title: Closely related Campylobacter jejuni strains from different sources reveal a generalist rather than a specialist lifestyle.
abstract: BACKGROUND
  Campylobacter jejuni and Campylobacter coli are human intestinal pathogens of global importance. Zoonotic transmission from livestock animals or animal-derived food is the likely cause for most of these infections. However, little is known about their general and host-specific mechanisms of colonization, or virulence and pathogenicity factors. In certain hosts, Campylobacter species colonize persistently and do not cause disease, while they cause acute intestinal disease in humans.
  
  
  RESULTS
  Here, we investigate putative host-specificity using phenotypic characterization and genome-wide analysis of genetically closely related C. jejuni strains from different sources. A collection of 473 fresh Campylobacter isolates from Germany was assembled between 2006 and 2010 and characterized using MLST. A subset of closely related C. jejuni strains of the highly prevalent sequence type ST-21 was selected from different hosts and isolation sources. PCR typing of strain-variable genes provided evidence that some genes differed between these strains. Furthermore, phenotypic variation of these strains was tested using the following criteria: metabolic variation, protein expression patterns, and eukaryotic cell interaction. The results demonstrated remarkable phenotypic diversity within the ST-21 group, which however did not correlate with isolation source. Whole genome sequencing was performed for five ST-21 strains from chicken, human, bovine, and food sources, in order to gain insight into ST-21 genome diversity. The comparisons showed extensive genomic diversity, primarily due to recombination and gain of phage-related genes. By contrast, no genomic features associated with isolation source or host were identified.
  
  
  CONCLUSIONS
  The genome information and phenotypic data obtained in vitro and in a chicken infection model provided little evidence of fixed adaptation to a specific host. Instead, the dominant C. jejuni ST-21 appeared to be characterized by phenotypic flexibility and high genetic microdiversity, revealing properties of a generalist. High genetic flexibility might allow generalist variants of C. jejuni to reversibly express diverse fitness factors in changing environments.
authors: Institute for Medical Microbiology, Hannover Medical School, Hannover, Germany.
authors: Eugenia
authors: E
authors: Gripp
authors: Daniela
authors: D
authors: Hlahla
authors: Xavier
authors: X
authors: Didelot
authors: Friederike
authors: F
authors: Kops
authors: Sven
authors: S
authors: Maurischat
authors: Karsten
authors: K
authors: Tedin
authors: Thomas
authors: T
authors: Alter
authors: Lüppo
authors: L
authors: Ellerbroek
authors: Kerstin
authors: K
authors: Schreiber
authors: Dietmar
authors: D
authors: Schomburg
authors: Traute
authors: T
authors: Janssen
authors: Patrick
authors: P
authors: Bartholomäus
authors: Dirk
authors: D
authors: Hofreuter
authors: Sabrina
authors: S
authors: Woltemate
authors: Markus
authors: M
authors: Uhr
authors: Birgit
authors: B
authors: Brenneke
authors: Petra
authors: P
authors: Grüning
authors: Gerald
authors: G
authors: Gerlach
authors: Lothar
authors: L
authors: Wieler
authors: Sebastian
authors: S
authors: Suerbaum
authors: Christine
authors: C
authors: Josenhans
mesh_terms: D000818:Animals; D016123:Campylobacter jejuni / Q000145:classification / Q000302:isolation & purification* / Q000502:physiology; D005516:Food Microbiology; D006801:Humans; D010802:Phylogeny; D013045:Species Specificity