Random amplified polymorphic DNA profiles as a tool for the characterization of Brazilian keratitis isolates of the genus Acanthamoeba

The genus Acanthamoeba comprises free-living amebae identified as opportuni stic pathogens of humans and other animal species. Morphological, biochemic al and molecular approaches have shown wide genetic diversity within the ge nus. In an attempt to determine the genetic relatedness among isolates of A canthamoeba we analyzed randomly amplified polymorphic DNA (RAPD) profiles of Il Brazilian isolates from cases of human keratitis and 8 American type culture collection (ATCC) reference strains. We found that ATCC strains bel onging to the same species present polymorphic RAPD profiles whereas strain s of different species show very similar profiles. Although most Brazilian isolates could not be assigned with certainty to any of the reference speci es, they could be clustered according to pattern similarities. The results show that RAPD analysis is a useful tool for the rapid characterization of new isolates and the assessment of genetic relatedness of Acanthamoeba spp. A comparison between RAPD analyses and morphological characteristics of cy st stages is also discussed.