Anti-Virulence Properties of Plant Species: Correlation between In Vitro Activity and Efficacy in a Murine Model of Bacterial Infection

Abstract

Several plant extracts exhibit anti-virulence properties due to the interruption of bacterial quorum sensing (QS). However, studies on their effects at the preclinical level are scarce. Here, we used a murine model of abscess/necrosis induced by Pseudomonas aeruginosa to evaluate the anti-pathogenic efficacy of 24 plant extracts at a sub-inhibitory concentration. We analyzed their ability to inhibit QS-regulated virulence factors such as swarming, pyocyanin production, and secretion of the ExoU toxin via the type III secretion system (T3SS). Five of the seven extracts with the best anti-pathogenic activity reduced ExoU secretion, and the extracts of Diphysa americana and Hibiscus sabdariffa were identified as the most active. Therefore, the abscess/necrosis model allows identification of plant extracts that have the capacity to reduce pathogenicity of P. aeruginosa. Furthermore, we evaluated the activity of the plant extracts on Chromobacterium violaceum. T3SS (ΔescU) and QS (ΔcviI) mutant strains were assessed in both the abscess/necrosis and sepsis models. Only the ΔescU strain had lower pathogenicity in the animal models, although no activity of plant extracts was observed. These results demonstrate differences between the anti-virulence activity recorded in vitro and pathogenicity in vivo and between the roles of QS and T3S systems as virulence determinants.

Phenolic Compounds and Antioxidant Activity in Edible Flower Species from Oaxaca

“…The composition and antioxidant activity of D. americana (synonyms: D. robinioides or D. carthagenensis) are related to its high potential to be beneficial to human health. The characteristics of this species are associated with the prevention or treatment of gastrointestinal disorders generated by bacteria [41]; furthermore, the species has antifungal activity for treating dermatophytosis [42] and antivirulence properties that can be applied to agricultural crops [43]. These potential applications are also due to the set of compounds that have been identified in the species as isoflavones [44].…”

Research Progress on Small Molecular Inhibitors of the Type 3 Secretion System

“…Bacterial infections are one of the most common causes of human and animal disease [ 1 , 2 ]. Furthermore, infection by pathogenic plant bacteria can cause significant production losses in food and cash crops [ 3 , 4 , 5 , 6 , 7 ]. Generally, depending on the composition of the cytoderm, pathogens are classified into Gram-negative and Gram-positive bacteria.…”