Systematic evaluation of in vitro pharmacodynamic drug interactions of ceftazidime/avibactam and fosfomycin in E. coli

Combination therapy can increase efficacy of antibiotics and prevent against emergence of resistance. Ceftazidime/avibactam and fosfomycin is empirically combined for this purpose, but a systematic and quantitative evaluation of thise combination is lacking. In this study, a systematic analysis of the pharmacodynamic interactions of ceftazidime/avibactam and fosfomycin in clinical and isogenic E. coli strains carrying genes coding for several carbapenemases or ESBLs was performed and pharmacodynamic interactions were quantified by modelling and simulations.