1. Academic Validation
  2. Assessment of Activity and Resistance Mechanisms to Cefepime in Combination with the Novel β-Lactamase Inhibitors Zidebactam, Taniborbactam, and Enmetazobactam against a Multicenter Collection of Carbapenemase-Producing Enterobacterales

Assessment of Activity and Resistance Mechanisms to Cefepime in Combination with the Novel β-Lactamase Inhibitors Zidebactam, Taniborbactam, and Enmetazobactam against a Multicenter Collection of Carbapenemase-Producing Enterobacterales

  • Antimicrob Agents Chemother. 2022 Feb 15;66(2):e0167621. doi: 10.1128/AAC.01676-21.
Juan Carlos Vázquez-Ucha  # 1 Cristina Lasarte-Monterrubio  # 1 Paula Guijarro-Sánchez  # 1 Marina Oviaño 1 Laura Álvarez-Fraga 1 Isaac Alonso-García 2 Jorge Arca-Suárez 1 German Bou  # 1 Alejandro Beceiro  # 1 GEMARA-SEIMC/REIPI Enterobacterales Study Group
Affiliations

Affiliations

  • 1 Servicio de Microbiología do Complejo Hospitalario Universitario da Coruña (CHUAC), Instituto de Investigación Biomédica da Coruña (INIBIC), Coruña, CIBER de Enfermedades Infecciosas, Spain.
  • 2 Servicio de Microbiología, Hospital Provincial Pontevedra, Pontevedra, Spain.
  • # Contributed equally.
Abstract

The global distribution of carbapenemases such as KPC, OXA-48, and metallo-β-lactamases (MBLs) gives cause for concern, as these enzymes are not inhibited by classical β-lactamase inhibitors (BLIs). The current development of new inhibitors is one of the most promising highlights for the treatment of multidrug-resistant bacteria. The activity of cefepime in combination with the novel BLIs zidebactam, taniborbactam, and enmetazobactam was studied in a collection of 400 carbapenemase-producing Enterobacterales (CPE). The genomes were fully sequenced and potential mechanisms of resistance to cefepime/BLI combinations were characterized. Cefepime resistance in the whole set of isolates was 79.5% (MIC50/90 64/≥128mg/L). The cefepime/zidebactam and cefepime/taniborbactam combinations showed the highest activity (MIC50/90 ≤0.5/1 and ≤0.5/2 mg/L, respectively). Cefepime/zidebactam displayed high activity, regardless of the carbapenemase or extended-spectrum β-lactamase (ESBL) considered (99% of isolates displayed MIC ≤2 mg/L). Cefepime/taniborbactam displayed excellent activity against OXA-48- and KPC-producing Enterobacterales and lower activity against MBL-producing isolates (four strains yielded MICs ≥16 mg/L: 2 NDM producers with an insertion in PBP3, one VIM-1 producer with nonfunctional OmpK35, and one IMP-8 producer). Cefepime/enmetazobactam displayed the lowest activity (MIC50/90 1/≥128 mg/L), with MICs ≥16 mg/L for 49 MBL producers, 40 OXA-48 producers (13 with amino acid changes in OmpK35/36, 4 in PBPs and 11 in RamR) and 25 KPC producers (most with an insertion in OmpK36). These results confirm the therapeutic potential of the new β-lactamase inhibitors, shedding LIGHT on the activity of cefepime and BLIs against CPE and resistance mechanisms. The cefepime/zidebactam and cefepime/taniborbactam combinations are particularly highlighted as promising alternatives to penicillin-based inhibitors for the treatment of CPE.

Keywords

antimicrobial resistance; carbapenemase-producing Enterobacterales; cefepime; enmetazobactam; restoring antimicrobial activity; restoring antimicrobial efficacy; taniborbactam; zidebactam; β-lactamase inhibitors.

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