The Laredo strain and other 'Entamoeba histolytica-like' amoebae are Entamoeba moshkovskii

Abstract

A small number of Entamoeba isolates from humans, the best known of which is the 'Laredo' strain, have the ability to grow at room temperature. This peculiarity, along with other characteristics, distinguishes the strains from the human pathogen E. histolytica despite their being morphologically inseparable. In contrast, these 'E. histolytica-like' strains share several features with E. moshkovskii, which is most frequently isolated from polluted water. To examine the taxonomic relationships among these morphologically similar organisms, we have used polymerase chain reaction amplification of the small subunit ribosomal RNA gene combined with restriction fragment length polymorphism analysis, 'riboprinting'. The results clearly show that the 'E. histolytica-like' amoebae are indeed strains of E. moshkovskii, and not closely related to E. histolytica.