Synergistic effects of Cinnamomum cassia L. essential oil in combination with polymyxin B against carbapenemase-producing Klebsiella pneumoniae and Serratia marcescens

Abstract

Multidrug resistance prompts the search for new sources of antibiotics with new targets at bacteria cell. To investigate the antibacterial activity of Cinnamomum cassia L. essential oil (CCeo) alone and in combination with antibiotics against carbapenemase-producing Klebsiella pneumoniae and Serratia marcescens. The antimicrobial susceptibility of the strains was determined by Vitek ® 2 and confirmed by MALDI-TOF/TOF. The antibacterial activity of CCeo and its synergism with antibiotics was determined using agar disk diffusion, broth microdilution, time-kill, and checkboard methods. The integrity of the bacterial cell membrane in S. marcescens was monitored by protein leakage assay. CCeo exhibited inhibitory effects with MIC = 281.25 μg.mL-1. The association between CCeo and polymyxin B showed a decrease in terms of viable cell counts on survival curves over time after a 4 hour-treatment with a FIC index value of 0.006. Protein leakage was observed with increasing concentrations for CCeo and CCeo + polymyxin B treatments. CCeo showed antibacterial activity against the studied strains. When associated with polymyxin B, a synergistic effect was able to inhibit bacterial growth rapidly and consistently, making it a potential candidate for the development of an alternative treatment and drug delivery system for carbapenemase-producing strains.

Essential Oils: A Natural Weapon against Antibiotic-Resistant Bacteria Responsible for Nosocomial Infections

“…When EOs and antibiotics were tested in combination against antibiotic-resistant bacteria, a significant reduction in concentrations of the antibiotics was observed in many cases, with values much lower than the breakpoint set for that species, and these results were consistent with those of other authors [ 41 , 42 , 43 , 44 ]. The reason for the numerous synergistic effects that emerged both in the present study and in other investigations could be linked to the mechanism of action of EOs, in particular their ability to interact with the permeability of the bacterial cell in Gram-negative bacteria and their capability to alter the gene regulation involved in the cell wall metabolism in Gram-positive bacteria [ 45 ].…”

In vitro and in vivo antibacterial activity assays of carvacrol: A candidate for development of innovative treatments against KPC-producing Klebsiella pneumoniae

“…Optical density was measured at 600 nm on the following day, and the cultures were then diluted to ∼5.0 × 10 5 CFU/mL in a low-binding 96 well microtiter plate containing increasing concentrations of carvacrol (72–0.03 mg/mL). The microtiter plates were incubated at 37°C and the Minimum Inhibitory Concentrations (MIC) and Minimum Bactericidal Concentrations (MBC) of carvacrol were determined as previously described [ 20 , 22 ]. Polymyxin B (4 mg/L) and amikacin (16 mg/L) (Sigma-Aldrich) were used as controls for the assays with carbapenemase-producing and polymyxin-resistant K .…”

“…The time-kill kinetics of the carvacrol at 1 × MBC was performed using the broth macrodilution (MH broth) technique following CLSI guidelines [ 20 , 22 ]. Time-kill assays were performed using a final inoculum concentration of approximately 5.0 × 10 5 CFU/mL [ 23 ] incubated at 37°C.…”

Progress in Alternative Strategies to Combat Antimicrobial Resistance: Focus on Antibiotics

“…The term ‘essential oil’ was first used by Paracelsus von Hohenheim, a medieval Swiss physician [ 102 ]. EOs include terpenes, aldehydes, phenolic, terpenoids, and other aromatic constituents that have demonstrated antimicrobial activities [ 99 , 100 , 101 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 ]. EOs mainly contribute to the disruption of the bacterial cell membrane and inhibition of the efflux pump responsible for certain AMR in Gram-negative bacteria [ 100 , 105 , 114 , 115 , 116 , 117 ].…”