Genotyping of Acanthamoeba isolates and clinical characteristicsof patients with Acanthamoeba keratitis in China

Abstract

Acanthamoeba keratitis (AK) is a sight-threatening cornealinfection, the epidemiology of which is related to the specific genotype of Acanthamoeba. In this study, the genotypes of 14 Acanthamoebaisolates, each from a patient with AK, were identified according to the highlyvariable DF3 region in the 18S rRNA gene at Shandong Eye Institute, PR China,from 2000 to 2009, and the clinical characteristics of these patients wereanalysed. All 14 amoebae were genotype T4, representing nine different DF3sequence types, seven of which were newly identified. Cornea infestation wasthe main risk factor for these 14 AK patients. Amoebic cysts could be detectedin all corneal scrapes. Corneal ulcers were located mainly at the cornealcentre, accompanied by eye pain, and some appeared with a Wessely ring. Surgerywas carried out on all patients. Acanthamoeba genotypes T4/26and T4/27 were found to cause a more severe keratitis, whilst the othersshowed no significant differences in clinical characteristics. In conclusion,the majority of the keratitis-causing Acanthamoeba isolates weregenotype T4, with Acanthamoeba genotypes T4/26 and T4/27from PR China causing a more severe keratitis.