Host adaption to the bacteriophage carrier state of Campylobacter jejuni

Kelly J Brathwaite,Patcharin Siringan,Phillippa L Connerton,Ian F Connerton

doi:10.1016/j.resmic.2015.05.003

Kelly J Brathwaite, Patcharin Siringan + Show 2 more

Open Access

https://doi.org/10.1016/j.resmic.2015.05.003

Copy DOI

Abstract

The carrier state of the foodborne pathogen Campylobacter jejuni represents an alternative life cycle whereby virulent bacteriophages can persist in association with host bacteria without commitment to lysogeny. Host bacteria exhibit significant phenotypic changes that improve their ability to survive extra-intestinal environments, but exhibit growth-phase-dependent impairment in motility. We demonstrate that early exponential phase cultures become synchronised with respect to the non-motile phenotype, which corresponds with a reduction in their ability to adhere to and invade intestinal epithelial cells. Comparative transcriptome analyses (RNA-seq) identify changes in gene expression that account for the observed phenotypes: downregulation of stress response genes hrcA, hspR and per and downregulation of the major flagellin flaA with the chemotactic response signalling genes cheV, cheA and cheW. These changes present mechanisms by which the host and bacteriophage can remain associated without lysis, and the cultures survive extra-intestinal transit. These data provide a basis for understanding a critical link in the ecology of the Campylobacter bacteriophage.

Highlights

The bacterial pathogen Campylobacter jejuni is a common cause of human diarrhoeal disease worldwide
Motile bacteria appeared at 6 h, followed by a rise in the phage titres, presumably because these bacteria can be infected by bacteriophage and lysed
We previously demonstrated that Campylobacter bacteriophages can enter into a complex relationship with their host

Summary

Introduction

The bacterial pathogen Campylobacter jejuni is a common cause of human diarrhoeal disease worldwide. Bacteriophages have the potential to control bacterial pathogens, and the application of bacteriophages that predate campylobacters can reduce the intestinal carriage of poultry [2,3] and the contamination of poultry meat [4]. Campylobacter-specific bacteriophages can be recovered from the intestines of poultry where their host bacteria proliferate [5], and readily infect and replicate within campylobacters in the laboratory [6]. Under these circumstances the bacteriophages are exclusively virulent in that they propagate by infection and lysis of host bacteria. A new subfamily, the Eucampyvirinae, has been proposed that consists of two genera: “Cp220likevirus” and ‘‘Cp8unalikevirus”, which characteristically possess genome sizes in the range of 130e140 and 170e190 kb respectively [7]

Objectives

Methods

Results

Conclusion