RESUMO
Enteropathogenic Escherichia coli (EPEC) that are known to cause severe diarrhoea in children and young rabbits are well characterized, but there are few reports on the serotypes and intimin (eae) types of EPEC in weaned pigs. Based on detection of the eae gene by PCR and by DNA-hybridisation with LEE specific gene probes, 20 intestinal and 17 faecal eae(+) strains from diarrhoeal (164) and non-diarrhoeal (57) weaned pigs from 13 Hungarian farms, representing 12.8% of diarrhoeal and 14.0% of non-diarrhoeal pigs, were identified. The dominant serotype was O123:H11 (40%) among intestinal, and O108:H9 (23%) among faecal strains. The majority (85%) of the intestinal strains possessed eae-beta and 10% carried eae-gamma gene. In contrast, significantly (p<0.025) fewer faecal strains (53%) harboured the eae-beta gene, and 23% were eae-gamma positive. In vitro adhesion tests of intestinal and faecal eae(+) strains indicated adhesion of 20/37 of the strains to PK15 (porcine kidney) cells while only 3/37 strains adhered to HeLa cells. The ultrastructure of intimate bacterial attachment of representative porcine eae(+) strains to PK15 cells showed no pedestal formation, in contrast to the human EPEC (O127:H5, eae-alpha) strain. In conclusion, the data do not demonstrate a significant role for the eae(+)E. coli in porcine post-weaning diarrhoea, but provide new information on a dominant porcine serotype (O123:H11, eae-beta), and on differences of serotypes and intimin types of porcine eae(+) strains according to their site of isolation. Furthermore there was an indication that the PK15 cell line could be used as a model to study in vitro adherence of eae(+)E. coli of some human and porcine origin.
Assuntos
Adesinas Bacterianas/genética , Diarreia/veterinária , Infecções por Escherichia coli/veterinária , Proteínas de Escherichia coli/genética , Escherichia coli/classificação , Doenças dos Suínos/microbiologia , Adesinas Bacterianas/classificação , Animais , Aderência Bacteriana , Estudos de Casos e Controles , Linhagem Celular , Primers do DNA/química , Diarreia/microbiologia , Escherichia coli/genética , Escherichia coli/patogenicidade , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/classificação , Fezes/microbiologia , Genótipo , Células HeLa , Humanos , Intestinos/microbiologia , Reação em Cadeia da Polimerase/métodos , Prevalência , Sorotipagem/métodos , Sorotipagem/veterinária , Suínos , Doenças dos Suínos/epidemiologia , DesmameRESUMO
PCR tests designed in these studies identified three rabbit adhesive factor genes among 43 enteropathogenic E. coli (EPEC) strains: afr1 (2 strains), the F4(K88)/CS31A-related afr2 (10 strains), and ral (15 strains). Several EPEC strains (i.e., O153:H7 and O157:H2) lacked these genes but did adhere to HeLa cells and produced attaching and effacing lesions in rabbits.
