Metabolism of phenylpropionic acid in enteropathogenic Escherichia coli belonging to serogroup O111 and its application for diagnosis.
We evaluated a biochemical assay based on the ability to metabolise beta-phenylpropionic acid (PPA) as a diagnostic aid in the identification of typical enteropathogenic Escherichia coli (EPEC) strains. A total of 1061 E. coli strains of serogroups O55, O111, and O119 were initially characterised regarding their H types (serotypes) and the presence of EPEC DNA sequences, eae, EAF, and bfpA. In case of the serogroup O111 strains, 84.6% carried the typical EPEC markers, and the great majority of those (98.1%) were PPA-positive. In contrast, only 0.9% of the serogroups O55 and O119 strains carrying the typical EPEC markers (53.6% and 75.4%, respectively) were PPA-positive. We conclude that the PPA test is a useful method to detect typical EPEC strains only among strains of the O111 serogroup.
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Seção de Bacteriologia, Institute Adolpho Lutz, Av Dr Arnaldo, 351, CEP 01246-902, São Paulo, Brazil. ikinue@hotmail.com
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D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques / Q000379:methods; D002648:Child; D002675:Child, Preschool; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D010666:Phenylpropionates / Q000378:metabolism*; D012703:Serotyping; D014774:Virulence / Q000235:genetics
D001426:Bacterial Proteins; D010666:Phenylpropionates; C035253:3-phenylpropionic acid