Characterization of JG024, a pseudomonas aeruginosa PB1-like broad host range phage under simulated infection conditions

Julia Garbe,Manfred Rohde,Andrea Wesche,Johannes Sikorski,Dieter Jahn,Max Schobert,Christine Rohde,Boyke Bunk,Marlon Kazmierczak,Katherina Selezska

doi:10.1186/1471-2180-10-301

Abstract

BackgroundPseudomonas aeruginosa causes lung infections in patients suffering from the genetic disorder Cystic Fibrosis (CF). Once a chronic lung infection is established, P. aeruginosa cannot be eradicated by antibiotic treatment. Phage therapy is an alternative to treat these chronic P. aeruginosa infections. However, little is known about the factors which influence phage infection of P. aeruginosa under infection conditions and suitable broad host range phages.ResultsWe isolated and characterized a phage, named JG024, which infects a broad range of clinical and environmental P. aeruginosa strains. Sequencing of the phage genome revealed that the phage JG024 is highly related to the ubiquitous and conserved PB1-like phages. The receptor of phage JG024 was determined as lipopolysaccharide. We used an artificial sputum medium to study phage infection under conditions similar to a chronic lung infection. Alginate production was identified as a factor reducing phage infectivity.ConclusionsPhage JG024 is a suitable broad host range phage which could be used in phage therapy. Phage infection experiments under simulated chronic lung infection conditions showed that alginate production reduces phage infection efficiency.

Highlights

Pseudomonas aeruginosa causes lung infections in patients suffering from the genetic disorder Cystic Fibrosis (CF)
JG024 is even capable of infecting a P. aeruginosa mucA mutant and the clinical isolate BT73, which both showed the same mucoid phenotype. mucA mutants produce large amounts of the exopolysaccharide alginate and mutations in mucA are critical for the conversion of non-mucoid to mucoid P. aeruginosa variants in the lung of CF patients [20,21]
We determined the host range of the phage JG024 with a collection of 100 P. aeruginosa environmental strains isolated from different rivers (Oker, Aller, Weser) in Lower Saxony, Germany

Summary

Introduction

Pseudomonas aeruginosa causes lung infections in patients suffering from the genetic disorder Cystic Fibrosis (CF). Once a chronic lung infection is established, P. aeruginosa cannot be eradicated by antibiotic treatment. Respiratory tract infections caused by P. aeruginosa are dreaded in patients suffering from the genetic disorder Cystic Fibrosis (CF) [2,6,7]. Bacteria like P. aeruginosa are able to colonize this mucus and cause chronic infections, which cannot be eradicated by antibiotic treatment [4]. Several hypothesis exist explaining the observed high antibiotic tolerance of P. aeruginosa in the CF-lung, which is caused by special growth conditions. These include growth as biofilm-like microcolonies, which have been shown to increase and the genome sizes vary between 64,427 and 66,530 bp. We used an artificial sputum medium to simulate the conditions in the CF lung and investigated the ability of phage JG024 to infect P. aeruginosa and multiply under these conditions

Methods

Results

Conclusion