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

Autor(es)

A.C.M. Santos ^[1] ; A.C.M. Zidko ^[2] ; A.C. Pignatari ^[3] ; R.M. Silva ^[4]

Afiliação do(s) autor(es)

^[1] Universidade Federal de São Paulo. Imunologia e Parasitologia. Departamento de Microbiologia - Brasil

^[2] Universidade Federal de São Paulo. Imunologia e Parasitologia. Departamento de Microbiologia - Brasil

^[3] Universidade Federal de São Paulo. Departamento de Medicina. Laboratório Especial de Microbiologia Clínica - Brasil

^[4] Universidade Federal de São Paulo. Imunologia e Parasitologia. Departamento de Microbiologia - Brasil

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Medical and Biological Research; v. 46, n. 11, p. 968-973, 2013-10-15.

Resumo

Most of the knowledge of the virulence determinants of extraintestinal pathogenicEscherichia 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 extraintestinalE. 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. (AU)

• Processo FAPESP: 09/00402-6 - Estudo temporal da variabilidade de fatores de virulência e grupos filogenéticos de amostras de Escherichia coli patogênica extra-intestinal (ExPEC) isoladas de bacteremia em um hospital de São Paulo: sua relação com a evolução de ExPEC
• Beneficiário: Rosa Maria Silva
• Modalidade de apoio: Auxílio à Pesquisa - Regular