Abstract

Klebsiella pneumonia (K. pneumonia) and Staphylococcus aureus (S. aureus) are pathogenic bacteria causing various infectious diseases in humans and animals. Currently, herbal ingredients are widely used as antibacterial agents to combat bacterial infections due to their lower side effects, compared to chemical drugs. One such plant with medicinal promise as an antibacterial agent is the oregano plant (Oregano vulgare). It contains substances, such as tannin, flavonoids, carvacrol, thymol, and saponin. Therefore, the current study was conducted to regularly compare the in vitro antibacterial potential of ethanol extract essential oil oregano (Oregano vulgare) on K. pneumonia and S. aureus. In this research, the diffusion method using discs was employed to observe the inhibition zones, while the dilution tube method was utilized to determine the minimum inhibitory concentration (MIC) of the ethanol extract and essential oil of oregano against the test bacteria. The bacterial treatment group received the test material at concentrations of 100, 50, 25, and 12.5. The obtained data were analyzed descriptively in terms of zone inhibition and MIC values. According to the disc diffusion test, the essential oil of oregano demonstrated greater efficacy as an antibacterial agent against K. pneumoniae at a concentration of 100, resulting in an average inhibition zone of 18 mm. Conversely, for S. aureus, a concentration of 1.5 of the essential oil exhibited higher effectiveness, yielding an average inhibition zone of 30 mm. Based on the MIC values, the essential oil was more effective as an antibacterial for K. pneumonia at a concentration of 0.2 (2 mg/mL), while for S. aureus it was more effective at a concentration of 0.19 (1.9 mg/mL). © The Author(s) 2023. All Rights Reserved.