Entamoeba Histolytica Research Articles

Prevalence of viral, bacterial and parasitic enteropathogens among young children with acute diarrhoea in Jeddah, Saudi Arabia.

The prevalence of viral, bacterial and parasitic pathogens among children of Jeddah, Saudi Arabia, was investigated. During December 1995-October 1996, 576 faecal samples were collected from children (0-5 year(s) old) suffering from acute diarrhoea and attending hospitals and outpatient clinics in Jeddah. One or more enteropathogen(s) were identified in 45.6% of the stool specimens. Mixed infections were detected in 12.2% of the diarrhoeal cases. Rotavirus was detected in 34.6% of the specimens of the hospitalized patients and in 5.9% of the specimens of the outpatients. Fifty-one percent of the rotavirus-positive specimens were long electropherotype, 26% were short electropherotype, and 23% could not be electropherotyped specifically. Among those of the long electropherotype, there were six patterns; and of the short electropherotypes, there were four patterns. Serotyping of these specimens revealed a distribution of 39.6%, 4.2%, 6.3%, and 15.6% for rotavirus serotype 1, 2, 3, and 4 respectively. Mixed serotypes were found in 3.1%, and 31.3% of the specimens were untypeable. Other aetiologic agents recognized included Escherichia coli (13%), of which 3.8% were enteropathogenic E. coli (EPEC) and 1.9% enterohaemorrhagic E. coli. Among the E. coli (EPEC) serotypes, O111:K58:B4, O55:K59:B11, and 0127:K63:B8 were found in 31.8%, 18.2%, and 13.6% of the cases respectively. Serotype 026:K60:B6, 0124:K72:B17, and 0112:K66:B11 each was found in 9.1% of the EPEC cases. 0128:K67:B12 and 0125:K70:B13 each was found in one case only. Other detected pathogens were: Klebsiella pneumoniae (4%), Giardia lamblia (3.1%), Salmonella sp. (3%), Shigella flexneri (2.6%), Entamoeba histolytica (2.2%), Trichuris trichiura, Hymenolepis nana, and Ascaris lumbricoides (0.7% each), and Candida albicans (0.5%). Based on the results of this study, it is concluded that the high prevalence of the various enteropathogens among young children is a significant public health problem.

Effect of Cyclosporine A on Entamoeba histolytica

Effect of Cyclosporine A on Entamoeba histolytica

Expression and Immunodetection of a P-Glycoprotein in Emetine-Resistant Trophozoites of Entamoeba histolytica

exico **Programa de Biomedicina Molecular, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada del I.P.N. (CICATA-IPN), Mexico City, Mexico

Identification of enteric pathogens in HIV-positive patients with diarrhoea in northern India.

Enteric pathogens associated with chronic diarrhoea in HIV-positive patients were studied. The study was conducted during January 1995-December 1998. Stool specimens from all diarrhoea patients (n = 26) were examined microscopically for ova and parasites using wet preparations and stained smears. Stool samples from diarrhoea patients were also cultured on appropriate media to isolate enteric bacterial pathogens. Of the 59 patients, 26 (44%) had prolonged diarrhoea for more than 4 weeks. Enteric pathogens were detected in 19 (73%) of the 26 patients: 17 patients harboured a single pathogen, and 2 patients had mixed pathogens. The detection rate of emerging parasites, including Isospora, Cryptosporidium, Blastocystis hominis, and Strongyloides stercoralis as a single agent, was significantly higher than conventional pathogens (50% vs 19.2%; p < 0.05). Only one patient harboured both conventional and emerging pathogens (Entamoeba histolytica and Cryptosporidium). Isospora belli was detected in 8 (31%) of the 26 diarrhoea patients: in 7 (27%) patients as a single agent and in one patient with S. stercoralis. Cryptosporidium was identified in 3 (11%) diarrhoea patients: in 2 (8%) patients as a single agent and in one patient with E. histolytica, followed by B. hominis in 2 (8%) patients. E. histolytica was most commonly isolated (3/26; 11.5%), followed by Giardia lamblia, enteropathogenic Escherichia coli, and Campylobacter jejuni (one patient each). Parasitic pathogens were frequently associated with HIV-positive patients with diarrhoea in northern India. I. belli was the most frequent parasite isolated, followed by Cryptosporidium. Stools of all HIV-positive patients with diarrhoea should thoroughly be investigated to identify aetiologic agents for proper management.

Prevelence of Entamoeba histolytica and Giardia lamblia in primary school pupils in five rural villages around Kaduna and Zaria, Nigeria

Prevelence of Entamoeba histolytica and Giardia lamblia in primary school pupils in five rural villages around Kaduna and Zaria, Nigeria

Detection by HPLC of a trypanothione synthetase activity in vitro from Entamoeba histolytica.

We have previously demonstrated the presence of glutathione-spermidine (Gsp) and trypanothione [T(SH)(2)] from Entamoeba histolytica trophozoites, on the basis of results obtained with acid extracts purified by Florisil and DEAE-cellulose, derivatized with the fluorescent reagent monobromobimane and separated by HPLC. Gsp was originally found in Escherichia coli and later in trypanosomatids such as Trypanosoma cruzi, T. brucei, T. congolense and the insect trypanosomatid Crithidia fasciculata, along with the novel compound T(SH)(2), N(1), N(8)-bis(glutathionyl)-spermidine. Here we demonstrate the presence of a T(SH)(2) synthetase activity in partly purified extracts from Entamoeba histolytica HK9, incubated at two pH values (6.5 and 7.5) with reduced glutathione (GSH), spermidine and ATP, in the presence of Mg(2+) at different time intervals. The thiol products were detected by HPLC in picomole amounts and compared with commercial Gsp and T(SH)(2) standards. We have used also an extract of Crithidia luciliae as a reference, to compare our results with C. fasciculata, in which the presence of this enzyme has previously been demonstrated and was later purified and separated into two synthetase activities from the same source: one for Gsp and the other for T(SH)(2). The presence of a T(SH)(2) synthetase activity in Entamoeba histolytica means that this protozoan has a similar metabolism to that of the trypanosomatids and opens the possibility of establishing a rational drug design against this human parasite.

Entamoeba histolytica: a eukaryote with trypanothione metabolism instead of glutathione metabolism.

Entamoeba histolytica is a human pathogen that lacks the capacity to synthesize glutathione but can incorporate it, from the growth media or presumably from the human host, to form trypanothione [N(1), N(8)-bis(glutathionyl)-spermidine conjugate]. This novel thiol compound has previously been found in trypanosomatids, as has its precursor glutathionyl-spermidine, which was originally detected in Escherichia coli. Previously we showed the presence of these two thiol compounds in extracts from cultures of Entamoeba histolytica HK9. Here we report that when Entamoeba histolytica HK9 is grown in a culture medium that lacks glutathione (treated with the enzyme gamma-glutamyl transpeptidase), trypanothione is not formed, although the trophozoites can continue dividing for at least 60 h but at 25% lower cell density. The finding of a trypanothione metabolism in Entamoeba histolytica raises many questions: one concerns the possibility of a phylogenetic relationship, in this respect, with trypanosomatids such as Trypanosoma cruzi, T. brucei and Crithidia fasciculata; another concerns its role in cell metabolism; a third concerns it possible use as a target for a rational drug design strategy against this parasite.

Analysis of cysteine biosynthetic pathway in entamoeba histolytica: involvement of cysteine in the antioxidative mechanism

Analysis of cysteine biosynthetic pathway in entamoeba histolytica: involvement of cysteine in the antioxidative mechanism

Evaluation of five different media for xenic cultivation of entamoeba histolytica.

Evaluation of five different media for xenic cultivation of entamoeba histolytica.

Zymodeme patterns of entamoeba histolytica strains isolated from clinical patients

Zymodeme patterns of entamoeba histolytica strains isolated from clinical patients

Distinguishing pathogenic entamoeba histolytica from nonpathogenic E. dispar

Distinguishing pathogenic entamoeba histolytica from nonpathogenic E. dispar

Samsun Bölgesinde Çocukluk Çağı İshallerinde Campylobacter Cinsi

The Role of Campylobacters as Causes of Childhood Diarrhoea in Samsun Region One hundred children aged one month to 14 years who were admitted with acute diarrhoea was studied to determine the relative frequency of Campylobacters as causes of childhood infectious diarrhoea. Demographic characteristics, the duration of symptoms, clinical manifestations and findings and nature of stools of all patients were noted. Stools were cultured for Escherichia coli, salmonellas, shigellas, and Campylobacters; they were examined microscopically for ova, cysts, or parasites, blood and leukocytes. Rotavirus antigen was also detected by latex agglutination test in stools. Since isolates of Escherichia coli were not typed they were not considered as agents. Rotavirus and protozoan pathogens [Entamoeba histolytica and Giardia lamblialis) were detected as most common causes of diarrhoea, respectively 12% and 11%. Campylobacters were most common bacteria isolated (8%). Salmonella was isolated from 5%, and shigella from 2% of patients. Isolation rates for all pathogens were 38%. This study suggested that Campylobacters were one of the major causes of childhood acute diarrhoea and stools of children with acute diarrhoea should cultured routinely for this pathogen. Cocukluk cagi enfeksiyoz ishallerinde Campylobacter cinsi bakterilerin etken olarak gorulme sikligini belirlemek amaciyla akut ishal yakinmasiyla basvuran ve yaslari 1 ay ile 14 yas arasinda degisen 100 cocuk calismaya alindi. Tum hastalarin demografik ozellikleri, semptomlari ve suresi, klinik bulgular ve diski ozellikleri kaydedildi. Diski mikroskopisinde eritrosit, lokosit ve parazit incelemesi yapildi. Diskilar salmonella, shigella ve Campylobacter izolasyonu icin uygun kultur ortamlarina ekildi. Aynca lateks aglutinasyon yontemi ile diskida rotavirus antijeni arastirildi. Olgularin %38'inde gastroenterit etkeni saptanabildi. En siklikla saptanan etkenler rotavirus (%12) ve protozoal etkenler [Entemoeba histolytica ve Giardia lamblialis) (%11) idi. Bakteriyel etkenler arasinda en fazla izole edilen mikroorganizma Campylobacter (%8) idi. Salmonella %5, shigella ise %2 oraninda izole edildi. Bu calisma cocukluk cagi akut ishallerinde Campylobacter cinsi bakterilerin onemli etkenlerden birisi oldugunu gostermistir. Sonuc olarak, akut ishal olgularinda etken saptanmasi amaciyla diski kulturu alma endikasyonu varsa Campylobacter besi yerine de ekim yapilmasi gerektigi kanisina varilmistir.

Differentiation of pathogenic Entamoeba histolytica and nonpathogenic Entamoeba dispar by PCR

Differentiation of pathogenic Entamoeba histolytica and nonpathogenic Entamoeba dispar by PCR

Recent advances in DNA-mediated gene transfer of entamoeba histolytica

During the past few years, the introduction of DNA-mediated gene transfer into parasite research has permitted subtle studies on fundamental aspects of parasite biology. In this paper, Egbert Tannich describes the recent breakthrough of successful Entamoeba histolytica transfection, and the subsequent developments in this field.

5459042 Procedure to preserve antigens of entamoeba histolytica without enzymatic inhibitors : Flores de Castaneda Maria D San Jemo, Monterrey, Mexico

5459042 Procedure to preserve antigens of entamoeba histolytica without enzymatic inhibitors : Flores de Castaneda Maria D San Jemo, Monterrey, Mexico

Prevalence of intestinal parasites in Saudi children: a community-based study.

A community-based study was undertaken to determine the prevalence and types of intestinal parasites in the pediatric population of Al-Baha region, Saudi Arabia. Stool samples were randomly collected from 19,939 children of whom 4208 (21.1%) were found to harbour intestinal parasites. The most affected age group was 5-9 years and the sex distribution was almost equal in all age groups. Specific prevalence rates were Giardia lamblia 9 per cent, entamoeba histolytica 5 per cent, Hymenolepis nana 2 per cent, and Enterobius vermicularis 2 per cent. The findings of this survey confirm the extremely complex nature of parasitic profile in developing communities, and indicate that relationships exist between cultural and ecological factors, sanitation, and observed pattern of intestinal parasites.

Adherence and cytotoxicity of Entamoeba histolytica or how lectins let parasites stick around

Adherence and cytotoxicity of Entamoeba histolytica or how lectins let parasites stick around

Pathogenicity, virulence and Entamoeba histolytica.

Pathogenicity, virulence and Entamoeba histolytica.

A simple and rapid technique for concentration ofentamoeba histolyticacysts from contaminated water

Entamoeba histolytica, the causative agent of amebiasis, has world wide distribution. A simple and rapid technique was developed for the concentration of Entamoeba histolytica cysts from contaminated water. The efficiency of the procedure is 80% and it requires five hours. The procedure was used to determine Entamoeba histolytica cysts in water samples from various sampling points on river Kanhan and the lakes in and around Nagpur City. The cyst recovery in environmental samples varied from 0.3 to 31 cysts/L. This methodology can prove useful for rapid detection of the cysts in contaminated water by microscopic or nucleic acid probe techniques.

Speciation and clonality in Entamoeba histolytica

Speciation and clonality in Entamoeba histolytica