PCR detects fungal DNA in keratitis

Polymerase chain reaction (PCR) could be used to diagnose fungal keratitis, claims an investigation in the journal Eye.

A team led by Dr N. Tananuvat, Department of Ophthalmology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand, conducted a prospective nonrandomized study on 30 eyes of 30 patients with presumed fungal keratitis.

Each patient underwent corneal scraping and fungal-specific primers were used to analyse the specimens. PCR products were cloned and sequenced and compared to conventional microbial work-up.

PCR demonstrated positivity in 93.3%, culture in 40% and potassium hydroxide in 20% of the total patients included in the study. Out of the 28 PCR-positive patients, 12 were culture-positive and 16 were culture-negative.

There were no false-negative results in the culture-positive specimens recorded by the PCR, suggesting it is able to accurately detect fungal DNA in a high percentage of culture-negative cases. The procedure could be helpful, in addition to smear and culture in the efficient diagnosis of fungal keratitis.

Please click here to read the abstract.