Avibactam sodium (NXL-104) dihydrate inhibits CTX-M-15 and β-lactamase TEM-1 with IC 50 s of 5 nM and 8 nM, respectively. Avibactam sodium dihydrate is a reversible and covalent inhibitor of non-β-lactam β-lactamase [1].

Avibactam is a molecule with little antibacterial activity, that inhibits class A and C β-lactamases, but not metallo types and Acinetobacter OXA carbapenemases [2]. Ceftazidime -Avibactam (0-256 mg/L) inhibits 16 bla KPC-2 positive and 1 of bla OXA-232 positive Klebsiella pneumonia growth with MIC 50 and MIC 90 for both 8 mg/L [4].

Ceftazidime-Avibactam (0.375 mg/g; s.c.; q8h for 10 days) has a significant effect on the bacteria and led to a certain therapeutic efficacy in K. pneumoniae strain Y8 infected mouse model [3]. Avibactam (64 mg/kg; s.c.; once) shows mean estimated half-life in plasma in the terminal phase of 0.24 h in Pseudomonas aeruginosa infected neutropenic mice with lung infection [3]. Animal Model: Six-week-old BALB/c mice (female), K. pneumoniae strain Y8 infection model [4] Dosage: 0.375 mg/g in combination with Ceftazidime Administration: Subcutaneous injection, 4 h post infection and given every 8 h for 10 days Result: 70% of infection group mice died within 4 days, and all mice in the PBS group died within 13 days. All treatment group mice survived at 10 days post infection with the antibiotic applied every 8 h, whereas 100% of mice in this group died within 4 days after the antibiotic treatment stopped. The spleen and liver of treatment group mice showed lower CFU counts, as compare with that of infected group.