Fig. 3

NagZ complementation can rescue induction of AmpC and resistance by subinhibitory concentration CFZ (256 μg/ml) and IMP (0.125 μg/ml) in ΔnagZ. RT-qPCR (A) and cropped western blot (B) verified that the NagZ complementation model was successfully generated. C mRNA expressions of ampC were identified using RT-qPCR in ΔnagZ, ΔnagZ complemented with NagZ (ΔnagZ + NagZ), ΔnagZ + NagZ treated with CFZ (ΔnagZ + NagZ + CFZ) and ΔnagZ + NagZ treated with IMP (ΔnagZ + NagZ + IMP). D Western blot (cropped blots) was employed for the determination of ampC protein expressions in ΔnagZ, ΔnagZ + NagZ, ΔnagZ + NagZ + CFZ, and ΔnagZ + NagZ + IMP strains. E Western blot Quantitative analysis (D), and the internal control employed was DnaK. F Nitrocefin hydrolysis assay in nagZ, ΔnagZ + NagZ, ΔnagZ + NagZ + CFZ and ΔnagZ + NagZ + IMP was used for the analysis of AmpC β-lactamase activity. ** P < 0.01 indicates high statistical significance