BACKGROUND: The identification of the causative pathogen in infectious keratitis is possible in only 60% of the cases. The aim of this study was to show if this number increases by the use of PCR. PATIENTS AND METHODS: In a series of 16 eyes with infectious keratitis corneal specimens were collected for culture and PCR. Serology (HSV, VZV, and Borrelia) was performed in all eyes, with exception of the 4 eyes presenting an acute form of keratitis, which obviously was bacterial origin. RESULTS: In all 4 cases of acute keratitis the causative pathogen (Pseudomonas aeruginosa) was detected by both culture and PCR. Of the remaining 12 eyes PCR was capable to identify the causative pathogen in 11 eyes. In 3 eyes herpes simplex virus was detected, in 3 eyes Moraxella catharalis, in 2 eyes Borrelia burgdorferii, in 2 eyes varizella zoster virus, and in 1 eye Bartonella henselae. Culture was positive in only 2 eyes, infected by Moraxella catharalis. CONCLUSIONS: PCR is a useful supplement in the microbiological diagnostic of infectious keratitis, in particular if only a small amount of pathogens are available (non-acute form) or if the eye has been treated by antibiotics prior to the microbiological diagnostic.
