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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Occurrence of virulence-related sequences and phylogenetic analysis of commensal and pathogenic avian Escherichia coli strains (APEC)

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Author(s):
de Campos, Tatiana Amabile [1] ; Lago, Juliana Carvalhaes [1] ; Nakazato, Gerson [1] ; Stehling, Eliana Guedes [1] ; Brocchi, Marcelo [1] ; Pestana de Castro, Antonio Fernando [2] ; da Silveira, Wanderley Dias [1]
Total Authors: 7
Affiliation:
[1] Univ Estadual Campinas, Depto Microbiol & Imunol, Inst Biol, BR-13081862 Campinas, SP - Brazil
[2] Univ Sao Paulo, Dept Microbiol, Inst Ciencias Biomed 2, BR-05505900 Sao Paulo - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Pesquisa Veterinária Brasileira; v. 28, n. 10, p. 533-540, OCT 2008.
Web of Science Citations: 6
Abstract

The presence of iron uptake (irp-2, fyuA, sitA, fepC, iucA), adhesion (iha, lpfA(O157/O141), lpfA(O157/O154), eta, toxB) and invasion (inv, ial-related DNA sequences and assignment to the four main Escherichia coli phylogenetic groups (A, B1, B2 e D) were determined in 30 commensal E coli strains isolated from healthy chickens and in 49 APEC strains isolated from chickens presenting clinical signs of septicemia (n=24) swollen head syndrome (n=14) and omphalitis (n=11) by PCR. None of the strains presented DNA sequences related to the inv, ial, efa, and toxB genes. DNA sequences related to lpfA(O157/O154), iucA, fepC, and irp-2 genes were significantly found among pathogenic strains, where iucA gene was associated with septicemia and swollen head syndrome and fepC and irp-2 genes were associated with swollen head syndrome strains. Phylogenetic typing showed that commensal and omphalitis strains belonged mainly to phylogenetic Group A and swollen head syndrome to phylogenetic Group D. Septicemic strains were assigned in phylogenetic Groups A and D. These data could suggest that clonal lineage of septicemic APEC strains have a multiple ancestor origin; one from a pathogenic bacteria ancestor and other from a non-pathogenic ancestor that evolved by the acquisition of virulence related sequences through horizontal gene transfer. Swollen head syndrome may constitute a pathogenic clonal group. By the other side, omphalitis strains probably constitute a non-pathogenic clonal group, and could cause omphalitis as an opportunistic infection. The sharing of virulence related sequences by human pathogenic E coli and APEC strains could indicate that APEC strains could be a source of virulence genes to human strains and could represent a zoonotic risk. (AU)