Effect of Essential Oil from Lippia origanoides on the Transcriptional Expression of Genes Related to Quorum Sensing, Biofilm Formation, and Virulence of Escherichia coli and Staphylococcus aureus

Abstract

Microbial infections resistant to conventional antibiotics constitute one of the most important causes of mortality in the world. In some bacterial species, such as Escherichia coli and Staphylococcus aureus pathogens, biofilm formation can favor their antimicrobial resistance. These biofilm-forming bacteria produce a compact and protective matrix, allowing their adherence and colonization to different surfaces, and contributing to resistance, recurrence, and chronicity of the infections. Therefore, different therapeutic alternatives have been investigated to interrupt both cellular communication routes and biofilm formation. Among these, essential oils (EO) from Lippia origanoides thymol-carvacrol II chemotype (LOTC II) plants have demonstrated biological activity against different biofilm-forming pathogenic bacteria. In this work, we determined the effect of LOTC II EO on the expression of genes associated with quorum sensing (QS) communication, biofilm formation, and virulence of E. coli ATCC 25922 and S. aureus ATCC 29213. This EO was found to have high efficacy against biofilm formation, decreasing—by negative regulation—the expression of genes involved in motility (fimH), adherence and cellular aggregation (csgD), and exopolysaccharide production (pgaC) in E. coli. In addition, this effect was also determined in S. aureus where the L. origanoides EO diminished the expression of genes involved in QS communication (agrA), production of exopolysaccharides by PIA/PNG (icaA), synthesis of alpha hemolysin (hla), transcriptional regulators of the production of extracellular toxins (RNA III), QS and biofilm formation transcriptional regulators (sarA) and global regulators of biofilm formation (rbf and aur). Positive regulation was observed on the expression of genes encoding inhibitors of biofilm formation (e.g., sdiA and ariR). These findings suggest that LOTCII EO can affect biological pathways associated with QS communication, biofilm formation, and virulence of E. coli and S. aureus at subinhibitory concentrations and could be a promising candidate as a natural antibacterial alternative to conventional antibiotics.

Baicalin-aluminum alleviates necrotic enteritis in broiler chickens by inhibiting virulence factors expression of Clostridium perfringens

“…Therefore, anti-virulence therapy through blocking virulence factors or virulence-associated processes has been shown to be a new alternative therapeutic strategy for bacterial infection. Numerous studies indicated that some plant-derived bioactive compounds were able to control bacterial infection via targeting virulence factors ( Liu et al., 2020 ; Hou et al., 2023 ; Martínez et al., 2023 ). It is found that tectorigenin, an isoflavone extracted from the rhizome of the Chinese herb Belamcanda chinensis (L.) DC, displayed no observable antibacterial activity against C. perfringens , but it significantly inhibited the gliding motility, biofilm formation and adherence to Caco-2 cells of the bacteria by suppressing type IV pilus-associated genes expression ( Liu et al., 2019 ).…”

“…A number of studies indicated that some plant-derived bioactive compounds were able to control bacterial infection via targeting virulence factors and slow down the rise of resistant strains ( Liu et al., 2020 ; Hou et al., 2023 ; Martínez et al., 2023 ). Baicalin-aluminum is a complex of aluminum and baicalin.…”

Natural Antimicrobial Mixtures Disrupt Attachment and Survival of E. coli and C. jejuni to Non-Organic and Organic Surfaces

“…The expression of the structural components of curli genes, including the csgD gene, was drastically reduced in the presence of caffeine, starting from the lowest concentration of 20 mM. The essential oil of Lippia origanoides thymol-Carvacrol II chemotype also demonstrated biological activity against E. coli ATCC 25992 [57]. This essential oil was found to inhibit biofilm formation by downregulating the expression of genes involved in cell aggregation (csgD gene) in E coli.…”

Fighting Microbial Infections from Escherichia coli O157:H7: The Combined Use of Three Essential Oils of the Cymbopogon Genus and a Derivative of Esculentin-1a Peptide

“…Furthermore, the decrease in PGA, obtained by treating the bacteria with the mixtures, caused the instability of the biofilm, with the loss of its architecture. PGA is an essential protein for maintaining the structural integrity of the biofilm, and the downregulation of the pga genes hinders its formation [53,54].…”