Real-time PCR for detection of the O25b-ST131 clone of Escherichia coli and its CTX-M-15-like extended-spectrum β-lactamases

CTX-M-15 has become the most prevalent extended-spectrum β-lactamase amongst Escherichia coli in many countries during the past decade. Its dominance partly reflects the dissemination of an E. coli O25b:H4 ST131 clone that commonly produces this enzyme. We describe rapid real-time polymerase chain reaction (PCR) assays able to detect E. coli belonging to the ST131 clone and to identify blaCTX-M-15-like.