Checkerboard MIC and Effect Model analysis
The β-lactamase genotype of each bacterial strain and the MIC values of
aztreonam/nacubactam alone and nacubactam MIC in the presence of 4 mg
L-1 of aztreonam for each bacterial strain are shown
in Table 1. Fig. 2 shows the dose-response relationship of aztreonam MIC
to nacubactam concentration for each strain analysed by the Inhibitory
Effect Sigmoid I max Model. All strains were
resistant to aztreonam alone, but the combination of aztreonam and
nacubactam decreased MIC in a nacubactam concentration-dependent
manner. Interestingly, nacubactam
alone also showed slight antibacterial activity against all bacterial
strains.