Evaluation of polymerase chain reaction-based ribosomal DNA Sequencing technique for the diagnosis of mycotic keratitis

PURPOSE: To evaluate the polymerase chain reaction (PCR) and sequencing,based ribosomal deoxyribonucleic acid (rDNA) typing technique for rapid and sensitive diagnosis of fungal keratitis. DESIGN: Laboratory investigation. METHODS: The present study included culture-based methods along with PCR and ITS2/5.8S rDNA sequenc,ing to evaluate fungal infections in 32 corneal scrapings from patients with suspected mycotic keratitis. RESULTS: Good correlation was found between the culture and PCR rDNA sequencing-based methods. We also identified fungal strains that were noncultivable in routine culture medium and fungal strains, which have been reported scarcely in previous reports from eastern Indian studies. CONCLUSIONS: The PCR and rDNA sequencing, based approaches may be useful alternatives to culture, based techniques for the rapid and sensitive diagnosis of fungal keratitis. We found that clinically significant pathogenic fungal strains can be detected and differ, entiated by this method in a short period. This method therefore is useful for the early treatment of fungal infection.