piperidines and Acinetobacter-Infections

The combination of cefepime and zidebactam (WCK5222), a novel β-lactam enhancer, has demonstrated activity against a wide variety of Gram-negative pathogens and is currently under clinical evaluation.. To examine the activity of cefepime/zidebactam against: (i) a contemporary collection of Gram-negative isolates from New York City; (ii) a collection of carbapenem-resistant clinical isolates; and (iii) a collection of isolates with characterized resistance mechanisms.. Susceptibility tests were performed using broth microdilution for cefepime, zidebactam and cefepime/zidebactam (1:1).. More than 99% of a contemporary collection of Escherichia coli, Klebsiella pneumoniae and Enterobacter spp. had cefepime/zidebactam MICs ≤2 mg/L, the susceptibility breakpoint for cefepime. For K. pneumoniae, the acquisition of blaKPC resulted in increased MICs, although MICs remained ≤2 mg/L for 90% of KPC-possessing isolates. Overall for Pseudomonas aeruginosa, 98% of isolates had MICs ≤8 mg/L and MICs were affected by increased expression of ampC. For carbapenem-resistant P. aeruginosa, 78% of isolates had cefepime/zidebactam MICs ≤8 mg/L. The activity of cefepime/zidebactam against Acinetobacter baumannii was lower, with 85% of all isolates and 34% of carbapenem-resistant isolates with MICs ≤8 mg/L (cefepime interpretative criteria).. Cefepime/zidebactam demonstrated excellent activity against Enterobacteriaceae and P. aeruginosa, although activity was reduced in carbapenem-non-susceptible isolates. The activity against A. baumannii was reduced and studies examining the therapeutic efficacy in strains with high cefepime/zidebactam MICs are warranted.

Topics: Acinetobacter baumannii; Acinetobacter Infections; Anti-Bacterial Agents; Azabicyclo Compounds; Cefepime; Cyclooctanes; Drug Interactions; Endemic Diseases; Enterobacteriaceae; Enterobacteriaceae Infections; Health Facilities; Humans; Microbial Sensitivity Tests; New York City; Piperidines; Pseudomonas aeruginosa; Pseudomonas Infections

Zidebactam is a β-lactam enhancer antibiotic with a dual mechanism of action involving binding to Gram-negative PBP2 and β-lactamase inhibition. Cefepime combined with zidebactam (WCK 5222) is under clinical development for treatment of Gram-negative infections.. To evaluate the in vitro activities of cefepime and zidebactam separately and combined at 1:1 and 2:1 ratios when tested against Gram-negative organisms producing the most clinically relevant β-lactamase types.. β-Lactamase-producing (193) and WT (71) isolates were tested for susceptibility by broth microdilution method against cefepime/zidebactam, cefepime and zidebactam.. Cefepime/zidebactam (1:1) was very active against Enterobacteriaceae producing CTX-M-15 (21; MIC 50/90 0.25/1 mg/L), SHV (20; MIC 50/90 0.12/0.25 mg/L), other ESBLs (20, including GES-18, OXA-1/30 and OXY-, PER-, TEM- and VEB-like; MIC 50/90 0.25/1 mg/L), plasmidic AmpC (10; MIC 50/90  ≤0.06/≤0.06 mg/L), derepressed AmpC (23; MIC 50/90 0.12/0.5 mg/L), KPC (35; MIC 50/90 0.25/1 mg/L) and metallo-β-lactamases (MBLs; 20 including VIM, IMP and NDM; MIC 50/90 0.5/8 mg/L). Cefepime/zidebactam (1:1) was also active against Pseudomonas aeruginosa with overexpression of AmpC (21; MIC 50/90 4/8 mg/L) and MBLs [12 (VIM and IMP); MIC 50/90 4/8 mg/L]. Zidebactam alone exhibited potent in vitro activity against some Enterobacteriaceae and P. aeruginosa , including β-lactamase-producing strains. Cefepime/zidebactam MIC values were lower than those of each agent tested alone for many β-lactamase-producing strains, indicating synergy. Cefepime/zidebactam showed moderate activity against OXA-23/24/58-producing Acinetobacter baumannii [MIC 50/90 32 mg/L (1:1)].. Cefepime/zidebactam showed potent activities against Enterobacteriaceae and P. aeruginosa producing various clinically relevant β-lactamases, including ESBLs, KPCs, AmpC and MBLs for which limited treatment options are currently available.

Topics: Acinetobacter baumannii; Acinetobacter Infections; Anti-Bacterial Agents; Azabicyclo Compounds; beta-Lactamase Inhibitors; beta-Lactamases; Cefepime; Cephalosporins; Cyclooctanes; Drug Synergism; Enterobacteriaceae; Enterobacteriaceae Infections; Humans; Microbial Sensitivity Tests; Piperidines; Pseudomonas aeruginosa; Pseudomonas Infections

Topics: Acinetobacter; Acinetobacter Infections; Australia; beta-Lactamase Inhibitors; beta-Lactamases; Carbapenems; DNA, Bacterial; Drug Resistance, Bacterial; Humans; Hydrolysis; Imidazoles; Piperidines