title: Amoebic liver abscess production by Entamoeba dispar.
abstract: Although Entamoeba dispar displays a similar morphology to Entamoeba histolytica, cellular and molecular studies have revealed significant differences between these two amoebae, including the former being characterized as non-pathogenic and the later as pathogenic. However, recent  in vivo and  in vitro experiments  have  shown  that  E.  dispar  strains  of  different  origin  are  capable  of  causing  liver  damage  and destroying cell culture lines in the presence of common intestinal bacteria. These results suggested that E. dispar may present pathogenic behavior according to the specific E. dispar strain, culture and environmental conditions. To investigate this possibility, we carried out in vivo and in vitro studies using a xenic strain E. dispar (ICB-ADO) isolated from a symptomatic non-dysenteric Brazilian patient. This strain was able to induce liver necrosis in a hamster model that was more severe than that produced by E. histolytica. The ICB-ADO isolate also caused significantly more destruction of cultured MDCK cells and increased loss of transepithelial resistance than did the E. histolytica. Xenic E. dispar exhibited high proteolytic activity, which  was  partially  inhibited  by  the  addition  of  cysteine-protease  inhibitors.  Based  on  our  biochemical and molecular characterization of E. dispar (ICB-ADO) xenic culture and its ability to produce liver abscesses, we conclude that this specific strain can indeed produce tissue damage, distinct from the frequently used non- pathogenic E. dispar SAW 760 strain.
authors.affiliation: Department of Morphology, Laboratory of Parasitology, Federal University of Sergipe, Aracaju, Sergipe, Brazil.
authors.forename: Silvio S
authors.initials: SS
authors.lastname: Dolabella
authors.forename: Jesús
authors.initials: J
authors.lastname: Serrano-Luna
authors.forename: Fernando
authors.initials: F
authors.lastname: Navarro-García
authors.forename: René
authors.initials: R
authors.lastname: Cerritos
authors.forename: Cecilia
authors.initials: C
authors.lastname: Ximénez
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Galván-Moroyoqui
authors.forename: Edward F
authors.initials: EF
authors.lastname: Silva
authors.forename: Víctor
authors.initials: V
authors.lastname: Tsutsumi
authors.forename: Mineko
authors.initials: M
authors.lastname: Shibayama
mesh_terms: D000818:Animals; D001938:Brazil; D002478:Cells, Cultured; D006224:Cricetinae; D004195:Disease Models, Animal; D004285:Dogs; D004747:Entamoeba / Q000145:classification* / Q000472:pathogenicity*; D006801:Humans; D066298:In Vitro Techniques; D015994:Incidence; D007668:Kidney / Q000469:parasitology / Q000473:pathology; D008099:Liver / Q000469:parasitology* / Q000473:pathology; D008101:Liver Abscess, Amebic / Q000453:epidemiology / Q000469:parasitology* / Q000473:pathology; D008297:Male; D008647:Mesocricetus; D059748:Proteolysis