title: In situ ESBL conjugation from avian to human Escherichia coli during cefotaxime administration.
abstract: OBJECTIVE
  The behaviour of an Escherichia coli isolate of broiler origin harbouring a bla(TEM-52) -carrying plasmid (lactose-negative mutant of B1-54, IncII group) was studied in an in situ continuous flow culture system, simulating the human caecum and the ascending colon during cefotaxime administration.
  
  
  RESULTS
  Fresh faeces from a healthy volunteer, negative for cephalosporin-resistant E. coli, were selected to prepare inocula. The microbiota was monitored by plating on diverse selective media, and a shift in the populations of bacteria was examined by 16S rDNA PCR denaturing gradient gel electrophoresis. Escherichia coli transconjugants were verified by plasmid and pulsed-field gel electrophoresis profiles (PFGE). The avian extended-spectrum β-lactamase-positive E. coli was able to proliferate without selective pressure of cefotaxime, and E. coli transconjugants of human origin were detected 24 h after inoculation of the donor strain. Upon administration of cefotaxime to the fresh medium, an increase in the population size of E. coli B1-54 and the transconjugants was observed. PFGE and plasmid analysis revealed a limited number of human E. coli clones receptive for the bla(TEM-52) -carrying plasmid.
  
  
  CONCLUSIONS
  These observations provide evidence of the maintenance of an E. coli strain of poultry origin and the horizontal gene transfer in the human commensal bowel microbiota even without antimicrobial treatment.
  
  
  CONCLUSIONS
  The fact that an E. coli strain of poultry origin might establish itself and transfer its bla gene to commensal human E. coli raises public health concerns.
authors.affiliation: Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan, Merelbeke, Belgium. Annemieke.Smet@Ugent.be
authors.forename: A
authors.initials: A
authors.lastname: Smet
authors.forename: G
authors.initials: G
authors.lastname: Rasschaert
authors.forename: A
authors.initials: A
authors.lastname: Martel
authors.forename: D
authors.initials: D
authors.lastname: Persoons
authors.forename: J
authors.initials: J
authors.lastname: Dewulf
authors.forename: P
authors.initials: P
authors.lastname: Butaye
authors.forename: B
authors.initials: B
authors.lastname: Catry
authors.forename: F
authors.initials: F
authors.lastname: Haesebrouck
authors.forename: L
authors.initials: L
authors.lastname: Herman
authors.forename: M
authors.initials: M
authors.lastname: Heyndrickx
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002432:Cecum / Q000382:microbiology; D002439:Cefotaxime / Q000494:pharmacology; D003106:Colon / Q000382:microbiology; D003227:Conjugation, Genetic; D058645:Denaturing Gradient Gel Electrophoresis; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification; D022761:Gene Transfer, Horizontal; D006801:Humans; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D011200:Poultry / Q000382:microbiology*; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; C445691:TEM-52 beta-lactamase; D001618:beta-Lactamases; D002439:Cefotaxime