Linoleic acid inhibits Pseudomonas aeruginosa biofilm formation by activating diffusible signal factor‐mediated quorum sensing

Abstract

Bacterial biofilm formation causes serious problems in various fields of medical, clinical, and industrial settings. Antibiotics and biocide treatments are typical methods used to remove bacterial biofilms, but biofilms are difficult to remove effectively from surfaces due to their increased resistance. An alternative approach to treatment with antimicrobial agents is using biofilm inhibitors that regulate biofilm development without inhibiting bacterial growth. In the present study, we found that linoleic acid (LA), a plant unsaturated fatty acid, inhibits biofilm formation under static and continuous conditions without inhibiting the growth of Pseudomonas aeruginosa. LA also influenced the bacterial motility, extracellular polymeric substance production, and biofilm dispersion by decreasing the intracellular cyclic diguanylate concentration through increased phosphodiesterase activity. Furthermore, quantitative gene expression analysis demonstrated that LA induced the expression of genes associated with diffusible signaling factor-mediated quorum sensing that can inhibit or induce the dispersion of P. aeruginosa biofilms. These results suggest that LA is functionally and structurally similar to a P. aeruginosa diffusible signaling factor (cis-2-decenoic acid) and, in turn, act as an agonist molecule in biofilm dispersion.

Biological and Physiochemical Methods of Biofilm Adhesion Resistance Control of Medical-Context Surface

“…Even in bacteria such as Escherichia coli and Salmonella that do not produce AHLs (gram negative QS signalling molecule), it still possesses AHL response regulator protein, enabling it to respond to AHLs made by other bacteria. A third QS signalling molecule: Autoinducer-2 (AI-2), has been proposed as the signalling molecule used on an intra-species and inter-species level; facilitating communications between gram positive and negative bacteria [37][38][39]. It is important to note that although QS is essential for the formation of biofilms, the loss of this cell to cell communication system does not cause a lethal effect on bacterial cells [20].…”

Antibacterial Activity and Mechanism of Polygonum orientale L. Essential Oil against Pectobacterium carotovorum subsp. carotovorum

“…It was reported that palmitic acid had in vitro and in vivo efficacy against some bacteria, including Klebsiella pneumoniae , Escherichia coli and so on [ 52 ]. Kim et al [ 53 ] and Kim et al [ 54 ] found that linoleic acid had an inhibitory effect against pathogens such as Staphylococcus aureus , Candida albicans and Pseudomonas aeruginosa , etc. The above results of in vitro antibacterial activity assays ( Table 4 ) and in vivo antibacterial activity assays ( Figure 4 and Figure 5 ) prove that POEO had effective inhibitory activity against Pcc.…”

Identification of FadT as a Novel Quorum Quenching Enzyme for the Degradation of Diffusible Signal Factor in Cupriavidus pinatubonensis Strain HN-2

“…It has been reported that DSF can block protease secretion from attack-phase cells of Bdellovibrio bacteriovorus 109 J completely at the concentration of 50 mM and negatively regulate the membrane integrity at a concentration of 200 mM [75]. Additionally, DSF inhibits biofilm formation with no impacts on the growth of P. aeruginosa under static and continuous conditions [76]. DSF also regulates intercellular public goods (such as extracellular polymeric substances (EPS) and amino acids) [76].…”

“…Additionally, DSF inhibits biofilm formation with no impacts on the growth of P. aeruginosa under static and continuous conditions [76]. DSF also regulates intercellular public goods (such as extracellular polymeric substances (EPS) and amino acids) [76]. DSF-based QS systems are classified into three major classes, the first from Xcc, the second from Burkholderia cenocepacia and Cronobacter turicensis, and the third from Pseudomonas aeruginosa [77][78][79][80].…”