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BioMed Research International
Volume 2014, Article ID 465054, 9 pages
Research Article

Molecular Screening of Virulence Genes in Extraintestinal Pathogenic Escherichia coli Isolated from Human Blood Culture in Brazil

Laboratory of Basic and Applied Bacteriology, Department of Microbiology, Universidade Estadual de Londrina, Rodovia Celso Garcia Cid, 86051-980 Londrina, PR, Brazil

Received 27 November 2013; Revised 13 March 2014; Accepted 17 March 2014; Published 15 April 2014

Academic Editor: Ketoki Kapila

Copyright © 2014 Vanessa L. Koga et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Extraintestinal pathogenic Escherichia coli (ExPEC) is one of the main etiological agents of bloodstream infections caused by Gram-negative bacilli. In the present study, 20 E. coli isolates from human hemocultures were characterized to identify genetic features associated with virulence (pathogenicity islands markers, phylogenetic group, virulence genes, plasmid profiles, and conjugative plasmids) and these results were compared with commensal isolates. The most prevalent pathogenicity island, in strains from hemoculture, were PAI IV536, described by many researchers as a stable island in enterobacteria. Among virulence genes, iutA gene was found more frequently and this gene enconding the aerobactin siderophore receptor. According to the phylogenetic classification, group B2 was the most commonly found. Additionally, through plasmid analysis, 14 isolates showed plasmids and 3 of these were shown to be conjugative. Although in stool samples of healthy people the presence of commensal strains is common, human intestinal tract may serve as a reservoir for ExPEC.