Recurrent bacterial keratitis

Abstract

Purpose: To investigate the rate of recurrent bacterial keratitis, associated bacteria, and surgical intervention.

Methods: Patients with suspected bacterial keratitis were identified from microbiological requests over a 16-year period between 1995 and 2010. Recurrences and number of surgical interventions were analyzed according to bacterial type.

Results: A total of 2418 patients were included, of whom 2124 (87.84%) had only one episode of keratitis, 294 (12.15%) at least two, 88 (3.63%) at least three, 40 (1.65%) at least four, and 22 (0.91%) five or more episodes. The bacterial isolation rate was 35.74% (SD 9.41%), increasing to 56.01% in patients with two or more episodes. There was an increase in the isolation of Staphylococcus aureus with increasing number of episodes (P = 0.008), and S. aureus occurred more commonly in patients with recurrent disease due to the same bacterial group (P = 0.04). Patients whose recurrent keratitis was associated with S. aureus had a higher rate of requiring subsequent corneal transplantation (7 of 10) compared to those with Enterobacteriaceae (2 of 7), Pseudomonas aeruginosa (2 of 4), streptococci (2 of 5), or coagulase-negative staphylococci (none of 8) (P = 0.02).

Conclusions: S. aureus is particularly associated with recurrent keratitis. Identification and treatment of the possible source of the infection may be necessary to reduce the risk of recurrent disease. The potential for the autocthonous S. aureus colonizing the nasopharynx or conjunctiva or lid margin to be a reservoir for recurrent keratitis suggests that decolonization of S. aureus could be considered as a potential intervention in those patients with recurrent disease.

Keywords: Staphylococcus aureus; bacteria; keratitis; recurrent.