Acquisition of Avian PathogenicEscherichia coliPlasmids by a CommensalE. coliIsolate Enhances Its Abilities To Kill Chicken Embryos, Grow in Human Urine, and Colonize the Murine Kidney

Abstract

We have found an avian pathogenic Escherichia coli (APEC) plasmid, pAPEC-O2-ColV, which contains many of the genes associated with APEC virulence and also shows similarity in content to a plasmid and pathogenicity island of human uropathogenic E. coli (UPEC). To test the possible role of this plasmid in virulence, it was transferred by conjugation along with a large R plasmid, pAPEC-O2-R, into a commensal avian E. coli strain. The transconjugant was compared to recipient strain NC, UPEC strain HE300, and donor strain APEC O2 using various assays, including lethality for chicken embryos, growth in human urine, and ability to cause urinary tract infection in mice. The transconjugant killed significantly more chicken embryos than did the recipient. In human urine, APEC O2 grew at a rate equivalent to that of UPEC strain HE300, and the transconjugant showed significantly increased growth compared to the recipient. The transconjugant also significantly outcompeted the recipient in colonization of the murine kidney. These findings suggest that APEC plasmids, such as pAPEC-O2-ColV, contribute to the pathogenesis of avian colibacillosis. Moreover, since avian E. coli and their plasmids may be transmitted to humans, evaluation of APEC plasmids as possible reservoirs of urovirulence genes for human UPEC may be warranted.

Resistência antimicrobiana e perfil plasmidial de Escherichia coli isolada de frangos de corte e poedeiras comerciais no Estado de Pernambuco

“…Isolados APEC também podem representar risco zoonótico para seres humanos, devido à presença, nos mesmos, de genes de virulência encontrados em E.coli patogênicas (causadoras de infecção do trato urinário e meningite em recém-nascidos) para seres humanos (Skyberg et al 2006).…”

Colibacillosis in poultry: unravelling the molecular basis of virulence of avian pathogenicEscherichia coliin their natural hosts

“…Transformation of an avirulent wild-type E. coli strain with a recombinant plasmid (pHK11) encoding for colicin V led to increased colonization of the chicken trachea (Wooley et al, 1998). Recently, transferring 2 APEC plasmids (ColV and large R) into a commensal E. coli strain by conjugation enhanced its abilities to kill chicken embryos, grow in human urine and colonize the murine kidney (Skyberg et al, 2006). Based on a selection of common traits that include plasmid-borne traits, two multiplex polymerase chain reaction (PCR) protocols have recently been described for the identification of APEC Ewers et al, 2005).…”

“…Recently, these genes have been mapped to a conserved region of a 93 kb cluster of putative virulence genes on a ColV plasmid, pAPEC-O2-ColV . Transforming an avian commensal E. coli strain with this plasmid led to a significant increase in the strain's lethality for chicken embryos and ability to colonize the murine kidney (Skyberg et al, 2006). Besides aerobactin, other iron acquisition and transport systems carried on the ColV plasmid include the salmochelin siderophore system (encoded by the iroBC-DEN locus), sitABC iron transport systems and a putative iron transport system novel to APEC (eit) .…”

Recombinant Iss as a Potential Vaccine for Avian Colibacillosis

“…Johnson et al (19,22) showed that iss occurs on a conserved virulence cluster found on conjugative ColV and ColBM plasmids of APEC isolates. Skyberg et al (42) found that transfer of these virulence plasmids to commensal E. coli increased the recipient strains' ability to grow in human urine and to colonize the kidney of mice. In order to follow up on this observation, Johnson et al (20) sequenced the entire genome of APEC O1 (an O1:K1:H7 strain) and compared it to other known E. coli genomes.…”