Antimicrobial activity and mode of action of terpene linalyl anthranilate against carbapenemase-producing Klebsiella pneumoniae

Abstract

Mining of plant-derived antimicrobials is the major focus at current to counter antibiotic resistance. This study was conducted to characterize the antimicrobial activity and mode of action of linalyl anthranilate (LNA) against carbapenemase-producing Klebsiella pneumoniae (KPC-KP). LNA alone exhibited bactericidal activity at 2.5% ( V/V ), and in combination with meropenem (MPM) at 1.25% ( V/V ). Comparative proteomic analysis showed a significant reduction in the number of cytoplasmic and membrane proteins, indicating membrane damage in LNA-treated KPC-KP cells. Up-regulation of oxidative stress regulator proteins and down-regulation of oxidative stress-sensitive proteins indicated oxidative stress. Zeta potential measurement and outer membrane permeability assay revealed that LNA increases both bacterial surface charge and membrane permeability. Ethidium bromide influx/efflux assay showed increased uptake of ethidium bromide in LNA-treated cells, inferring membrane damage. Furthermore, intracellular leakage of nucleic acid and proteins was detected upon LNA treatment. Scanning and transmission electron microscopies again revealed the breakage of bacterial membrane and loss of intracellular materials. LNA was found to induce oxidative stress by generating reactive oxygen species (ROS) that initiate lipid peroxidation and damage the bacterial membrane. In conclusion, LNA generates ROS, initiates lipid peroxidation, and damages the bacterial membrane, resulting in intracellular leakage and eventually killing the KPC-KP cells.

Chemical Composition and Biological Activities of the Essential Oils of Chrysophyllum albidum G. Don (African Star Apple)

“…These ROS could initiate lipid oxidation via a membrane lipid attack and could thus disrupt bacterial cell membrane and hence leak intracellular contents. The ROS could also leak into intracellular regions and degrade nucleic acids, lipids, and/or proteins [ 34 ]. The presence of sesquiterpenes may also contribute to the antimicrobial activity of essential oils.…”

Antibacterial Effect of Oregano Essential Oil against Vibrio vulnificus and Its Mechanism

“…In this study, the increase to the intracellular MDA content of V. vulnificus treated with OEO was consistent with the increased trend of ROS (Figure 6). Similarly, Yang et al [47] found that the quantitative MDA level of Carbapenemase-producing Klebsiella pneumoniae treated by linalyl anthranilate was significantly higher than those of untreated cells, and this trend was also found in the change of the ROS level. Moreover, Ajiboye et al [49] considered that the increase of MDA in catechin treated E. coli, Pseudomonas aeruginosa and Staphylococcus aureus indicates that the cells are attacked by macromolecules, which may have been due to lipid peroxidation caused by enhanced production of reactive oxygen species.…”

“…Similarly, Li et al [46] found that epigallocatechin gallate, the main polyphenol component in tea, killed V. mimicus by increasing the production of intracellular ROS. Likewise, limonene can induce a large number of hydroxyl radicals, thereby improving the level of ROS in Penicillium digitatum spores [47]. Vatansever et al [44] believe that excessive ROS will destroy the defense systems of superoxide dismutase (SOD) and catalase (CAT) in bacteria.…”

Combination Therapy Involving Lavandula angustifolia and Its Derivatives in Exhibiting Antimicrobial Properties and Combatting Antimicrobial Resistance: Current Challenges and Future Prospects

“…This is probably the first huge-scaled study focusing on the beneficial effects of LEO when used in combination with other antimicrobial agents [114]. Another study conducted by Yang et al (2020) detected the presence of synergistic antimicrobial effects when LEOs are used concurrently with meropenem against carbapenemase-producing K. pneumoniae, where MIC values of both LEO and meropenem were found to be remarkably decreased. Checkerboard and time-kill assays revealed the FICI to be 0.31 and further proteomic analysis revealed the combination of LEO and meropenem causes disruption of the cellular membrane of K. pneumoniae via induction of oxidative stress, resulting in influx of LEO-meropenem and other generated free radicals into the bacterial cell [115].…”