Post-traumatic bacterial keratitis--a microbiological prospective clinical study

The aim of this study was to define the microbiological and clinical profile of traumatic bacterial keratitis, the management and outcome of this disease.

The patients with traumatic bacterial keratitis were prospectively enrolled from 1 June 2004 to 30 June 2006. Clinical features (age, risk factors, visual acuity, corneal ulcer size), microbiological profile, management and outcomes were analyzed.

The 68 consecutive patients were analyzed. Corneal scraping was performed in 96% of cases and in 86, 7% it was positive. 76% of the infections involved Gram positive bacteria, 14% involved Gram negative bacteria, and 8, 8% were polymicrobial. The most commonly isolated bacteria was Staphylococcus epidermidis - 41, 7%. Gram negative bacteria were associated with severe anterior chamber inflammation (p=0.003), as well as greater surface of infiltrates (p=0.04). Antimicrobial treatment was changed on the basis of culture results in 9 cases (13, 2%). 95, 5% of ulcers resolved with treatment, but only 75% of patients had visual acuity better than the level at admission, and 4, 4% had poor visual outcome with indication for corneal transplant.

Infectious keratitis is an important cause of ocular morbidity. Ocular trauma represents the main risk factor for bacterial keratitis. The ulcer size was statistical significantly correlated with patient's age and also the most important predictor of a positive culture result. Fluoroquinolones appear to be the first choice therapy, but based upon these in vitro studies, some strains may be resistant.