PSEUDOMONAS-AERUGINOSA CORNEAL ULCER ISOLATES DISTINGUISHED USING THEARBITRARILY PRIMED PCR DNA-FINGERPRINTING METHOD

Infection of the eye by Pseudomonas aeruginosa can result in corneal i nflammation (keratitis) and ulceration, and permanent decrease in visi on if not successfully treated. We tested for diversity among P. aerug inosa strains from corneal ulcers by the sensitive and efficient 'RAPD ' (for 'random amplified polymorphic DNA') fingerprinting method. This method uses single oligonucleotides of arbitrarily chosen sequence as primers in low-stringency PCR amplification, and results in strain-sp ecific arrays of DNA fragments. Tests of 20 independent P. aeruginosa corneal ulcer isolates yielded 19 different arrays of products with ea ch of three arbitrary primers, indicating that all but two of the stra ins differed from one another. Additional isolates from three patients (infected eye, contact lens or eye drops) yielded fragment patterns t hat were identical to those of the original isolate in each case. Thus , our results demonstrate considerable diversity among P. aeruginosa c orneal ulcer isolates, and suggest that just one clone may predominate in typical infections.