Antimicrobial Activity of Origanum vulgare Essential Oil against Staphylococcus aureus and Escherichia coli

<b>Background/Objectives</b>: <i>Oreganum vulgare</i> essential oil (OEO) is safe, effective, multifunctional, and widely used. This study aimed to evaluate OEO's chemical composition and antimicrobial activity in vitro against <i>S. aureus</i> and <i>E. coli</i>. <b>Methods</b>: The composition of OEO was determined by gas chromatography-mass spectrometry (GC-MS). <b>Results</b>: Compounds included monoterpenes with known antimicrobial activity, such as 2-menthen-1-ol (36.33%), linalyl acetate (9.26%), terpinene-4-ol (9.01%), 4-thujanol (6.33%), menthen (5.81%), sabinene (5.18%), and carvacrol methyl ether (5.14%). <b>Conclusions</b>: OEO had a strong antimicrobial activity with a minimum inhibitory concentration (MIC) of 1.90 mg/mL for <i>S. aureus</i> and 0.49 mg/mL for <i>E. coli</i> after 18 h incubation. The minimum bactericidal concentration (MBC) was 7.9 mg/mL against <i>S. aureus</i> and 0.99 mg/mL against <i>E. coli</i>. Thus, OEO could be used as a natural antimicrobial against <i>S. aureus</i> and <i>E. coli</i> infections.