Resistance

To characterize the epidemiology, microbiological spectrum, and antimicrobial resistance of infectious corneal ulcers in a Northern Portugal referral center and to identify predictors of severe structural outcomes in real-world practice.

Ophthalmology referral center in Northern Portugal; consecutive infectious corneal ulcer episodes sampled for microbiology between 2014 and 2025.

Retrospective observational cohort study of consecutive infectious corneal ulcer episodes undergoing microbiological sampling (2014–2025). Baseline demographics, ocular and systemic risk factors, clinical severity markers (ulcer location, hypopyon), culture results, organism groups, antimicrobial susceptibility and initial empiric therapy were recorded. The primary outcome was severe structural failure (corneal perforation and/or evisceration). Secondary outcomes included central corneal scarring and hospitalization. Predictors of severe outcome were assessed using multivariable logistic regression.

The study included 206 episodes (205 patients; mean age 54.6 ± 20.7 years). Culture was positive in 49.0%. Among culture-positive episodes, bacteria predominated (76.2%); the most frequent identified pathogens included Pseudomonas aeruginosa and Cutibacterium acnes, alongside HSV-1, coagulase-negative staphylococci, and Corynebacterium spp. Resistance was uncommon among isolates with available susceptibility data (fluoroquinolone 12%, aminoglycoside 9.1%, cephalosporin 5.9%); multidrug resistance occurred in 4.7%. Severe outcome occurred in 8.4% of episodes with available data. In multivariable analysis, hypopyon (aOR 6.85), systemic immunosuppression (aOR 4.89), and diabetes mellitus (aOR 2.50) independently predicted severe outcome.

In this cohort, severe corneal ulcer outcomes were primarily driven by baseline inflammatory severity and host vulnerability (hypopyon, immunosuppression, diabetes), while antimicrobial resistance and MDR were infrequent. Early risk stratification using these clinical and systemic factors may guide earlier escalation and closer follow-up, alongside ongoing local resistance surveillance.