title: Emergence of human pandemic O25:H4-ST131 CTX-M-15 extended-spectrum-beta-lactamase-producing Escherichia coli among companion animals.
abstract: OBJECTIVE
  In view of the intercontinental emergence of Escherichia coli clone O25:H4-ST131 producing CTX-M-15 extended-spectrum beta-lactamase (ESBL) in human clinical settings it would be of great interest to explore its existence in animals to unravel a possible reservoir function and the origin and transmission of this group of multiresistant strains.
  
  
  METHODS
  A total of 177 clinical phenotypically ESBL-producing E. coli isolates, mainly obtained from companion animals with urinary tract infections, wound infections and diarrhoea, were collected in a veterinary diagnostic laboratory covering a European-wide service area. They were screened for molecular subtype O25b and multilocus sequence type 131. O25b-ST131 isolates were subsequently tested for ESBL types, and phenotypic and genotypic resistance determinants. Further characterization of the strains was performed by PFGE and virulence gene typing.
  
  
  RESULTS
  Ten (5.6%) of 177 phenotypically ESBL-producing E. coli isolates, nine strains from dogs and one strain from a horse, were allocated to the B2-O25b-ST131 lineage. Nine of these isolates harboured a CTX-M-15-type beta-lactamase enzyme while one strain possessed an SHV-12-type ESBL. Macrorestriction analysis revealed a cluster formation of six of the animal CTX-M-15-type ESBL-producing strains from five different European countries together with a human control strain constituting a group of clonally related strains at a similarity value of 87.0%.
  
  
  CONCLUSIONS
  Our findings demonstrate that the group of clonally related human B2-O25:H4-ST131 CTX-M-15-type ESBL-producing E. coli strains is present in companion animals from various European countries. This highlights the possibility of inter-species transmission of these multiresistant strains from human to animal and vice versa.
authors.affiliation: Institute of Microbiology and Epizootics, Freie Universität Berlin, Philippstr. 13, 10115 Berlin, Germany. ewers.christa@vetmed.fu-berlin.de
authors.forename: Christa
authors.initials: C
authors.lastname: Ewers
authors.forename: Mirjam
authors.initials: M
authors.lastname: Grobbel
authors.forename: Ivonne
authors.initials: I
authors.lastname: Stamm
authors.forename: Peter A
authors.initials: PA
authors.lastname: Kopp
authors.forename: Ines
authors.initials: I
authors.lastname: Diehl
authors.forename: Torsten
authors.initials: T
authors.lastname: Semmler
authors.forename: Angelika
authors.initials: A
authors.lastname: Fruth
authors.forename: Janine
authors.initials: J
authors.lastname: Beutlich
authors.forename: Beatriz
authors.initials: B
authors.lastname: Guerra
authors.forename: Lothar H
authors.initials: LH
authors.lastname: Wieler
authors.forename: Sebastian
authors.initials: S
authors.lastname: Guenther
mesh_terms: D000818:Animals; D000829:Animals, Domestic / Q000382:microbiology*; D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004196:Disease Outbreaks; D004926:Escherichia coli / Q000145:classification* / Q000201:enzymology*; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D029968:Escherichia coli Proteins / Q000235:genetics; D005060:Europe / Q000453:epidemiology; D005838:Genotype; D006736:Horses; D006801:Humans; D008826:Microbial Sensitivity Tests; D017422:Sequence Analysis, DNA; D012703:Serotyping; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D029968:Escherichia coli Proteins; C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases