DeterminaÃÃo da PrevalÃncia e Variabilidade GenÃtica de Entamoeba histolytica e Entamoeba dispar em Habitantes de Pernambuco

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

Previous studies using methods varying from traditional serological test to molecular biology have shown that in Northeast Brazil Entamoeba dispar was more prevalent than Entamoeba histolytica. In this work the prevalence was established by using E. histolytica stool antigen detection kits and Reaction Chain Polimerase (PCR) of genomic DNA extracted from cultured trophozoite in all four nuclei amoeba positive samples from individuals living in Northeast Brazil: Macaparana (1,437 samples); 3-14 years old school children from a Recife slum community (346 samples) and immunocompromised individuals attending the Hospital das ClÃnicas of the Universidade Federal de Pernambuco (109 samples). Among theses samples 104 were positive for the presence of tetranuclei ameba in those from Macaparana and Recife, respectively, whereas no one was found among from the immunocompromised individuals. However, all of these samples were negative towards the immunoenzymatic assay for the presence of E. histolytica-specific galactose adhesin. Out of the 103 tetranuclei ameba positive cultivated samples, only 52 showed trophozoites. DNA extraction of these samples, followed by PCR, showed that 42 samples were positive to E. dispar and no amplification was observed to the pathogenic E. histolytica. The remaining 10 samples were negative for both species. These findings are in accordance to previous studies performed in our laboratory based on gel diffusion precipitin, ELISA using E. histolytica trophozoite HM-1 IMSS antigen and Zymodemes. Furthermore, the genetic variability of Entamoeba dispar strains obtained from this survey (1783 samples) was investigated using two polymorphic speciesspecific loci (locus 1-2 and locus 5-6) with primers Dsp1/Dsp2 and Dsp5/Dsp6. A combinatory clustering analysis revealed no geographical correlation and a remarkable genetic polymorphism among 39 isolates examined. Nevertheless, a comparison of the frequency of 8 alleles, shared by both populations for the loci, showed that only one allele of locus 5-6 was highly significantly different between the two cities. These results suggested that Macaparana population is infected by similar strains and that locus 5-6 showed potential in assaying questions related to the molecular epidemiology of this region

ASSUNTO(S)

ciencias biologicas elisa elisa entamoeba dispar entamoeba histolytica entamoeba dispar entamoeba histolytica pcr genetic characterization caracterizaÃÃo genÃtica pcr

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