Phytochemical Composition and Anti-Efflux Pump Activity of Hydroalcoholic, Aqueous, and Hexane Extracts of Artemisia tournefortiana in Ciprofloxacin-Resistant Strains of Salmonella enterica Serotype Enteritidis

The AcrB efflux pump in Salmonella species plays a significant role in the development of antibiotic resistance in ciprofloxacin-resistant Salmonella enteritidis. This study aimed to investigate the anti-efflux pump activity of Artemisia tournefortiana extracts among S. Enteritidis strains.

The hydroalcoholic, aqueous, and hexanolic extracts of A. tournefortiana were prepared and phytochemical composition of extract was determined using gas chromatography/mass spectrometry (GC/MS) method. After antibiogram, the AcrB efflux pump was detected in ciprofloxacin intermediate and resistant S. enteritidis strains using cartwheel and Polymerase chain reaction (PCR) methods. Finally, minimum inhibitory concentrations (MIC) of extracts against S. enteritidis strains were evaluated. After treatment of S. enteritidis strains with sub-MIC concentrations of extracts, the expression level of AcrB efflux pump gene was evaluated using Real-Time PCR.

Phytochemical analysis of extracts using GC/MS method showed that hexadecanoic acid, ethyl ester (30.7%), and cyclopropane,1-(1-hydroxy-1-heptyl)-2-methylene-3-pentyl (17.8%) were the most dominant volatile components volatile compounds in the extract. The results of antibiogram, cartwheel and PCR methods showed that among 20 strains of S. enteritidis that were resistant and intermediate to ciprofloxacin, 16 strains had AcrB efflux pumps. Finally, Real-Time PCR results showed a significant down-regulation of acrB gene in S. enteritidis strains.

A. tournefortiana had anti-efflux activity and this plant can potentially be used as a natural efflux inhibitor for S. enteritidis strains.