Emergence of human pandemic O25:H4-ST131 CTX-M-15 extended-spectrum-beta-lactamase-producing Escherichia coli among companion animals.
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.
Ewers
Christa
C
Institute of Microbiology and Epizootics, Freie Universität Berlin, Philippstr. 13, 10115 Berlin, Germany. ewers.christa@vetmed.fu-berlin.de
Grobbel
Mirjam
M
Stamm
Ivonne
I
Kopp
Peter A
PA
Diehl
Ines
I
Semmler
Torsten
T
Fruth
Angelika
A
Beutlich
Janine
J
Guerra
Beatriz
B
Wieler
Lothar H
LH
Guenther
Sebastian
S
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*
D029968:Escherichia coli Proteins; C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases