Quercus infectoria gall extracts reduce quorum sensing-controlled virulence factors production and biofilm formation in Pseudomonas aeruginosa recovered from burn wounds

Akhter Ahmed Ahmed,Fraidoon Abdulqadir Salih

doi:10.1186/s12906-019-2594-5

Akhter Ahmed Ahmed, Fraidoon Abdulqadir Salih

Open Access

https://doi.org/10.1186/s12906-019-2594-5

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Abstract

BackgroundQuercus gall extracts’ ability to kill pathogens in vitro and even removal of chronic drug-resistant infections has been reported by several studies. The current investigation is focused on the action of extracts of Quercus infectoria gall in their sub-inhibitory concentrations on the corresponding bacterial behaviours instead of killing them.MethodsThe effect of gall extracts on the quorum sensing (QS) associated virulence of multiple drug resistant Pseudomonas aeruginosa recovered from burns wounds was studied. The influence of different extracts on the production of bacterial virulence and biofilm, and expression of the genes encoding quorum sensing and exotoxin A were investigated. Quorum sensing is a crucial regulator of virulence and biofilm development in Pseudomonas aeruginosa and other medical related microbes.ResultsExperiments to characterise and quantify Q. infectoria gall extracts impact on the quorum sensing networks of P.aeruginosa revealed that the expression of las, rhl, and exotoxin A (ETA) genes levels including the associated virulence were reduced by the extracts at their subinhibitory concentrations.ConclusionsThe obtained results indicated that extracts of Q. infectoria galls fight infections either by their inhibitory constituents, which vigorously eradicate cells or by disruption of the pathogens quorum sensing system through weakening the virulence and bacterial coordination.

Highlights

Quercus gall extracts’ ability to kill pathogens in vitro and even removal of chronic drug-resistant infections has been reported by several studies
Inhibition of planktonic P. aeruginosa by galls extracts of Q. infectoria and growth analysis The Minimum inhibitory concentration (MIC) of Q. infectoria gall extracts were detected to select the Sub-inhibitory concentration (SIC) to evaluate their influence on the bacterial growth and inhibition of quorum sensing (QS)-regulated behaviours
The MICs and the Minimum bactericidal concentration (MBC) of the extracts against the clinical isolate of P. aeruginosa were determined and the SICs of the extracts with ethyl acetate (Q-1), n-butanol (Q-2), ethanol (Q-3), water (Q-4) used throughout the study (Table 1)

Summary

Introduction

Quercus gall extracts’ ability to kill pathogens in vitro and even removal of chronic drug-resistant infections has been reported by several studies. The current investigation is focused on the action of extracts of Quercus infectoria gall in their sub-inhibitory concentrations on the corresponding bacterial behaviours instead of killing them. As the twenty-first century begins, the excessive and undistinguished use of antimicrobials has led to the occurrence of multiple-drug-resistant (MDR) strains [1]. The fact that infectious diseases caused by MDR strains kill 16 million people every year resulted the necessity for alternative approaches to fight these MDRs [2, 3]. The ordinarily adaptive pathogen P. aeruginosa, a Gram-negative bacterium, causes many nosocomial acquired infections, including infected burns and the genetic disease cystic fibrosis, especially in immunocompromised individuals [9]

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