Specific detection of blaVIM and blaIMP metallo-β-lactamase genes in a single real-time PCR

This study describes the development of a real-time PCR protocol for rapid detection of the most common bla(VIM) (bla(VIM-1), bla(VIM-2), bla(VIM-3), bla(VIM-4), bla(VIM-5), bla(VIM-6), bla(VIM-10), bla(VIM-11), bla(VIM-12)) and bla(IMP) (bla(IMP-1), bla(IMP-2), bla(IMP-6), bla(IMP-8), bla(IMP-10), bla(IMP-15), bla(IMP-19), bla(IMP-20)) genes in a single reaction. The genes were specifically detected and clearly differentiated into four groups, i.e., (i) bla(VIM-1)-like (bla(VIM-1), bla(VIM-4), bla(VIM-5), bla(VIM-12)); (ii) bla(VIM-2)-like (bla(VIM-2), bla(VIM-3), bla(VIM-6), bla(VIM-10), bla(VIM-11)); (iii) bla(IMP-1)-like (bla(IMP-1), bla(IMP-6), bla(IMP-10)); and (iv) bla(IMP-2)-like (bla(IMP-2), bla(IMP-8), bla(IMP-15), bla(IMP-19), bla(IMP-20)), by melting curve analysis of the real-time PCR products. The protocol was used to screen positive bla(VIM-1), bla(VIM-2) and bla(IMP-1) control strains, 70 Gram-negative isolates resistant to carbapenems, and 30 Gram-negative isolates susceptible to carbapenems (negative controls).