Showing papers by "Gerson Nakazato published in 2008"
TL;DR: The presence of iron uptake, adhesion, and invasion sequences and assignment to the four main Escherichia coli phylogenetic groups were determined in 30commensal E. coli strains isolated from healthy chickens and in 49 APEC strains isolatedfrom chickens presenting clinical signs of septicemia and omphalitis.
Abstract: The presence of iron uptake (irp-2, fyuA, sitA, fepC, iucA), adhesion (iha, lpfA O157/O141, lpfA O157/O154, efa, 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.
18 citations
TL;DR: It is demonstrated that fliC conserved regions may be associated with pathogenic clones of APEC strains, and also shows a great similarity among APEC and H-antigens of E. coli strains isolated from humans.
Abstract: The clonal relationship among avian Escherichia coli strains and their genetic proximity with human pathogenic E. coli, Salmonela enterica, Yersinia enterocolitica and Proteus mirabilis, was determined by the DNA sequencing of the conserved 5' and 3'regions fliC gene (flagellin encoded gene). Among 30 commensal avian E. coli strains and 49 pathogenic avian E. coli strains (APEC), 24 commensal and 39 APEC strains harbored fliC gene with fragments size varying from 670bp to 1,900bp. The comparative analysis of these regions allowed the construction of a dendrogram of similarity possessing two main clusters: one compounded mainly by APEC strains and by H-antigens from human E. coli, and another one compounded by commensal avian E. coli strains, S. enterica, and by other H-antigens from human E. coli. Overall, this work demonstrated that fliC conserved regions may be associated with pathogenic clones of APEC strains, and also shows a great similarity among APEC and H-antigens of E. coli strains isolated from humans. These data, can add evidence that APEC strains can exhibit a zoonotic risk.
2 citations