Determination of antibacterial activity of St. John's Wort (Hypericum perforatum L.) oil, Nigella sativa oil, Clove (Eugenia caryophyllata) oil, Orange Peel (Citrus sinensis) and Garlic (Allium sativa) oil against microorganisms isolated from clinical samples

Objective: The aim of this study is to detect St. John's Wort, Nigella sativa, Clove, Orange Peel and Garlic oil on bacteria isolated from blood culture to determine its antibacterial effect. Methods: One hundered blood samples sent to … Medical Microbiology Laboratory between 1 June 2021 and 1 January 2022 were analyzed with blood culture system. Bacteria isolated from blood culture were passaged into blood agar. Bacterial suspension was prepared from the bacterial colonies at 0.5 Mc Farland turbidity. In order to determine the antibacterial activity of plant extract oils, Minimum Inhibition Concentration and Minimal Bactericidal Concentration values were determined by liquid microdilution method. Also, the zone diameters of the disc diffusion method were measured. Results: The antibacterial effect of plant extract oils was detected on only 10 of the 100 clinical samples included in the study. St. John's Wort oil used in these 10 samples showed the most effective antibacterial effect of 7.81 µg/mL against Staphylococcus haemolyticus and Enterobacter aerogenes. Garlic oil showed the most effective antibacterial effect against Escherichia coli and Staphylococcus haemolyticus at 7.81 µg/mL. Nigella sativa oil showed the most effective antibacterial effect against Staphylococcus haemolyticus at 3.9 µg/mL. Orange Peel oil showed the most effective antibacterial effect against Enterococcus faecalis at 1.95 µg/mL. The minimum inhibition concentration at which the oils were effective on microorganisms was determined by comparing them with standard control strains. Conclusion: More clinical isolates and high-dose studies are needed to determine the effectiveness of plant extract oils. Garlic oil Escherichia coli, Staphylococcus haemolyticus and Enterobacter aerogenes, St. John's wort oil Staphylococcus haemolyticus and Enterobacter aerogenes, Nigella sativa) oil on Staphylococcus haemolyticus has been found to be effective