title: Extended-spectrum β-lactamase-producing Escherichia coli isolated from poultry: a review of current problems, illustrated with some laboratory findings.
abstract: Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli has been documented in humans as well as in food-producing birds, including chickens, and for unknown reasons the prevalence has increased significantly during the last decade. With E. coli as a major opportunistic pathogen in chickens and with a potential for zoonotic transfer to human beings, ESBL-producing E. coli represents a major risk both to poultry production and to human health. This review presents some of the current problems with ESBL-producing E. coli in relation to poultry production, with a focus on chickens. To illustrate issues in relation to screening and typing, two case studies are included where one collection of ESBL-producing E. coli isolates was obtained from asymptomatic carrier chickens while the other was obtained from lesions in chickens. Pulsed-field gel electrophoresis and multi-locus sequence typing revealed a highly heterogeneous population of ESBL-producing E. coli. All isolates harboured between one and three large plasmids (>100 kb). Among isolates associated with asymptomatic chickens, the ESBL types SHV and TEM dominated, while CTX-M-1 dominated in disease-associated isolates. The isolates from diseased birds were occasionally of sequence types often associated with human infections, such as ST131. With improved tools to trace and screen for ESBL-producing E. coli at farm level, strategies can be selected that aim to reduce or eliminate the presence of ESBL-producing E. coli in poultry and poultry products meant for human consumption.
authors.affiliation: a Department of Veterinary Disease Biology, Faculty Health and Medicine , University of Copenhagen , Frederiksberg C , Denmark.
authors.forename: Rikke H
authors.initials: RH
authors.lastname: Olsen
authors.forename: Magne
authors.initials: M
authors.lastname: Bisgaard
authors.forename: Ulrich
authors.initials: U
authors.lastname: Löhren
authors.forename: Brice
authors.initials: B
authors.lastname: Robineau
authors.forename: Henrik
authors.initials: H
authors.lastname: Christensen
mesh_terms: D000818:Animals; D002511:Cephalosporins; D002645:Chickens / Q000382:microbiology*; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D005838:Genotype; D006801:Humans; D058885:Multilocus Sequence Typing; D010957:Plasmids / Q000235:genetics; D011201:Poultry Diseases / Q000382:microbiology* / Q000635:transmission; D017422:Sequence Analysis, DNA; D014774:Virulence; D015047:Zoonoses; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D002511:Cephalosporins; D001618:beta-Lactamases