Isoenzyme profile as parameter to differentiate pathogenic strains of Entamoeba histolytica in Brazil

Abstract

The isoenzyme profiles (IP) of 33 strains of Entamoeba histolytica isolated from patients and carriers of two regions in Brazil (Amazonia and Southeast) were determined. The enzymes phosphoglucomutase, glucose-phosphate isomerase, hexokinase and malic enzyme were considered. IP of the strains was correlated with culture conditions, time of maintenance in laboratory and clinical history of patients. The strains were maintained under polyxenic, monoxenic and axenic culture conditions: 27 polyxenic, 1 polyxenic and monoxenic, 1 polyxenic, monoxenic and axenic and 4 axenic only. The patients were symptomatic and asymptomatic. The symptomatic patients presented either non dysenteric (NDC) or dysenteric colitis (DC), associated or not with hepatic abscess (HA). One patient presented anal amoeboma (AM). The analysis of IP for isolates maintained in polyxenic culture showed non pathogenic IP (I) for strains from carriers and patients with NDC, while the strains isolated from patients presenting DC, HA and AM resulted in isolates II or XIX pathogenic IP. This parameter was not able to differentiate strains from carriers from symptomatic patients when these strains were found in axenic or monoxenic culture. All these strains displayed pathogenic IP (II), demonstrating the inability of this parameter to classifying for virulence since it showed identical IP for strains isolated from carriers or symptomatic patients.

Morphometric study of the hepatic lesions experimentally induced in hamsters byEntamoeba disparandE. histolytica

“…EGG strain was isolated from a patient with dysenteric colitis, hepatic abscess and positive serology. These samples were identified as E. dispar and E. histolytica by zymodeme and PCR (Martinez et al, 1996;Gomes et al, 1999). Trophozoites from each strain were thawed in water bath and maintained in Pavlova medium at 37 o C, with passages at each every three days.…”

Entamoeba dispar: Could it be pathogenic

“…Our group was the first to identify E. dispar isolated from symptomatic cases. [ 41 42 ] The strains isolated in these cases were also able to infect experimental animals. As noted earlier, the first experimental studies involving NP E. histolytica ( E. dispar ) did not succeed in reproducing the amebic lesions.…”

Influence of inflammation on parasitism and area of experimental amoebic liver abscess: an immunohistochemical and morphometric study

“…All procedures were conducted according to principles established by the Ethics Committee on Animal Experimentation of the UFMG. Ten Swiss mice were intra-hepatically inoculated with 250,000 trophozoites of the EGG strain of E. histolytica or MCR strain of E. dispar , previously identified by zymodeme and PCR [ 7 , 8 ]. Half of the animals were previously treated with two doses (0.5 mg/Kg) of dexamethasone, subcutaneously, 24 and 01 h before inoculation (Groups EGG-DEX and MCR-DEX) and, the other half received only buffered saline (Groups EGG and MCR).…”