Multiplex PCR amplification assay for the detection of blaSHV, blaTEM and blaCTX-M genes in Enterobacteriaceae

Extended‐spectrum β‐lactamases (ESBLs) are often mediated by bla‐SHV, blaTEM and blaCTX‐M genes in Enterobacteriaceae and other Gram‐negative bacteria. Numerous molecular typing methods, including PCR‐based assays, have been developed for their identification. To reduce the number of PCR amplifications needed we have developed a multiplex PCR assay which detects and discriminates between bla‐SHV, blaTEM and blaCTX‐M PCR amplicons of 747, 445 and 593 bp, respectively. This multiplex PCR assay allowed the identification of bla‐SHV, blaTEM and blaCTX‐M genes in a series of clinical isolates of Enterobacteriaceae with previously characterised ESBL phenotype. The presence of blaSHV, blaTEM and blaCTX‐M genes was confirmed by partial DNA sequence analysis. Apparently, the universal well‐established CTX‐M primer pair used here to reveal plasmid‐encoded blaCTX‐M genes would also amplify the chromosomally located K‐1 enzyme gene in all Klebsiella oxytoca strains included in the study.