The Antibacterial Activity of Satureja khuzestanica Essential Oil Against Clinical Isolates of E. coli

Background: In folk medicine, Satureja khuzestanica infusion is prescribed to use before the meals to treat muscle pains, indigestion, cramps, nausea, diarrhea, and infectious diseases, especially bladder infections and inflammations. Objectives: This study aimed to evaluate the antibacterial activity of S. khuzestanica essential oil against clinical isolates of E. coli from urinary tract infections. Materials and Methods: The chemical composition of S. khuzestanica essential oil was determined by gas chromatography (GC) and mass spectrometer (GC-MS) analyses. The antibacterial activity of S. khuzestanica essential oil and carvacrol as its main component was evaluated by disk diffusion and microbroth dilution assays. Then, the synergistic activity of essential oil and carvacrol with gentamicin were determined by checkerboard microtiter assay. Results: The chemical analysis of S. khuzestanica essential oil revealed the presence of carvacrol (94.1%) as its main component. The inhibition zone diameters of S. khuzestanica essential oil and carvacrol dose-dependently increased. The Minimum Inhibitory Concentration (MIC) values of S. khuzestanica essential oil and carvacrol were 0.14 ± 0.08 µL/mL and 0.09 ± 0.04 µL/mL, respectively. S. khuzestanica essential oil and carvacrol showed bactericidal effects against clinical isolates of E. coli and synergistic effect with gentamicin (fractional inhibitory concentration index < 0.05). Conclusions: The antibacterial activity of S. khuzestanica essential oil is associated with carvacrol as its main component. The presence of other minor components in essential oil decreases the antibacterial activity of S. khuzestanica essential oil. Other clinical studies are essential to demonstrate the antibacterial effects of S. khuzestanica for treatment of urinary tract infection.