Infectious keratitis following corneal transplantation: A long-term cohort study

Background: To assess the long-term incidence and risk factors for post-keratoplasty infectious keratitis (IK), associated ocular pathogens, and antibiotic resistance profiles.Methods: Cohort study including 2553 consecutive penetrating, endothelial, and anterior lamellar keratoplasties performed between 1992 and 2020. Medical and microbiological records of patients clinically diagnosed with IK were retrospectively reviewed. Main outcome measures: cumulative incidence of IK, infectious agent species, and antibiotics resistance profiles.Results: The average follow-up time after transplantation was 112 +/- 96 months. Eighty-nine IK episodes were recorded; microbiological tests were positive in 55/89 (62%). The cumulated incidence of postoperative IK was 5.50%/10.25% at 10/20 years. The occurrence of at least one episode of IK after transplantation was associated with lower graft survival in the long term (p < 0.0001). Rejection risk (adjusted Hazard Ratio, 2.29) and postoperative epithelial complications (HR, 3.44) were significantly and independently associated with a higher incidence of postoperative IK. Infectious agents included 41 bacteria, 10 HSV, 6 fungi, and 1 Acanthamoeba. The rate of antibiotic resistance was 0% for vancomycin, 13% for fluoroquinolones, 20% for rifamycin, 59% for aminoglycosides, and 73% for ticarcillin. In 41% of cases, patients were under prophylactic topical antibiotics before the infectious episode. Topical antibiotics were significantly associated with increased resistance to penicillin, carbapenems, and aminoglycosides.Conclusion: IK (mainly bacterial) is a frequent complication of corneal transplantation in the long term. Vancomycin and fluoroquinolones can be considered as first-line treatments. Prolonged postoperative antibiotic preventive treatment is not advisable as it may increase antibiotic resistance.