The antimicrobial and antibiofilm potential of Citrus aurantium and Artemisia annua essential oils nanoemulsions against standard and multidrug-resistant nosocomial pathogens

Antimicrobial resistance has posed considerable health and economic burdens globally (approximately five million deaths annually), particularly among developing countries. The estimated annual treatment costs in the United States include US۴.۶ billion. Vast antibiotic resistance among Gram-negative and Gram-positive bacterial species has spread from healthcare to the environment, community, and animals. These conditions have limited and sometimes failed the infection eradication choices and facilitated the distribution of drug-resistant organisms. The spread of drug-resistant bacterial infections is a huge human health concern, hence seeking novel antibacterial agents is crucial. This study used the nanoemulsions of Citrus aurantium and Artemisia annua essential oils (EOs) as natural antibacterial agents. GC–MS analysis showed that limonene (۳۱.۴%) and artemisia ketone (۲۶.۲%) were major components, respectively. After that, their nanoemulsion dosage forms with a mean droplet size of ۱۸۱ ± ۷ and ۱۶۰ ± ۵ and with zeta potential values ۳.۱ ± ۰.۸ and -۴.۹ ± ۰.۵ mV were prepared. Meanwhile, successful loading of the EOs in nanoemulsion was confirmed by ATR-FTIR analysis. A. annua nanoemulsion with ۴۰% antioxidant effect was significantly more potent than C. aurantium nanoemulsion. Meanwhile, nanoemulsions' antibacterial and antibiofilm activity against clinical and standard strains, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumonia, were investigated. The best efficiency was related to the effect of C. aurantium nanoemulsion against S. aureus; MIC and MBC were ۵۰۰ and > ۲۰۰۰ µg/mL. Besides, no biofilm was formed after treatment by both nanoemulsions. Therefore, C. aurantium and A. annua EO nanoemulsions may act as natural antioxidant and antibacterial agents in complementary medicine.

Keywords:

Antibacterial Agents , essential oil , Reactive oxygen species , Phytochemicals