Project description:Little is known about the extent of genetic variability among Entamoeba strains and potential genotypic associations with virulence. Variable phenotypes have been identified for Entamoeba strains. E. histolytica is invasive and causes colitis and liver abscesses, but only in 10% of infected individuals; 90% of subjects remain asymptomatically colonized. E. dispar, a closely related species, appears to be incapable of causing invasive disease. In order to determine the extent of genetic diversity among Entamoeba strains we have developed an E. histolytica genomic DNA microarray and used it to genotype strains of E. dispar and E. histolytica. Based on the identification of divergent genetic loci, all six strains (four EH and two ED) had unique genetic fingerprints. Genomic regions with unusually high levels of divergence were identified indicating that structural or evolutionary pressures are molding selective regions of the Entamoeba genome. Comparison of divergent genetic regions allowed us to readily distinguish between EH and ED, identify novel genetic regions that may be used for strain and species typing, and identity a number of novel potential virulence determinants. Among these are Androgen Inducible Gene1, a CXXC receptor kinase, a peroxiredoxin 1-related gene, a Ras family member gene, a Rab geranylgeranyltransferase, and a gene with a UPF0034 domain. Among the four EH strains, an avirulent strain EH (Rahman) was the most divergent and phylogenetically distinct raising the intriguing possibility that genetic subtypes of E. histolytica may be at least partially responsible for the observed variability in clinical outcomes. Our approach shows the utility of a microarray-based genotyping assay to identify genetic variability between Entamoeba isolates and can readily be applied to the study of clinical isolates. A genotyping experiment design type classifies an individual or group of individuals on the basis of alleles, haplotypes, SNP's. Keywords: genotyping_design

Project description:BackgroundAmebiasis is a protozoal infection caused by Entamoeba histolytica, while the morphologically indistinguishable E. dispar is considered as non-pathogenic. Polymerase chain reaction (PCR) assays are necessary to differentiate both species. The most common clinical presentations of E. histolytica disease are amebic colitis and amebic liver abscess, but asymptomatic infection is also possible. We assessed the frequency and pattern of clinical symptoms and microscopic features in travelers/migrants associated with E. histolytica intestinal infection and compared them to those found in individuals with E. dispar infection.MethodsWe conducted a retrospective study at the travel clinic of the Institute of Tropical Medicine, Antwerp, Belgium on travelers/migrants found from 2006 to 2016 positive for Entamoeba histolytica/dispar through antigen detection and/or through microscopy confirmed by PCR. All files of individuals with a positive PCR for E. histolytica (= cases) and a random selection of an equal number of Entamoeba dispar carriers (= controls) were reviewed. We calculated the sensitivity, specificity and likelihood ratios (LRs) of clinical symptoms (blood in stool, mucus in stool, watery diarrhea, abdominal cramps, fever or any of these 5 symptoms) and of microscopic features (presence of trophozoites in direct and in sodium acetate-acetic acid-formalin (SAF)-fixed stool smears) to discriminate between E. histolytica and E. dispar infection.ResultsOf all stool samples positive for Entamoeba histolytica/dispar for which PCR was performed (n = 810), 30 (3.7%) were true E. histolytica infections, of which 39% were asymptomatic. Sensitivity, specificity and positive LRs were 30%, 100% and 300 (p 0.007) for presence of blood in stool; 22%, 100% and 222 (p 0.03) for mucus in stool; 44%, 90% and 4.7 (p 0.009) for cramps and 14%, 97% and 4.8 (p = 0.02) for trophozoites in direct smears. For watery diarrhea, fever and for trophozoites in SAF fixated smears results were non-significant.ConclusionsE. histolytica infection was demonstrated in a small proportion of travelers/migrants with evidence of Entamoeba histolytica/dispar infection. In this group, history of blood and mucus in stool and cramps had good to strong confirming power (LR+) for actual E. histolytica infection. Trophozoites were also predictive for true E. histolytica infection but in direct smears only.

Project description:Little is known about the extent of genetic variability among Entamoeba strains and potential genotypic associations with virulence. Variable phenotypes have been identified for Entamoeba strains. E. histolytica is invasive and causes colitis and liver abscesses, but only in 10% of infected individuals; 90% of subjects remain asymptomatically colonized. E. dispar, a closely related species, appears to be incapable of causing invasive disease. In order to determine the extent of genetic diversity among Entamoeba strains we have developed an E. histolytica genomic DNA microarray and used it to genotype strains of E. dispar and E. histolytica. Based on the identification of divergent genetic loci, all six strains (four EH and two ED) had unique genetic fingerprints. Genomic regions with unusually high levels of divergence were identified indicating that structural or evolutionary pressures are molding selective regions of the Entamoeba genome. Comparison of divergent genetic regions allowed us to readily distinguish between EH and ED, identify novel genetic regions that may be used for strain and species typing, and identity a number of novel potential virulence determinants. Among these are Androgen Inducible Gene1, a CXXC receptor kinase, a peroxiredoxin 1-related gene, a Ras family member gene, a Rab geranylgeranyltransferase, and a gene with a UPF0034 domain. Among the four EH strains, an avirulent strain EH (Rahman) was the most divergent and phylogenetically distinct raising the intriguing possibility that genetic subtypes of E. histolytica may be at least partially responsible for the observed variability in clinical outcomes. Our approach shows the utility of a microarray-based genotyping assay to identify genetic variability between Entamoeba isolates and can readily be applied to the study of clinical isolates. A genotyping experiment design type classifies an individual or group of individuals on the basis of alleles, haplotypes, SNP's. User Defined

Dataset Information

Different clinical outcomes of Entamoeba histolytica in Malaysia: does genetic diversity exist?

Publications

Different clinical outcomes of Entamoeba histolytica in Malaysia: does genetic diversity exist?

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets