Evaluation of three commercial lateral flow immunoassays for the detection of KPC, VIM, NDM, IMP and OXA-48-like carbapenemases

The emergence and global dissemination of carbapenemaseproducing Gram-negative bacteria (CPGNB) pose a significant public health threat due to the limited therapeutic options for CPGNB infections, which are associated with high mortality rates and a considerable economic and societal burden. 1 Early identification of CPGNB is useful for timely infection prevention and control measures and therapeutic stewardship, and identification of the resistance mechanisms has become essential following the availability of several new antimicrobial agents with variable coverage depending on resistance mechanism. 2 Lateral flow immunoassays (LFIAs) are rapid (15-30 min) systems for detection of clinically relevant resistance mechanisms, including carbapenemases.LFIAs require limited technical expertise in the absence of expensive equipment, and are generally less expensive than genotypic methods. 3,4 Moreover, unlike the latter, LFIA systems detect proteins and are not affected by false positivity in case of silenced genes. 4 However, false negativity may also occur with LFIA systems in case of low level of production of the target protein (e.g. with weakly expressed MBLs), 5,6 or of amino acid changes in the epitopes of the target protein recognized by the antibody probe used by the system (e.g.changes at position 179 in the Ω-loop of KPC carbapenemase variants, which confer resistance to avibactam and exhibit impaired carbapenemase activity). [7][[9][10][11] In this work we evaluated three commercial LFIA systems for detection of the five most common families of carbapenemases encountered among CPGNB, namely the KPC/IMP/NDM/VIM/ OXA-48 Combo Test Kit (KINVO, Medomics Medical Technology, Jiangsu, China), the O.K.