Rapid detection of the O25b-ST131 clone of Escherichia coli encompassing the CTX-M-15-producing strains

Olivier Clermont, Hiran Dhanji, Mathew Upton, Tarek Gibreel, Andrew Fox, David Boyd, Michael R. Mulvey, Patrice Nordmann, Etienne Ruppé, Jean Louis Sarthou, Thierry Frank, Sophie Vimont, Guillaume Arlet, Catherine Branger, Neil Woodford, Erick Denamur*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

290 Citations (Scopus)


Objectives: Recently, a CTX-M-15 extended-spectrum β-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 totalof 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.

Original languageEnglish
Pages (from-to)274-277
Number of pages4
JournalJournal of Antimicrobial Chemotherapy
Issue number2
Publication statusPublished - 2009

Bibliographical note

Funding Information:
This work was partially funded by a ‘Contrat d’Initiation à la Recherche Clinique’ CRC 05103 (Assistance Publique, Hôpitaux de Paris) and the ‘Fondation pour la Recherche Médicale’.


  • B2 phylogenetic subgroup I
  • ESBL
  • O25
  • ST 131


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