Eugenol in combination with lactic acid bacteria attenuates Listeria monocytogenes virulence in vitro and in invertebrate model Galleria mellonella

Abstract

Listeria monocytogenes is a human enteric pathogen that causes severe foodborne illness in high-risk populations. Crossing the intestinal barrier is the first critical step for Listeria monocytogenes infection. Therefore, reducing L. monocytogenes colonization and invasion of intestinal epithelium and production of virulence factors could potentially control listeriosis in humans. This study investigated the efficacy of sub-inhibitory concentration (SIC) of the plantderived antimicrobial eugenol, either alone, or in combination with five lactic acid bacteria (LAB), namely Bifidobacterium bifidum (NRRL-B41410), Lactobacillus reuteri (B-14172), Lactobacillus fermentum (B-1840), Lactobacillus plantarum (B-4496) and Lactococcus lactis subspecies lactis (B-633) in reducing Listeria monocytogenes adhesion to and invasion of human intestinal epithelial cells (Caco-2). Additionally, the effect of the aforementioned treatments on Listeria monocytogenes listeriolysin production, epithelial E-cadherin binding and expression of virulence genes was investigated. Moreover, the in vivo efficacy of eugenol-LAB treatments in reducing Listeria monocytogenes virulence in the invertebrate model Galleria mellonella was studied. Eugenol and LAB, either alone or in combination, significantly reduced Listeria monocytogenes adhesion to and invasion of intestinal cells (P < 0.05). Moreover, eugenol-LAB treatments decreased Listeria monocytogenes haemolysin production, E-cadherin binding and virulence gene expression (P < 0.05). In addition, the eugenol-LAB treatments significantly enhanced the survival rates of G. mellonella infected with lethal doses of Listeria monocytogenes (P < 0.05). The results highlight the antilisterial effect of eugenol either alone or in combination with LAB, and justify further investigations in a mammalian model.

Progress on the Antimicrobial Activity Research of Clove Oil and Eugenol in the Food Antisepsis Field

“…The MBC of eugenol to L. monocytogenes was 450 mg/kg (García‐García, López‐Malo, & Palou, ), and both SIC (1.8 mM) and MBC (2.5 mM) of eugenol inhibits the biofilm synthesis and inactivates fully formed biofilms of the bacteria, and these effects are associated with the downregulation of critical biofilm‐associated gene dnaK, bacterial adhesion‐related genes flaA, fliP, flgE, and motA, transcriptional activation gene prfA, and quorum sensing‐related genes (Upadhyay, Upadhyaya, Kollanoor‐Johny, & Venkitanarayanan, ). Otherwise, SIC of eugenol also significantly reduces adhesion and invasion of L. monocytogenes to intestinal cells Caco‐2, decreases E‐cadherin binding, hemolysin production, and virulence gene expression, and enhances the survival rates of G. mellonella model infected with lethal doses of the bacteria (Upadhyay, Upadhyaya, Mooyottu, & Venkitanarayanan, ).…”

Quorum quenching intervened in vivo attenuation and immunological clearance enhancement by Solanum torvum root extract against Pseudomonas aeruginosa instigated pneumonia in Sprague Dawley rats

“…Importantly it has to be highlighted that STRE does not possess any kind of effect upon bacterial growth and biomass but the histological and hematological investigations points out that immune response found in STRE treated group was natural such as inflammation, Ig elevation and PMN infiltration [33,34]. However such in vivo attenuation of bacterial pathogens was previously reported by [35] where in Eugenol in combination with lactic acid bacteria attenuated Listeria monocytogenes virulence in invertebrate model Galleria mellonella. The attenuating activity and thereby immunomodulatory effect of Solanum torvum root extract can be explained due to its high quorum quenching ability.…”

Inhibition strategies of Listeria monocytogenes biofilms—current knowledge and future outlooks

“…Combined treatment inhibit the biofilm formation [178] The encapsulated solution are potent antibacterial and antibiofilm agents [179] Allyl isothiocyanate and 2phenylethylethylisothiocyanate Brassicaceae family Inhibition of motility and microbial growth (>60%) by binding to sulfhydryl groups on bacterial cell active sites leading to reduction of cellular levels of thiol groups and formation of oxygen and free radicals [180] Yarrow essential oil Yarrow (Achillea millefolium) Partial inhibition of cell attachment and preformed biofilm by disruption of cell membrane resulting in extreme cell permeability and cell death [181] Lemon grass essential oil Cymbopogon sp. Biofilm inhibition occurred after 60 min of contact through permeabilization of cell membrane [130] Resveratrol Skin of fruits The natural phytoalexin posses antibiofilm (especially in food models), anti-inflammatory, antioxidant, neuro-protective, and antimicrobial activities [182] Gallic acid and ferulic acid Tea, fruits and edible crops Inactivate the stages of biofilm (attachment and motility) by >70% Reduction of pathogenicity (listerolysin, hemolysis, epithelial E-cadherin binding) and adherence [190] Exopolysaccharide Probiotic Enterococcus faecium MC13 High emulsification, flocculation and biofilm activity of heteropolysaccharide produced at favorable temperature, pH, and salinity [191] (Continues) OLOKETUYI AND KHAN | 733…”