Antimicrobial synergism and antibiofilm activities of Pelargonium graveolens, Rosemary officinalis, and Mentha piperita essential oils against extreme drug-resistant Acinetobacter baumannii clinical isolates
Date
March 2022Metadata
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Taşkın Kafa AH., Aslan R., Celik C., Hasbek M., Antimicrobial synergism and antibiofilm activities of Pelargonium graveolens, Rosemary officinalis, and Mentha piperita essential oils against extreme drug-resistant Acinetobacter baumannii clinical isolates, Z. Naturforsch., 77(3–4) (2022) 95–104.Abstract
Abstract: Rosemary officinalis L., Pelargonium graveolens
L., and Mentha piperita L., essential oils are used by complementary
medicine specialists simultaneously with
traditional antibiotics for treatment purposes. The chemical
composition of essential oils was analyzed by the gas
chromatography-mass spectrometry method. In vitro antibacterial
and antibiofilm activities of the essential oils were
tested against extreme drug-resistant (XDR) colistinresistant
and colistin susceptible Acinetobacter baumannii
clinical strains. The synergistic activities between essential
oils and colistin antibiotics were investigated by the
checkerboard method. The highest antibacterial effect was
detected in mint essential oil (2.5–5 μl/ml), followed by
pelargonium essential oil (5–20 μl/ml) and rosemary
essential oil (5–20 μl/ml). The combination of rosemary
essential oil or pelargonium essential oil with colistin
showed strong synergistic activity in most of the bacterial
strains tested (fractional inhibitory concentration index
≤ 0.5; synergy). As a result of the combination of mint
essential oil and colistin, an indifferent effect was observed
in only two bacterial strains, and other strains could not be
evaluated. No antagonistic effects were observed in any of
the tested essential oils. As a result of the effectiveness of
the combination, the minimum inhibitory concentration
(MIC) values of colistin in XDR-A. baumannii clinical
isolates decreased 2–32 fold. Additionally, the sub-MIC
concentration of essential oils exhibited an inhibitory effect
(48–90%) against the biofilm layer of tested A. baumannii
strains.