Study of the effect of essential oil of Salvia glutinosa L. on microbial biofilm formation by clinical isolates of Acinetobacter baumannii

Abstract

Acinetobacter baumannii is becoming a serious concern in the treatment of infections that can develop resistance to many antibiotics. This persistence may be explained by its capacity to form biofilms. In our study, the essential oil (EO) of the Salvia glutinosa plant, was obtained through the hydrodistillation method. Antimicrobial and antibiofilm activities of the EO on the 20 multi-drug resistant (MDR) A.baumannii isolates were researched. Broth microdilution methods were applied for the determination of the antimicrobial activity. For the determined antibiofilm activity, the Minimal Biofilm Inhibition Concentration (MBIC) test was implemented with the microtiter plate method. Photometric assay was applied for the identification of the antioxidant capacity and colorimetric assay was used to specify the cytotoxicity of the EO of S. glutinosa on L929 cells. In our study, Minimal Inhibition Concentration (MIC) and Minimal Bactericidal Concentration (MBC) values between 1.25-2.5 µl/mL and 5-10 µl/mL respectively. MBIC value of the EO was found as 0.3-2.5 µl/mL. IC50= = 24.4±0.66 µl/mL was found as the antioxidant capacity of the EO. At 25%, 12.5% and 6.25% EO concentrations, no cytotoxicity appeared for the fibroblast cells in terms of the cytotoxic activities (p>0.05). According to the findings obtained in our study, antibiofilm, antimicrobial and antioxidant activities of the S. glutinosa EO seem remarkable. These findings seem promising for the development of potential phytotherapeutic agents in the treatment of the multi-drug resistance (MDR) A.baumannii infections.