Inhibition of Quorum Sensing-Controlled Virulence Factors and Biofilm Formation in Pseudomonas aeruginosa by Culture Extract from Novel Bacterial Species of Paenibacillus Using a Rat Model of Chronic Lung Infection.

Saad Musbah Alasil,Rahmat Omar,Mohd Yasim Yusof,Salmah Ismail

doi:10.1155/2015/671562

Abstract

Quorum sensing (QS) is a key regulator of virulence factors and biofilm formation in Gram-negative bacteria such as Pseudomonas aeruginosa. Microorganisms that inhabit soil are of strategic importance in the discovery of compounds with anti-QS properties. The objective of the study was to test the culture extract of a taxonomically novel species of Paenibacillus strain 139SI for its inhibitory effects on the QS-controlled virulence factors and biofilm formation of Pseudomonas aeruginosa both in vitro and in vivo. The Paenibacillus sp. culture extract was used to test its anti-QS effects on the LasA protease, LasB elastase, pyoverdin production, and biofilm formation of P. aeruginosa as well as evaluate its therapeutic effects on lung bacteriology, pathology, hematological profile, and serum antibody responses of experimental animals in a rat model of chronic lung infection. Results showed significant decrease in the activities of QS-controlled LasA protease, LasB elastase pyoverdin, and biofilm formation of P. aeruginosa caused by the culture extract. Moreover, the extract significantly prolonged the survival times of rats and facilitated the clearance of biofilm infections from infected lungs. In conclusion, the antiquorum sensing effects of culture extract from a novel species of Paenibacillus provide new insights to combat biofilm-associated infections.

Highlights

Quorum sensing (QS) is a key regulator of virulence factors and biofilm formation in Gram-negative bacteria such as Pseudomonas aeruginosa [1]
There was a significant decrease in LasA activity compared to that of the control when Pseudomonas aeruginosa test supernatant was grown in the presence of Paenibacillus sp. culture extract at concentrations 1 mg/mL and 4.5 mg/mL
Culture extract derived from a taxonomically novel species of Paenibacillus strain 139SI was tested for its ability to inhibit the QS-controlled virulence factors and biofilm formation of a multidrug resistant isolate of P. aeruginosa in vitro as well as its therapeutic effects in vivo using a rat model of chronic biofilm-associated lung infection

Summary

Introduction

Quorum sensing (QS) is a key regulator of virulence factors and biofilm formation in Gram-negative bacteria such as Pseudomonas aeruginosa [1]. Soil is a major source of bacteria that synthesize a wide range of compounds with versatile biological effects [8, 9]. An example of such microorganisms is the genus Paenibacillus. There are 160 species of Paenibacillus approved and validated according to the bacterial nomenclature list by DSMZ [10] These species produce a wide range of antibiotics [11]. Interest in Paenibacillus spp. as a source of new antimicrobial agents is increasing [12]

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Conclusion