A multi-host approach to identify a transposon mutant of Pseudomonas aeruginosa LESB58 lacking full virulence

Cynthia Gagné-Thivierge,Valérie Dekimpe,Éric Déziel,Sok Gheck E Tan,Antony T Vincent,Roger C Levesque,Geneviève Filion,Steve J Charette,Irena Kukavica-Ibrulj

doi:10.1186/s13104-018-3308-7

Abstract

ObjectivePseudomonas aeruginosa is an opportunistic bacterial pathogen well known to cause chronic lung infections in individuals with cystic fibrosis (CF). Some strains adapted to this particular niche show distinct phenotypes, such as biofilm hyperproduction. It is necessary to study CF clinical P. aeruginosa isolates, such as Liverpool Epidemic Strains (LES), to acquire a better understanding of the key genes essential for in vivo maintenance and the major virulence mechanisms involved in CF lung infections. Previously, a library of 9216 mutants of the LESB58 strain were generated by signature-tagged mutagenesis (STM) and screened in the rat model of chronic lung infection, allowing the identification of 163 STM mutants showing defects in in vivo maintenance.ResultsIn the present study, these 163 mutants were successively screened in two additional surrogate host models (the amoeba and the fruit fly). The STM PALES_11731 mutant was the unique non-virulent in the three hosts. A competitive index study in rat lungs confirmed that the mutant was 20-fold less virulent than the wild-type strain. This study demonstrated the pertinence to use a multi-host approach to study the genetic determinants of P. aeruginosa strains infecting CF patients.

Highlights

Pseudomonas aeruginosa is one of the most common pathogenic bacteria causing lung infections among cystic fibrosis (CF) patients [1]
This study demonstrated the pertinence to use a multi-host approach to study the genetic determinants of P. aeruginosa strains infecting CF patients
The Liverpool Epidemic Strain (LES) B58 (LESB58) is one of those strains found in chronic CF lung infections and one of the first P. aeruginosa strains identified as epidemic among CF patients [4]

Summary

Results

These 163 mutants were successively screened in two additional surrogate host models (the amoeba and the fruit fly). The STM PALES_11731 mutant was the unique non-virulent in the three hosts. A com‐ petitive index study in rat lungs confirmed that the mutant was 20-fold less virulent than the wild-type strain. This study demonstrated the pertinence to use a multi-host approach to study the genetic determinants of P. aeruginosa strains infecting CF patients

Introduction

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Results and discussion

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