Assessing the diversity of the virulence potential of Escherichia coli isolated from bacteremia in São Paulo, Brazil

Assessing the diversity of the virulence potential of Escherichia coli isolated from bacteremia in São Paulo, Brazil

Author Santos, A.c.m. Google Scholar
Zidko, A.c.m. Google Scholar
Pignatari, Antonio Carlos Campos Autor UNIFESP Google Scholar
Silva, Rosa Maria Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Abstract Most of the knowledge of the virulence determinants of extraintestinal pathogenic Escherichia coli (ExPEC) comes from studies with human strains causing urinary tract infections and neonatal meningitis and animal strains causing avian colibacillosis. In this research, we analyzed the phylogenetic background, the presence of 20 ExPEC virulence factors, and the intrinsic virulence potential of 74 E. coli strains isolated in São Paulo, Brazil, from 74 hospitalized patients (43 males and 31 females) with unknown-source bacteremia. Unlike other places in the world, the bacteremic strains originated equally from phylogroups B2 (35%) and D (30%). A great variability in the profiles of virulence factors was noted in this survey. Nevertheless, 61% of the strains were classified as ExPEC, meaning that they possessed intrinsic virulent potential. Accordingly, these strains presented high virulence factor scores (average of 8.7), and were positively associated with 12 of 17 virulence factors detected. On the contrary, the non-ExPEC strains, isolated from 39% of the patients, presented a generally low virulence capacity (medium virulence factor score of 3.1), and were positively associated with only the colicin cvaC gene. These results show the importance of discriminating E. coli isolates that possess characteristics of true pathogens from those that may be merely opportunistic in order to better understand the virulence mechanisms involved in extraintestinal E. coli infections. Such knowledge is essential for epidemiological purposes as well as for development of control measures aimed to minimize the incidence of these life-threatening and costly infections.
Keywords Bacteremia
Extraintestinal pathogenic Escherichia coli
Virulence factors
Intrinsic virulence potential
Phylogenetic background
Language English
Date 2013-11-01
Published in Brazilian Journal of Medical and Biological Research. Associação Brasileira de Divulgação Científica, v. 46, n. 11, p. 968-973, 2013.
ISSN 0100-879X (Sherpa/Romeo)
Publisher Associação Brasileira de Divulgação Científica
Extent 968-973
Access rights Open access Open Access
Type Article
SciELO ID S0100-879X2013001100968 (statistics in SciELO)

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