DIAGNOSIS OF FUSARIUM KERATITIS IN AN ANIMAL-MODEL USING THE POLYMERASE-CHAIN-REACTION

Aims/background-The purpose of this study was apply the polymerase cha in reaction (PCR) to develop a sensitive, specific, and rapid test to diagnose Fusarium keratitis. Fusarium is the most common cause of fung al corneal infection in some parts of the world. It is often difficult to establish that a keratitis is due to fungal infection. Methods-Fus arium solani keratitis was induced in three eyes of three rabbits by i njection of a suspension of the fungus into the anterior corneal strom a. In one rabbit the contralateral eye served as a control. From four to 28 days after inoculation, the corneas were scraped for culture, th en scraped and swabbed for PCR analysis. The PCR was performed with pr imers directed against a portion of the Fusarium cutinase gene, and th e presence or absence of this amplified target sequence was determined by agarose gel. Results-The amplified DNA sequence was detected in 25 of 28 samples from the corneas infected with Fusarium, for a sensitiv ity of 89%. Only three of the 14 samples from these eyes with Fusarium keratitis were positive by culture, for a sensitivity of 21%. Seven o f eight control samples were negative by the PCR based test, for a spe cificity of 88%. Conclusion-This PCR based test-holds promise of being an effective method of diagnosing Fusarium keratitis as web as Fusari um infections at other sites.