Value of microscopy in the diagnosis of dysentery associated with invasive Entamoeba histolytica.

Abstract

Aims-To assess the reliability of the detection of erythrophagocytic amoebic trophozoites in stool samples in the diagnosis of dysentery associated with invasive Entamoeba histolytica. Methods--Amoebic culture was carried out on single stool samples collected from patients from Mexico, Colombia, and Bangladesh. The stools had been examined by light microscopy. Amoebic dysentery was diagnosed when erythrophagocytic E histolytica trophozoites were observed in a case of bloody diarrhoea. E histolytica isolates were characterised by isoenzyme electrophoresis and results correlated with microscopical findings in stools. Statistical analysis was performed using the x2 test. Results-Where erythrophagocytic amoebae had been observed in dysenteric stool specimens the E histolytica phenotype was invariably invasive (p < 0*0001). Observation of erythrophagocytic amoebae in dysentery is 100% specific and predictive of infection with invasive E histolytica. When amoebic culturepositive cases only are considered it is 96% sensitive. In this study E histolytica of zymodeme XIV was more commonly associated with amoebic dysentery than zymodeme II. There was no significant difference between the carriage rate of invasive and non-invasive E histolytica in non-dysenteric diarrhoea. Asymptomatic subjects carried non-invasive E histolytica more frequently than invasive E histolytica. Patients with non-amoebic dysentery, when shown to be infected with E histolytica, carried non-invasive strains (12%

Differentiation of entamoeba histolytica/entamoeba dispar by PCR and their correlation with humoral and cellular immunity in individuals with clinical variants of amoebiasis.

“…The cohort of AIA comprised the cases of apparent amoebic dysentery referred from a suburban clinic over a 2-year period. The parasitological diagnosis consisted on the finding of trophozoites associated with the presence of mucus and /or blood, a widely used method effective in the diagnosis of AIA, 44 in accordance with recommendations of the World Health Organization (1997).…”

Development of Multiplex Real-Time Polymerase Chain Reaction for Detection of Entamoeba histolytica, Entamoeba dispar, and Entamoeba moshkovskii in Clinical Specimens

“…1 This procedure is cheap and simple, but it has several limitations, such as being incapable of distinguishing between the cysts and trophozoites of the disease-causing species Entamoeba histolytica , the nonpathogenic Entamoeba dispar , and the free-living amoeba Entamoeba moshkovskii . A high prevalence and association of E. moshkovskii with E. histolytica and E. dispar has been reported in young children from Bangladesh 2,3 and E. moshkovskii was recently detected in patients between 31 and 50 years of age presenting with gastrointestinal symptoms in Australia 4 ; therefore, humans may be a true host for this amoeba.…”

Comparison of multiplex-PCR and antigen detection for differential diagnosis of Entamoeba histolytica

“…However, it reaches about 60% sensitivity and can give false-positives due to misidentification of non-pathogenic Entamoeba species [15][16][17][18]. The examination of fecal samples by optic microscope is not able to identify or differentiate E. histolytica from E. dispar unless erythrophagocytosis (the presence of ingested RBCs in trophozoites) is seen during microscopic examination [11,19].…”