Synergistic anti-biofilm effects of black cumin (Bunium persicum) extract and Halomonas-derived biosurfactant against multidrug-resistant pathogens

Background: The development of a multi-layered biofilms will lead to the spread of antibiotic resistance and protection of pathogenic bacteria. Biofilms containing antibiotic resistance genes are responsible for the emergence of multidrug-resistant bacteria. one way to combat bacteria that form biofilm is use natural antimicrobial such as plant extracts and biosurfactants The purpose of the study was to investigate the antibacterial and anti-biofilm properties of extract of black cumin (Bunium persicum) in combination with the biosurfactant produced by the Halomonas sp. strain against biofilm pathogenic bacteria, including methicillin-resistant Staphylococcus aureus, Escherichia coli, Bacillus cereus and Acinetobacter baumannii. Methods: The effect of microbial susceptibility testing for B. persicum extract and Halomonas-derived biosurfactant was assessed by disk diffusion and well diffusion. The effect of antimicrobial compounds in three phases, inhibition of biofilm formation, effect of destruction of established biofilm and inhibition of metabolic activity of biofilms was measured using a 96-well microtiter plate. Results: The minimum inhibitory concentration (MIC) of synergies between B. persicum extract and Halomonas-derived biosurfactant against E. coli and A. baumannii were lower than the MIC of the biosurfactant from Halomonas sp. strain. B. persicum extract significantly (P < 0.05) inhibited the formation of biofilms of methicillin-resistant S. aureus (93.1%). The extract had the lowest effect (30%) on inhibition of B. cereus biofilm formation. impact of the biosurfactant from Halomonas sp. on destruction of the biofilm of E. coli (87.36%) was very significant (P < 0.0001). This synergy of B. persicum extract and Halomonas-drived biosurfactant against E. coli and A. baumannii was more effective than the ciprofloxacin antibiotic. Conclusion: Furthermore, both the extract from B. persicum seeds and the biosurfactant from Halomonas sp. strain individually and synergistically, had a statistically significant effect on the destruction of biofilm produced by methicillin-resistant S. aureus, E. coli, B. cereus and A. baumannii.