Infectious bacterial keratitis management in a Swedish region: Risk factors, treatment and time-to-resolution

To report treatment patterns, time-to-resolution (TTR) and aetiologies of bacterial keratitis (BK) infections treated in a specialized hospital-based cornea clinic in Sweden.

Retrospective study based on electronic health records screened during the period 2010-2019. The study included only culture-confirmed cases of BK. TTR was defined as the number of days from the sample collection for microbiological culture to the date that the cornea healed. Factors affecting TTR were investigated with Cox regression models.

Contact lens wear and severely ill/blind eye were the most common aetiologies among the 188 patients. Empirical treatment consisted of fluoroquinolones in combination with aminoglycosides in 50% of the patients. Median TTR was 22 days (95% CI: 12, 34) for contact lens-related BK and 90 days (95% CI: 55, 146) in complicated cases with miscellaneous or unknown aetiology. Hazard ratio (HR) for infections in females (HR = 1.93; 95% CI: 1.34, 2.79), contact lens wearers (HR = 2.72; 95% CI: 1.79, 4.14) and infections caused by Gram-positive pathogens (HR = 2.50; 95% CI: 1.50, 4.19) indicated that infections in these categories healed at a faster rate than their reference categories. Patients switching to treatment with chloramphenicol after it was absent in the empirical treatment had a slower rate of healing than those who received chloramphenicol as part of the empirical treatment (HR = 0.58; 95% CI: 0.38, 0.87).

The current study provides unique TTR estimates for BK. The results revealed that age, sex, aetiology, empirical treatment and Gram staining can affect TTR. In our sample, empirical treatment that includes chloramphenicol could potentially reduce TTR. These findings can be used to individualize disease management and prognosis.