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

Abstract

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 sequencing 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 differentiated by this method in a short period. This method therefore is useful for the early treatment of fungal infection.