ANTIMICROBIAL EFFECTS OF ANTIBIOTICS IN COMBINATION WITH OREGANO ESSENTIAL OIL AGAINST ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIAE

Essential oils from representatives of the family Lamiaceae have proven antimicrobial activity. There is solid scientific evidence for some of them that they have the potential for synergistic interactions with antibiotic agents widely used in clinical practice. The present study aims to investigate...

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Main Authors: Neli Ermenlieva, Sylvia Stamova, Gabriela Tsankova, Gergana Nedelcheva, Krasimira Laleva, Emilia Georgieva
Format: Article
Language:English
Published: Peytchinski Publishing 2025-05-01
Series:Journal of IMAB
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Online Access:https://www.journal-imab-bg.org/issues-2025/issue2/2025vol31-issue2_6118-6223.pdf
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author Neli Ermenlieva
Sylvia Stamova
Gabriela Tsankova
Gergana Nedelcheva
Krasimira Laleva
Emilia Georgieva
author_facet Neli Ermenlieva
Sylvia Stamova
Gabriela Tsankova
Gergana Nedelcheva
Krasimira Laleva
Emilia Georgieva
author_sort Neli Ermenlieva
collection DOAJ
description Essential oils from representatives of the family Lamiaceae have proven antimicrobial activity. There is solid scientific evidence for some of them that they have the potential for synergistic interactions with antibiotic agents widely used in clinical practice. The present study aims to investigate the interaction effects of oregano essential oil (OEO) with some conventional antibiotics against Escherichia coli and Klebsiella pneumoniae tested by agar methods. For this purpose, we selected Escherichia coli ATCC25922, Klebsiella pneumoniae ATCC13883, and four clinical isolates representing these species. OEO in a concentration of 2.5% (v/v) was combined with drugs proposed by EUCAST, 2024 (ampicillin, ceftriaxone, meropenem, gentamicin, ciprofloxacin) and tetracycline. The essential oil was analyzed using gas chromatography coupled with mass spectrometry (GC-MS). The analysis of the Oregano essential oil revealed the main component to be carvacrol (81,20%). The results from our study showed that the combinations of OEO with ceftriaxone and meropenem against Escherichia coli and Klebsiella pneumoniae and the combinations of the OEO with gentamycin and ampicillin against Escherichia coli resulted in an increase in the diameter of the zone of inhibition between 1 and 14 mm. Gentamicin and ciprofloxacin combined with OEO did not increase the zone of inhibition in most of the Klebsiella pneumoniae test samples. While examining the effect of tetracycline combined with OEO, we did not obtain unequivocal results for strengthening the antimicrobial effects against the microbes tested.
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spelling doaj-art-7306d4a7b0bb4f0ca3f74492dcecbb202025-08-20T03:49:21ZengPeytchinski PublishingJournal of IMAB1312-773X2025-05-013126218622310.5272/jimab.2025312.6218ANTIMICROBIAL EFFECTS OF ANTIBIOTICS IN COMBINATION WITH OREGANO ESSENTIAL OIL AGAINST ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIAENeli Ermenlieva0https://orcid.org/0000-0002-4713-5346Sylvia Stamova1https://orcid.org/0000-0003-2135-066XGabriela Tsankova2https://orcid.org/0000-0001-8146-5050Gergana Nedelcheva3https://orcid.org/0000-0003-1295-8884Krasimira Laleva4https://orcid.org/0000-0002-3391-1447Emilia Georgieva5https://orcid.org/0000-0003-2732-6839Department of Microbiology and Virusology, Faculty of Medicine, Medical University-Varna, Bulgaria.Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Medical University - Varna, Bulgaria.Department of Microbiology and Virusology, Faculty of Medicine, Medical University-Varna, Bulgaria.Department of Microbiology and Virusology, Faculty of Medicine, Medical University-Varna, Bulgaria.Department of Social Medicine and Health Care Organization, Faculty of Public Health, Medical University - Varna, Bulgaria.Training sector "Medical laboratory technician", Medical College - Varna, Medical University - Varna, Bulgaria.Essential oils from representatives of the family Lamiaceae have proven antimicrobial activity. There is solid scientific evidence for some of them that they have the potential for synergistic interactions with antibiotic agents widely used in clinical practice. The present study aims to investigate the interaction effects of oregano essential oil (OEO) with some conventional antibiotics against Escherichia coli and Klebsiella pneumoniae tested by agar methods. For this purpose, we selected Escherichia coli ATCC25922, Klebsiella pneumoniae ATCC13883, and four clinical isolates representing these species. OEO in a concentration of 2.5% (v/v) was combined with drugs proposed by EUCAST, 2024 (ampicillin, ceftriaxone, meropenem, gentamicin, ciprofloxacin) and tetracycline. The essential oil was analyzed using gas chromatography coupled with mass spectrometry (GC-MS). The analysis of the Oregano essential oil revealed the main component to be carvacrol (81,20%). The results from our study showed that the combinations of OEO with ceftriaxone and meropenem against Escherichia coli and Klebsiella pneumoniae and the combinations of the OEO with gentamycin and ampicillin against Escherichia coli resulted in an increase in the diameter of the zone of inhibition between 1 and 14 mm. Gentamicin and ciprofloxacin combined with OEO did not increase the zone of inhibition in most of the Klebsiella pneumoniae test samples. While examining the effect of tetracycline combined with OEO, we did not obtain unequivocal results for strengthening the antimicrobial effects against the microbes tested.https://www.journal-imab-bg.org/issues-2025/issue2/2025vol31-issue2_6118-6223.pdfantimicrobial effectsantibioticsoregano essential oilcombination
spellingShingle Neli Ermenlieva
Sylvia Stamova
Gabriela Tsankova
Gergana Nedelcheva
Krasimira Laleva
Emilia Georgieva
ANTIMICROBIAL EFFECTS OF ANTIBIOTICS IN COMBINATION WITH OREGANO ESSENTIAL OIL AGAINST ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIAE
Journal of IMAB
antimicrobial effects
antibiotics
oregano essential oil
combination
title ANTIMICROBIAL EFFECTS OF ANTIBIOTICS IN COMBINATION WITH OREGANO ESSENTIAL OIL AGAINST ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIAE
title_full ANTIMICROBIAL EFFECTS OF ANTIBIOTICS IN COMBINATION WITH OREGANO ESSENTIAL OIL AGAINST ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIAE
title_fullStr ANTIMICROBIAL EFFECTS OF ANTIBIOTICS IN COMBINATION WITH OREGANO ESSENTIAL OIL AGAINST ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIAE
title_full_unstemmed ANTIMICROBIAL EFFECTS OF ANTIBIOTICS IN COMBINATION WITH OREGANO ESSENTIAL OIL AGAINST ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIAE
title_short ANTIMICROBIAL EFFECTS OF ANTIBIOTICS IN COMBINATION WITH OREGANO ESSENTIAL OIL AGAINST ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIAE
title_sort antimicrobial effects of antibiotics in combination with oregano essential oil against escherichia coli and klebsiella pneumoniae
topic antimicrobial effects
antibiotics
oregano essential oil
combination
url https://www.journal-imab-bg.org/issues-2025/issue2/2025vol31-issue2_6118-6223.pdf
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