Effects of the COVID-19 Pandemic on Microbial Keratitis: A 5-Year Comparative Study

To report the clinical and microbiological profiles of microbial keratitis and its antimicrobial resistance before, during, and after COVID-19.

This was a retrospective case-note review of all corneal scrape specimens collected from patients with microbial keratitis from January 2018 to December 2023. Case records were analyzed for demographic characteristics, microbiological diagnosis, and antibiograms. All outcome variables were collected, stratified, and compared between 3 periods: the pre-COVID-19 group (January-December 2019), the COVID-19 group (January 2020-December 2022), and the post-COVID-19 group (January-December 2023).

A total of 947 corneal cultures from 947 patients were reviewed. Gram-positive bacteria predominated in all periods, with no significant differences in their distribution. Staphylococcus epidermidis was the most frequently identified organism. Pseudomonas aeruginosa was the most common Gram-negative bacterium, with its incidence significantly lower in the post-COVID period. Fungal infections showed a significant increase in the post-COVID group, with Fusarium sp. being the most common fungus and showing a significant increase in incidence in the post-COVID group.

Despite a stable incidence of microbial keratitis, this study highlights a concerning trend in antibiotic resistance. Although some pathogens became less common, those that persisted have become increasingly difficult to treat. Understanding the clinical and microbiological profiles of microbial keratitis and antimicrobial resistance patterns before and after the COVID-19 pandemic is crucial for informed treatment decisions.