Rapid detection of the O25b-ST131 clone of Escherichia coli encompassing the CTX-M-15-producing strains.
OBJECTIVE
Recently, a CTX-M-15 extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli O25b-ST131 clone, belonging to the B2 phylogenetic group and with a high virulence potential, has been reported all over the world, representing a major public health problem. The present study was carried out to develop a rapid and simple detection assay that identifies members of this clone.


METHODS
A total of 627 E. coli isolates of which 373 produced an ESBL, collected across four continents, were screened using a O25b-ST131 clone allele-specific PCR for the pabB gene.


RESULTS
One hundred and forty-three ESBL isolates were found positive with the assay. These isolates were all of O25b type and, when studied by multilocus sequence typing (25 cases), were all of ST131. The O25b-ST131 clone was found to produce ESBLs other than CTX-M-15, specifically CTX-M-2, -3, -14, -27, -32 and -61 as well as TEM-24. This clone represents 3% of non-ESBL B2 isolates originating from urinary tract infections in Paris.


CONCLUSIONS
We have developed a PCR-based assay that easily identifies a clone with high likelihood of producing ESBLs, including CTX-M-15.
Clermont
Olivier
O
INSERM U722 and Université Paris 7, Faculté de Médecine, Site Xavier Bichat, 75018 Paris, France.
Dhanji
Hiran
H
Upton
Mathew
M
Gibreel
Tarek
T
Fox
Andrew
A
Boyd
David
D
Mulvey
Michael R
MR
Nordmann
Patrice
P
Ruppé
Etienne
E
Sarthou
Jean Louis
JL
Frank
Thierry
T
Vimont
Sophie
S
Arlet
Guillaume
G
Branger
Catherine
C
Woodford
Neil
N
Denamur
Erick
E
D004926:Escherichia coli / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000175:diagnosis* / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics; D006801:Humans; D010297:Paris; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
D029968:Escherichia coli Proteins; C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases