[Polymerase chain reaction versus conventional laboratory methods in the diagnosis of fungal keratitis]

ABSTRACT

To compare the value of conventional laboratory methods and polymerase chain reaction [PCR] in the diagnosis of fungal keratitis. This cross sectional study was conducted at Khalili Hospital, Shiraz, Iran. Samples were taken from thirty-eight patients with findings suspicious for fungal keratitis. Corneal scrapings were used for Gram, Giemsa and KOH stains, culture and PCR analysis. Of 38 enrolled eyes, 25 eyes [68.5%] were judged to have fungal infection based on positive cultures, staining, PCR or response to antifungal treatment. PCR detected fungi DNA in 17 of 25 samples [68% sensitivity]. Staining [Gram, Giemsa and KOH] and culture yielded a positive result in 40% and 24% of samples respectively. Twenty one [84%] of 25 patients showed fungal elements in at least one laboratory work up and 4 patients were diagnosed as fungal keratitis only based on response to antifungal drugs. Compared to conventional laboratory methods, PCR based methods offer higher sensitivity and a faster diagnosis in fungal keratitis