<p>Effect of Sub-Minimum Inhibitory Concentrations of Tyrosol and EDTA on Quorum Sensing and Virulence of <em>Pseudomonas aeruginosa</em></p>

Abstract

Introduction: Pseudomonas aeruginosa is considered a dangerous pathogen, as it causes many human diseases, besides that it is resistant to almost all types of antibacterial agents. So, new strategies to overcome P. aeruginosa infection have evolved to attenuate its virulence factors and inhibit its quorum-sensing (QS) activity. Purpose: This study investigated the effect of tyrosol and EDTA as anti-quorum-sensing and antivirulence agents against P. aeruginosa PAO1. Methods: Anti-quorum activity of sub-minimum inhibitory concentrations (sub-MICs) of tyrosol and EDTA was tested using Chromobacterium violaceum (CV 12,472) biosensor bioassay. Miller assay was used to assess the inhibition of QS signal molecules by βgalactosidase activity determination. Also, their effects on the production of protease, lipase, lecithinase, and motility were tested. The inhibitory effects of these molecules on QS regulatory genes and exotoxins genes expression were evaluated by real-time PCR. Results: Tyrosol and EDTA at sub-MICs inhibited the production of violacein pigment. Both compounds inhibited QS molecules production and their associated virulence factors (protease, lipase, lecithinase, and motility) (P≤ 0.05). Besides, the expression levels of QS regulatory genes (lasI, lasR, rhƖI, rhIR, pqsA, and pqsR) and exotoxins genes (exoS and exoY) were significantly reduced (P≤ 0.05). Conclusion: Both tyrosol and EDTA can be used to fight P. aeruginosa infection as antiquorum-sensing and antivirulence agents at their sub-MICs.

Effect of Alternate Wetting and Drying Irrigation on the Nutritional Qualities of Milled Rice

“…For example, cinnamic acid is induced by beneficial Rhizobia bacteria in rice and is implicated in resistance to Rhizoctonia (Mishra et al, 2006). Another polyphenol called tyrosyl was shown to have very potent antifungal activity not only in plant diseases but also in human infections (Abdel-Rhman et al, 2020;Berne et al, 2020). Sinapinaldehyde or Sinapyl aldehyde is another class of antifungal compound produced naturally in plants.…”

Evaluation of the antibacterial, antibiofilm, and anti-virulence effects of acetic acid and the related mechanisms on colistin-resistant Pseudomonas aeruginosa

“…The effects of AA on the expression levels of P. aeruginosa QS circuit genes (i.e., lasR, rhlR, rhlI, rhlA, and pqsA) and T3SS circuit genes (i.e., exoT, exoS, exsA, and exoY) and the flagellin gene (fliC) were evaluated by qRT-PCR, as described previously [35][36][37][38]. P. aeruginosa TL1671 and TL2314 was incubated in fresh LB broth at 37℃ under 180 rpm until reaching the logarithmic growth phase (OD 600 0.5-0.6).…”

Quorum quenchers affect the virulence regulation of non-mucoid, mucoid and heavily mucoid biofilms co-cultured on cell lines

“…Swimming, swarming and twitching are three forms of motility in P. aeruginosa that are positively controlled by the LasIR and RhIR QS systems; las regulating swimming, swarming and twitching; and rhI controlling swarming and twitching (Yeung et al, 2009 ). Abdel-Rhman et al, ( 2020 ) found that tyrosol (1/4 ×—1/16 × MIC) significantly decreased both swimming and swarming motility, but had no effect on twitching motility. Our study shows that regulation of gene expression differs significantly between strains and in the presence of similar treatments (QQ) (Figs.…”