Related Experiment Video
Updated: Jul 20, 2025

Applying an Inducible Expression System to Study Interference of Bacterial Virulence Factors with Intracellular Signaling
Published on: June 25, 2015
Autoinducers modulation as a potential anti-virulence target of bacteria by phenolic compounds
Bryan Moreno-Chamba1, Julio Salazar-Bermeo1, Pablo Navarro-Simarro2
1Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández de Elche (UMH), Alicante, Spain; Instituto de Ingeniería de Alimentos para el Desarrollo, Universitat Politècnica de València, Valencia, Spain.
Objective:
The goal of this study was to determine the effects of phenolic extracts from grape (GrPE), pomegranate (PoPE), and persimmon (PePE) by-products on bacterial virulence activities such as biofilms, motility, energy-dependent efflux pumps, and β-lactamase activity, which are modulated primarily by quorum sensing (QS), defining their potential applications.
Method:
The microdilution method was used to determine the minimum inhibitory concentration (MIC) and sub-inhibitory concentrations (SICs) of the extracts against reference pathogenic bacteria. The antibacterial mode of action was determined by labelling bacterial cells in in vivo cell-tracking experiments.
Results:
Antibiograms showed that PoPE inhibited bacteria at lower concentrations, and PePE had a stronger effect against Klebsiella pneumoniae. Both extracts caused significant cell membrane damage (CMD), whereas GrPE did not. At SICs, all extracts showed anti-QS activity, especially PePE, which inhibited violacein and pyocyanin production at 1/128 × MIC. Additionally, QS autoinducers found in Chromobacterium violaceum and Pseudomonas aeruginosa were modulated by the extracts; PePE showed the highest modulation. Antibiofilm assays revealed that GrPE, at MIC and 2 × MIC, acted as a potent antibiofilm agent against biofilms of Pseudomonas putida, Bacillus cereus, and Staphylococcus aureus, which was related to disruption of swarming motility by GrPE. All extracts, especially PoPE, exerted a potent effect against the activation of efflux pumps of P. aeruginosa as well as β-lactamase activity in K. pneumoniae.
Conclusion:
Results suggest that the anti-virulence potential of the extracts may be related to their effect as extracellular autoinducer modulators. This study allowed to define potential applications of these extracts.
More Related Videos
11:50Bacterial Leaf Infiltration Assay for Fine Characterization of Plant Defense Responses using the Arabidopsis thaliana-Pseudomonas syringae Pathosystem
Published on: October 1, 2015
07:47Anti-virulent Disruption of Pathogenic Biofilms using Engineered Quorum-quenching Lactonases
Published on: January 1, 2016
Related Concept Videos
Gene Regulation in Microbial Communities: Quorum Sensing
Bacterial Signaling
Defense Against Bacterial Pathogens
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
Defenses Against Pathogens and Herbivores
Antimicrobial Proteins
Interferons
Interferons (IFNs) are proteins produced by lymphocytes, macrophages, and fibroblasts infected with viruses. While IFNs cannot prevent viruses from entering and...
Biological Methods for Microbial Control