Inhibition of <i>Staphylococcus aureus</i> Biofilm Formation by Plumbagin Combined With Ceftazidime and Cefazolin

ABSTRACT Biofilm‐forming Staphylococcus aureus is the major cause several foodborne diseases, and pose a serious challenge in the healthcare, and food industry. Therefore, safe and effective antibiofilm strategies are needed to inhibit bacterial attachment in the food processing as well as for the treatment of infections. In the current study, we investigated the synergistic effect of plumbagin with ceftazidime, and cefazoline against biofilm formation by S. aureus . Plumbagin combined with ceftazidime, and cefazoline, had exhibited synergistic bactericidal effect on S. aureus , inhibiting over 80% of the biofilm formation, and reduced over 3 log 10 CFU/mL of bacterial cells, as compared to individual compounds. Scanning electron microscopy (SEM) images indicated that the combination of plumbagin with ceftazidime, and cefazolin, strongly inhibited the adherent cells of S. aureus . The amount of exopolysaccharides significantly decreased ( p &lt; 0.001) by treatment with plumbagin‐ceftazidime and cefazolin‐plumbagin combinations, whereas, the amount of exopolysaccharides production reduced to 28.29 μg glucose/mg biofilm, and 22.65 μg glucose/mg biofilm, respectively, as compared to untreated cells (65 μg glucose/mg biofilm). Furthermore, plumbagin in combination with cefazolin, significantly inhibited eDNA, and increased the production of reactive oxygen species (ROS) in S. aureus cells. This led to our finding suggests that these combinations can be used in food industry as well as in the treatment of infections.