Sensitive and rapid polymerase chain reaction based diagnosis of mycotic keratitis through single stranded conformation polymorphism.

PURPOSE: To report a method for early and correct diagnosis of mycotic keratitis.

DESIGN

Clinical laboratory diagnostic study.

METHODS

Corneal scraping of all the four patients were processed for DNA extraction which were amplified by fungal specific primers of internal transcribed spacer region I (ITS1). These products were sequenced and analyzed by single stranded conformation polymorphism (SSCP) for species identification.

RESULTS

The DNA samples from corneal scrapings of all the four patients were successfully amplified by the primer pair ITS1 and ITS2 and similarity/dissimilarity were established by Jaccard's coefficient. Patient isolate 1 was identified as Nectria hematococca, isolate 2 as Candida albicans, and isolates 3 and 4 were identified as Bipolaris papendorfii. This led to prompt initiation of antifungal therapy in all the four cases where useful vision could be restored.

CONCLUSIONS

Early and correct diagnosis of mycotic keratitis by polymerase chain reaction could be obtained in all the four cases compared with conventional methods, which helped in the prompt initiation of antifungal therapy in patients.