Résumé
In an effort to characterize, on the molecular scale, the Acanthamoeba initially isolated from the cornea of an amoebic keratitis patient associated with overnight-wear orthokeratology lens in Korea, we conducted mitochondrial DNA restriction fragment length polymorphism, 18S rDNA sequencing, and drug sensitivity analyses on the isolate (KA/PE1). The patient was treated with polyhexamethylene biguanide, chlorhexidine and oral itraconazole, which resulted in resolution of the patient's ocular inflammation. The majority of the molecular characteristics of the KA/PE1 were determined to be identical, or quite similar, to those of A. castellanii Ma strain, which had been isolated also from amoebic keratitis. The risk of Acanthamoeba keratitis as a potential complication of overnight orthokeratology is briefly discussed.
Sujets)
Humains , Femelle , Animaux , Adolescent , Analyse de séquence d'ADN , ARN ribosomique 18S/génétique , Polymorphisme de restriction , Tests de sensibilité parasitaire , Myopie/thérapie , Itraconazole/administration et posologie , Désinfectants/administration et posologie , ADN ribosomique/analyse , ADN des protozoaires/analyse , ADN mitochondrial/analyse , Lentilles de contact/effets indésirables , Chlorhexidine/administration et posologie , Biguanides/administration et posologie , Astigmatisme/thérapie , Antiprotozoaires/administration et posologie , Kératite à Acanthamoeba/traitement médicamenteux , Acanthamoeba/classificationRésumé
The taxonomy of Acanthamoeba spp., an amphizoic amoeba which causes granulomatous amoebic encephalitis and chronic amoebic keratitis, has been revised many times. The taxonomic validity of some species has yet to be assessed. In this paper, we analyzed the morphological characteristics, nuclear 18s rDNA and mitochondrial 16s rDNA sequences and the Mt DNA RFLP of the type strains of four Acanthamoeba species, which had been previously designated as A. divionensis, A. parasidionensis, A. mauritaniensis, and A. rhysodes. The four isolates revealed characteristic group II morphology. They exhibited 18S rDNA sequence differences of 0.2-1.1% with each other, but more than 2% difference from the other compared reference strains. Four isolates formed a different clade from that of A. castellanii Castellani and the other strains in morphological group II on the phylogenetic tree. In light of these results, A. paradivionensis, A. divionensis, and A. mauritaniensis should be regarded as synonyms for A. rhysodes.