Korean J Parasitol.  2008 Sep;46(3):157-164. 10.3347/kjp.2008.46.3.157.

Keratitis by Acanthamoeba triangularis: Report of Cases and Characterization of Isolates

Affiliations
  • 1Department of Parasitology, Kyungpook National University School of Medicine, Daegu 700-422, Korea. dichung@knu.ac.kr
  • 2Apgujung St. Mary's Eye Center, Seoul, Korea.

Abstract

Three Acanthamoeba isolates (KA/E9, KA/E17, and KA/E23) from patients with keratitis were identified as Acanthamoeba triangularis by analysis of their molecular characteristics, a species not previously recognized to be a corneal pathogen. Epidemiologic significance of A. triangularis as a keratopathogen in Korea has been discussed. Morphologic features of Acanthamoeba cysts were examined under a microscope with differential interference contrast (DIC) optics. Mitochondrial DNA (mtDNA) of the ocular isolates KA/E9, KA/E17, and KA/E23 were digested with restriction enzymes, and the restriction patterns were compared with those of reference strains. Complete nuclear 18S and mitochondrial (mt) 16S rDNA sequences were subjected to phylogenetic analysis and species identification. mtDNA RFLP of 3 isolates showed very similar patterns to those of SH621, the type strain of A. triangularis. 16S and 18S rDNA sequence analysis confirmed 3 isolates to be A. triangularis. 18S rDNA sequence differences of the isolates were 1.3% to 1.6% and those of 16S rDNA, 0.4% to 0.9% from A. triangularis SH621. To the best of our knowledge, this is the first report, confirmed by 18S and 16S rDNA sequence analysis, of keratitis caused by A. triangularis of which the type strain was isolated from human feces. Six isolates of A. triangularis had been reported from contaminated contact lens cases in southeastern Korea.

Keyword

Acanthamoeba ; keratitis; contact lenses; Acanthamoeba triangularis

MeSH Terms

Acanthamoeba/classification/genetics/isolation & purification
Acanthamoeba Keratitis/*drug therapy/*parasitology
Adolescent
Adult
Animals
Antiprotozoal Agents/therapeutic use
Biguanides/therapeutic use
DNA, Mitochondrial/genetics
DNA, Protozoan/genetics
Female
Humans
Male
Phylogeny
Polymorphism, Restriction Fragment Length
RNA, Ribosomal, 16S/genetics
RNA, Ribosomal, 18S/genetics
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