Detecção e caracterização de patotipos diarreiogênicos de Escherichia coli por métodos fenotípicos e genotípicos em indivíduos de todas as idades atendidos nas unidades de saúde de Vitória-ES

• Autor(a) principal: Cunha, keyla Fonseca da
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/1339
• topic: Doenças Infecciosas e Parasitárias; Escherichia coli; Reação em cadeia de polimerase; Gastroenterite; 61

Diarrhea is the second leading cause of mortality in <5 years and is responsible for decreased productivity in the economically active population. Among the infectious agents involved six diarrheagenics pathotypes of Escherichia coli (DEC) are worth mentioning: enteropathogenic E. coli (EPEC), enteroinvasive E. coli (EIEC), enterotoxigenic E. coli (ETEC), enterohemorragic E. coli or Shiga toxin-producing (EHEC/STEC), enteroaggregative E. coli (EAEC) and diffuselly adherent E. coli (DAEC). The aim of this study was to determine the frequency of DEC and to characterize phenotypic and genotypically EAEC, DAEC, aEPEC and chain-like adhesion E. coli (CLA) isolated from feces of all ages individuals treated at health units in the city of Vitória, between January 2008 and June 2011. E. coli were subjected to: (i) PCR for detection of eaeA, bfpA, aat, lt, st, ipaH, stx1 and stx2 genes; (ii) colony hybridization with eae, aat and daac probes; (iii) HEp-2 cells culture to show aggregative adherence (AA), diffuse (DA) and chain-like adhesion (CLA). PCR for detection of virulence genes was carried out in EAEC, CLA, DAEC and aEPEC. CLA and EAEC isolates were tested for biofilm formation and clump test. Fecal specimens (n=328) were obtained and E. coli was isolated from 85.7%. The following pathotypes were identified: EAEC (18.3%), DAEC (11%), aEPEC (2.6%), ETEC (0.7%). CLA was identified in 4.9% and EIEC, STEC and tEPEC were not detected. Out of the 60 isolates of EAEC (AA) (25% aat+ by PCR and 35% by hybridization) the aggregative adherence fimbriae were observed at low frequency (aggA-1.7%, aafA-0%, agg3A-11.7%, hda-8.3%). Typical EAEC were 31.7% of the EAEC isolates (aggR+), and among these, biofilm formation, score 3+ in clump test and the presence of aat, agg3A, hda, aap, sat, pet, iucA and set1A were significant. CLA isolates (87.5%) possessed the pet gene, all were aggR- and were clump test+, and no one was biofilm forming. Among the 42 isolates of DAEC (DA), the probe detected DAAC 52.4%. PCR showed adhesin afa/Dr (daad+/afa+) in 59.5% and AIDA-I adhesin was not found, suggesting that other adhesins are involved in DAEC adhesion. afa/Dr DAEC isolates were significant among <5 years. In aEPEC, the genes of pathogenicity island OI-122 (nleE, efa1/lifA and paa) and were seen in 30% all from <5 years. Virulence characteristics of tEAEC and DAEC Afa/Dr suggest that subpopulations are related diarrhea. CLA does not appear to be a EAEC variant.