[A retrospective analysis of infection after corneal transplantation]

We studied retrospectively the background of postoperative infection after corneal transplantation.

We reviewed the records of 753 eyes that had undergone corneal transplantation at Kyoto Prefectural University of Medicine or the Baptist Eye Clinic over a period of 6 years from April 1994 to March 2000. Patients who developed microbial keratitis after corneal transplantation were evaluated for the incidence of infection, age, the interval between transplantation and infection, microbiological etiology, the use of topical steroids, therapy, and complications.

Follow-up after keratoplasty averaged 43.2+/-25.6 months (mean+/-standard deviation). Among 753 eyes examined, microbial keratitis developed in 27 eyes (3.6%), 14 eyes had bacterial, and 13 had fungal infections. The ages at presentation were 51.4+/-21.5 years for bacterial infections, and 66.5+/-11.1 for fungal infections. The time intervals between transplantation and the onset of infection averaged 7.8+/-7.9 months for bacterial infections, and 24.2+/-17.2 for fungal infections. Infections in 7 (50.0%) of the bacterial eyes were caused by methicillin-resistant Staphylococcus aureus (MRSA) or epidermidis (MRSE), and 9 (69.2%) of the fungal infections by yeast type fungus (8 were Candida species). At onset of keratitis, 3 (21.4%) of the bacterial eyes and 6 (46.2%) of the fungal eyes were treated with fluorometholone, and 11 (78.6%) of the bacterial eyes and 7 (53.8%) of the fungal eyes were treated with betamethazone or dexamethasone. The treatment duration until the focus of disappeared was 32.8+/-19.7 days for bacterial eyes, and 74.8+/-56.3 for fungal eyes. Major complications associated with infection included corneal perforation in 2 eyes of both the bacterial (14.3%) and fungal (15.4%) eyes, graft rejection in 4 (28.6%) bacterial eyes and 1 (7.7%) fungal eye, there was no recurrence of infection in the bacterial eyes but there were 3 (23.1%) cases of recurrence in the fungal eyes.

Infection after corneal transplantation is opportunistic. Fungal infections occurred later than bacterial infections. Also in fungal infections, the mean age at presentation was higher and the recurrence of infection was more frequent.