Activity of Novel Ceftibuten-Avibactam, Ceftazidime-Avibactam, and Comparators Against a Challenge Set of Enterobacterales from Outpatient Centers and Nursing Homes Across the United States (2022-2024)

Ceftibuten is being developed in combination with the oral prodrug of avibactam. Outpatient isolates (n = 500) from 11 US states underwent susceptibility testing with manual broth microdilution. Ceftibuten had susceptibility rates of 64% (CLSI) and 23% (EUCAST). Ceftibuten-avibactam achieved 96.4% inhibition at MIC ≤ 1 µg/mL. Susceptibility rates were as follows: cefpodoxime (2.6%), ceftriaxone (1%), ceftazidime-avibactam (99.6%), tebipenem (89%), ertapenem (94.4%), levofloxacin (26.6%), trimethoprim-sulfamethoxazole (40.2%), and fosfomycin (96.8%). Ceftibuten-avibactam demonstrates potent in vitro activity against cephalosporin non-susceptible isolates.