Investigation of Antibacterial and Anti-biofilm Activity of Thymbra spicata Essential Oil on Multidrug- Resistant Pseudomonas aeruginosa Strains

Thymbra spicata has been used traditionally as herbal tea forthe treatment of some diseases such as asthma, bronchitis, respiratory, coughs,and sore throat infection in Anatolia. In the current study, the essential oilof T. spicata (EOTS) wereinvestigated for their antimicrobial, anti-biofilm activity and chemicalcomposition. The chemical composition of Thymbraspicata was analyzed by gas chromatography-mass spectrometry (GC-MS).Antimicrobial and anti-biofilm properties were determined using brothmicrodilution methods. According to the results of the present study, the GC-MSprofile highlights that the mains compounds were found grandisol 21.99%,cadinol 6.45%, lavandulol acetate 4.39%. The antibacterial activity of the EOTSwas evaluated by the micro-dilution method against multidrug resistant Pseudomonas aeruginosa. EOTS producedinhibitory effects against the tested strains. It inhibited 11 clinicalisolates of against P. aeruginosawith Minimum Inhibitory Concentration (MIC) values in the range of 1.56-12.5?l/mL. Minimum Biofilm Inhibitory Concentration (MBIC) value was found to berange of 3.12-25 (?l/mL) while the Minimum Biofilm Eradication Concentration(MBEC) value was found to be 6.25-25 (?l/mL). MIC value of the EOTS was appliedonto the bacterial biofilm formations. It was seen that biofilm metabolism wasreduced by 2.0-51.6 %. The findings of this study show that EOTS hasantibacterial and anti-biofilm activity against P. aeruginosa isolates. Thus, essential oil of T. spicata may be useful a potential source for the treatment ofmultidrug resistant P. aeruginosainfections and biofilms.