Synergy and Mode of Action of Ceftazidime plus Quercetin or Luteolin on Streptococcus pyogenes

Figure 7

PCA results (a), the loading plot of the 1st (PC1) and the 2nd (PC2) principal components obtained from PCA of S. pyogenes DMST 30653 (b), the representative 2nd derivative transformation spectra (1800–1000 cm⁻¹) (c), and the representative 2nd derivative transformation spectra (3000–2800 cm⁻¹) (d). Symbols represent the FT-IR spectra of Con = control (drugs free); Cef (0.25) = 0.25 μg mL⁻¹ ceftazidime; Cef (0.09) + Lut (12) = ceftazidime 0.09 μg mL⁻¹ plus luteolin 12 μg mL⁻¹; Cef (0.09) + Que (3) = ceftazidime 0.09 μg mL⁻¹ plus quercetin 3 μg mL⁻¹. The investigation was performed in three studies and all data are displayed as the mean of three experiments.

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