Avibactam is a suicide inhibitor of β-lactamase enzymes, so it saves the amoxycillin, which is a suicide inhibitor of penicillin binding proteins

Both of these compounds are β-lactams and inhibit penicillin binding proteins, but by binding at different sites, so they act synergistically

Amoxycillin is a β-lactam antibiotic while avibactam is a protein synthesis inhibitor, so they act synergistically

Amoxycillin is a suicide inhibitor of β-lactamase enzymes, so it saves the avibactam which is a suicide inhibitor of penicillin binding protein