Origanum vulgare L. essential oil effects on microbial pathogens causing vaginitis

Multidrug resistance of human isolates of bacteria that cause vaginal infections is one of most recent topics in scientific investigations along with the search for novel antimicrobial drugs originating from nature. Monitoring of antimicrobial activity of traditionally used herbal essential oils may give us basic perspective and directions for future studies design. Antimicrobial activity of commercial essential oil (EO) of Origanum vulgare against human clinical isolates of bacteria and Candida was determined by microdilution method, obtaining minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) (CLSI protocol). Both investigated strains of Candida as well as all bacterial strains, except P. aeruginosa, showed susceptibility to investigated EO. The most susceptible strain was Gram positive S. aureus1 strain unlike S. aureus2 which indicates strain specificity. Both Gram negative E. coli isolates (E. coli1 and E. coli2) showed resistance to all tested antibiotics in this study, and susceptibility to oregano EO at 12.5 ?l/ml. GC/MS analysis identified a total of 35 components (96.13%) in commercial oregano EO, with the most dominant phenol carvacrol (64.12%). Our data suggest that oregano EO possess potent antimicrobial activity and that human vaginal isolates shows strain specificity in antimicrobial susceptibility.