blaIMP and blaOXA mediated carbapenemase resistance in klebsiella pneumoniae: A molecular and phenotypic analysis

Abstract

These effusions result in a convergence of Class B metallo-2-lactamases (blaIMP) and Class D oxacillinases (blaOXA) in Klebsiella pneumoniae to produce very difficult to diagnose and treat complex multidrug-resistant phenotypes. Fifteen phenotypic susceptibility testing and multiplex PCR were performed on 185 carbapenem-resistant K. pneumoniae isolates of a tertiary care center to determine the prevalence and co-occurrence of blaIMP and blaOXA-48-like genes. Molecular genotyping revealed that blaOXA-48-like genes were present in 62.2% of isolates and blaIMP variants in 28.1% with 14.6% of the isolates carrying both genes, which increases the MIC values of imipenem and meropenem by a significant margin over single-gene carriers. Thus, data shows that the development of blaIMP and blaOXA-co-producing strains makes newer 2 2-lactam/2 2-lactamase combinations largely ineffective. This requires the immediate introduction of molecular surveillance and other therapeutic agents such as cefiderocol.