A TaqMan real-time PCR assay for detection of qacEd1 gene in Gram-negative bacteria

The transfer of biocide and antibiotic resistance genes by mobile genetic elements is the most common mechanism for rapidly acquiring and spreading resistance among bacteria. The qacEd1 gene confers the resistance to quaternary ammonium compounds (QACs). It has also been considered a genetic marker for the presence of class 1 integrons associated with multidrug-resistant (MDR) phenotypes in Gram-negative bacteria. In this study, a TaqMan real-time PCR assay was developed to detect the qacEd1 gene in Gram-negative bacteria. The assay has a detection limit of 80 copies of the qacEd1 gene per reaction. No false-positive or false-negative results have been observed. Simultaneous amplification and detection of the 16S rRNA gene is performed as an endogenous internal amplification control (IAC). The TaqMan real-time PCR assay developed is a rapid, sensitive, and specific method that could be used to monitor resistance to QACs, the spread of class 1 integrons, and the prediction of associated MDR phenotypes in Gram-negative bacteria.