The carbapenemase menace: do dual mechanisms code for more resistance?

For bacterial identification, susceptibility testing was performed as per Clinical and Laboratory Standards Institute guidelines2 of 2013 and the E-test was performed as per manufacturer’s instructions. An in-house multiplex polymerase chain reaction test was designed to identify the predominant carbapenemases blaNDM, blaOXA, blaKPC, blaVIM, and blaIMP.3 Of the 74 clinical isolates, 32 (43%) consisted of Klebsiella spp., 25 (34%) of Enterobacter spp., and 17 (23%) of Escherichia coli. [...]most isolates with dual carbapenemase producers (New Delhi Metallo-beta-lactamase-1 together with Oxacillinase 48/181 and New Delhi Metallo-beta-lactamase-1 together with Verona integron-encoded metallo-β-lactamase) had minimum inhibitory concentration values greater than 32 µg/mL.