CARBA SMART selective chromogenic media (bioMérieux, Italy) was used to screen for carbapenemase-producing Enterobacterales. Colonies detected on CARBA SMART were identified with matrix-assisted laser desorption/ionization–time of flight mass spectrometry (MALDI-TOF MS; Bruker Daltonics). According to routine hospitals’ microbiology laboratory protocol implemented to speed up the diagnostic procedures for positive BCs, bacterial pellet obtained from positive BCs was used for bacterial identification by MALDI-TOF MS (Bruker Daltonics). Antimicrobial susceptibility testing was performed with the Vitek 2 automated system (bioMérieux), the SensiTitre system (Thermo Fisher Scientific), or ITGN Micronaut panels (Diagnostika GmbH, now a company of Bruker Daltonics) run on MICRO MIB (Bruker Daltonics), as appropriate.
Subsequent molecular analysis for the search of blaKPC gene was performed for all the strains by the GeneXpert System (Cepheid). When available, details of KPC variants were retrieved according to recently published studies [15 (link), 21 (link), 38–40 ]. As previously reported, strains positive for a blaKPC gene but negative with lateral flow immunoassays (LFIAs) for carbapenemase detection were presumptively considered KPC-31–producing KPC-Kp and defined as KPC-31-like–producing KPC-Kp [41 (link)].
Subsequent molecular analysis for the search of blaKPC gene was performed for all the strains by the GeneXpert System (Cepheid). When available, details of KPC variants were retrieved according to recently published studies [15 (link), 21 (link), 38–40 ]. As previously reported, strains positive for a blaKPC gene but negative with lateral flow immunoassays (LFIAs) for carbapenemase detection were presumptively considered KPC-31–producing KPC-Kp and defined as KPC-31-like–producing KPC-Kp [41 (link)].