Antibacterial and antibiofilm activities of some plant essential oils and synergistic effects of cinnamon essential oil with vancomycin against Clostridioides difficile: in vitro study.

The detection of resistant strains of Clostridioides difficile against existing antibiotics and the side effects led to the investigation of alternative agents. Inhibition zones of various essential oils to four strains of C.difficile and other Clostridium species ranged from 8·32 to 44·18 mm. The highest zone was observed in cinnamon and tea tree essential oils. and The MIC values varied between 0·39-25 (%, v/v). The main components were cinnamaldehyde (85·64%) in cinnamon essential oil, 4-terpineol (83·6%) was determined in tea tree essential oil. Additive effects were found between cinnamon essential oil and vancomycin and between cinnamon and tea tree essential oils, and the FICI values were 0·512 and 0·517, respectively. Both cinnamon and tea tree essential oils showed antibiofilm activities against all tested C. difficile strains at all tested concentrations. Essential oils may be used as a supplement in addition to treatment in the control of C. difficile-related diseases.