Mode of Action: Synergistic Interaction of Peppermint (Mentha x piperita L. Carl) Essential Oil and Meropenem Against Plasmid-Mediated Resistant E. coli

Abstract

This study investigated the bactericidal mechanism of peppermint essential oil (PEO) when used singly and in combination with meropenem against multidrug resistant Escherichia coli. Chemical compositions of PEO were identified via GC-MS, followed by time-kill analysis which was performed to evaluate the antibacterial activities of PEO and meropenem. Furthermore, outer membrane permeability test, zeta potential measurement and scanning electron microscopy were performed to evaluate the ability of PEO in bacterial membrane disruption. Next, anti-quorum sensing assay was performed to assess the ability of PEO in quorum sensing inhibition. A complete killing activity was observed within five minutes of treatment with PEO and meropenem at sub-lethal concentrations. In addition, the outer membrane permeability test and zeta potential measurement performed indicated increase in the membrane permeability and membrane disruption which can be observed in the scanning electron micrograph. Furthermore, significant decrease in the light production of E. coli pSB1075 treated by PEO indicates the presence of quorum sensing inhibitors within PEO. The findings suggest that PEO has the ability to disrupt the bacterial outer membrane which increases membrane permeability, in addition to the possible inhibition of bacterial quorum sensing ability in multidrug resistant E. coli, aiding in the reversal of antibiotic resistance.

Lavender essential oil induces oxidative stress which modifies the bacterial membrane permeability of carbapenemase producing Klebsiella pneumoniae

“…Essential oils disrupt bacterial membranes in this and in previous studies 15,33 . The exact mechanism of how bacterial membrane disruption occurs during exposure to essential oil has yet to be elucidated.…”

Antibacterial Activity and Mode of Action of β-caryophyllene on Bacillus cereus

“…The zeta potential value provides information about the membrane potential, which can be related to the metabolic state of bacteria whereby at higher growth rates, zeta potential values are more negative (Yang et al 2018). The alteration in the zeta potential value, becoming less negative, together with the increased surface permeability eventually leads to decreased cell viability (Yang et al 2017).…”

“…This assay was performed to determine the minimum inhibitory concentration (MIC) of BCP against B. cereus via the broth microdilution method. This assay was carried out according to Yang et al (2018) with slight modification. Tween 80 with the final concentration of 10% was incorporated into MHB to enhance the solubility of BCP.…”

“…The cells treated were washed with saline solution for at least three times and resuspended in the fresh saline solution for the zeta potential measurement. These experiments were carried out in triplicate according to Yang et al (2018). Measurement of UV-absorbing materials.…”

“…Currently, natural products such as essential oils (EOs) obtained from plant or animal sources as well as those produced by microorganisms are being studied extensively for their application as alternative antibacterial agents (Yap et al 2017;Yang et al 2018;Yang et al 2019). EOs can be obtained from various plant parts such as flowers, seeds, buds, leaves, and bark.…”