Detection of Acanthamoeba in tap water and contact lens cases using polymerase chain reaction

Purpose. To detect the presence of Acanthamoeba in Hong Kong tap water and the contamination of contact lens cases using a polymerase chain reaction (PCR) method. Methods. Tap water was collected from the bathroom sink of 100 households in Hong Kong and tested for the presence of Acanthamoeba by means of PCR amplification. Characteristics of homes were noted with respect to age, building type, and location. A sample of 100 contact lens cases were collected from regular users of contact lenses and tested for the presence of Acanthamoeba by PCR. Results. Ten percent of water samples were contaminated by Acanthamoeba. The risk for contamination was higher in older properties, those located in the urban area of Kowloon, and those in which the bathroom tap was served by a water tank. Only one contact lens case yielded Acanthamoeba. The subject admitted poor compliance with lens care routines. Conclusions. Levels of Acanthamoeba detected using PCR were somewhat higher than previously reported in Hong Kong. Older plumbing and poorly maintained water storage tanks may increase the risk of Acanthamoeba contamination. Poor compliance with care of the lens case, allowing for the build up of biofilm may increase the risk of Acanthamoeba contamination of the case and possible Acanthamoeba keratitis.