E.G. Stehling,T.A. Campos,V. Azevedo, M. Brocchi and W.D. Silveira
Published May 25, 2007
Genet. Mol. Res. 6 (2): 331-337 (2007)

About the Authors
E.G. Stehling,T.A. Campos,V. Azevedo, M. Brocchi and W.D. Silveira

Corresponding author
W.D. Silveira
E-mail: wds@unicamp.br

ABSTRACT

A 43-MDa conjugative plasmid isolated from an avian septicemic Escherichia coli (APEC) strain possessing genes related to the adhesion and invasion capacities of in vitro-cultured cells was sequenced. The results demonstrated that the 43-MDa plasmid harbors bacterial pathogenicity-related sequences which probably allow the wildtype pathogenic strain to adhere to and invade tissues and to cause septicemia in poultry. The existence of homology sequences to sequences belonging to other human pathogenic Enterobacteriaceae like Escherichia coli O157:H7, Shigella and Salmonella was also observed. The presence of these sequences in this plasmid could indicate that there is horizontal genetic transfer between bacterial strains isolated from different host species. In conclusion, the present study suggests that APEC strains harbor high-molecular weight plasmids that present pathogenicity- related sequences and that these are probably responsible for thepathogenicity exhibited by these strains. The presence of human pathogenicity- associated sequences in APEC conjugative plasmids suggests that these strains could represent a zoonotic risk.

Key words: Avian, Escherichia coli, Plasmids, Adhesion.