Antimicrobial Resistance Surveillance Protocol

Blood samples were processed using the BACTEC 9240 system or Bactec FX system (Becton-Dickinson Microbiology Systems), with an incubation period of 5 d. Isolates were identified using MALDI-TOF mass spectrometry, which was supplemented with biochemical reactions during the first 2 yr for additional confirmation. Antimicrobial susceptibility testing was performed using a microdilution system (Phoenix system, Becton Dickinson, Franklin Lakes, NJ) or the Etest (AB Biodisk, Solna, Sweden/bioMérieux, Mercy l’Etoile, France). ESBL-producing bacteria were suspected by MIC results and confirmed by a double-disc synergy test (15 (link)). Carbapenemase-producing Enterobacterales were phenotypically detected by the modified carbapenem inactivation method (mCIM) (16 (link)), in combination with the NG-Test CARBA 5 lateral flow immunoassay (NG Biotech, France) to detect the five most prevalent carbapenemases (KPC, OXA-48-like, VIM, IMP, and NDM) (17 (link)). Current EUCAST breakpoints for each year were used to define susceptibility or resistance to these antimicrobial agents, and intermediate susceptibility was considered as resistance.