Real-time PCR for laboratory diagnosis of Acanthamoeba keratitis

Abstract

Acanthamoeba keratitis is a painful vision-threatening disease of the human cornea. It is characterised by severe ocular pain or partial paracentral stromal ring infiltrate, which can be frequently misdiagnosed as herpes simplex virus keratitis. If the infection is not treated promptly, it may progress to ulceration of the cornea, loss of visual acuity, possibly blindness and even require enucleation. Acanthamoeba sp are found commonly in freshwater, tap water, seawater, hot springs and swimming pools. An epidemiologic case study revealed that major risk factors were the use of contact lenses, predominantly extended-wear soft lenses, the use of homemade rinsing saline and users who wear their lenses while swimming. The conventional method of detecting the formation of oocysts of Acanthamoeba by a culture technique takes an average three–five days. DNA amplification by PCR can improve turnaround time for the diagnosis. A study was carried out in this laboratory to compare the traditional culture method with a real-time PCR assay.