Efficient direct extended-spectrum β-lactamase detection by multiplex real-time PCR: accurate assignment of phenotype by use of a limited set of genetic markers.

The number and diversity of genes potentially complicate genetic approaches to the rapid detection of transmissible extended-spectrum β-lactamase genes. We developed a robust multiplexed real-time PCR assay based on targets identified in a prior survey and used this to detect relevant genes in 617 consecutive clinical isolates of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae.