title: A genomic island defines subspecies-specific virulence features of the host-adapted pathogen Campylobacter fetus subsp. venerealis.
abstract: The pathogen Campylobacter fetus comprises two subspecies, C. fetus subsp. fetus and C. fetus subsp. venerealis. Although these taxa are highly related on the genome level, they are adapted to distinct hosts and tissues. C. fetus subsp. fetus infects a diversity of hosts, including humans, and colonizes the gastrointestinal tract. In contrast, C. fetus subsp. venerealis is largely restricted to the bovine genital tract, causing epidemic abortion in these animals. In light of their close genetic relatedness, the specific niche preferences make the C. fetus subspecies an ideal model system to investigate the molecular basis of host adaptation. In this study, a subtractive-hybridization approach was applied to the genomes of the subspecies to identify different genes potentially underlying this specificity. The comparison revealed a genomic island uniquely present in C. fetus subsp. venerealis that harbors several genes indicative of horizontal transfer and that encodes the core components necessary for bacterial type IV secretion. Macromolecular transporters of this type deliver effector molecules to host cells, thereby contributing to virulence in various pathogens. Mutational inactivation of the putative secretion system confirmed its involvement in the pathogenicity of C. fetus subsp. venerealis.
authors.affiliation: Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, A-8036 Graz, Austria. gregor.gorkiewicz@medunigraz.at
authors.forename: Gregor
authors.initials: G
authors.lastname: Gorkiewicz
authors.forename: Sabine
authors.initials: S
authors.lastname: Kienesberger
authors.forename: Caroline
authors.initials: C
authors.lastname: Schober
authors.forename: Sylvia R
authors.initials: SR
authors.lastname: Scheicher
authors.forename: Christian
authors.initials: C
authors.lastname: Gülly
authors.forename: Rudolf
authors.initials: R
authors.lastname: Zechner
authors.forename: Ellen L
authors.initials: EL
authors.lastname: Zechner
mesh_terms: D054458:Amplified Fragment Length Polymorphism Analysis; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology; D018938:Caco-2 Cells; D002169:Campylobacter Infections / Q000235:genetics; D002168:Campylobacter fetus / Q000235:genetics* / Q000472:pathogenicity*; D016521:Electrophoresis, Gel, Pulsed-Field; D016680:Genome, Bacterial / Q000235:genetics / Q000502:physiology; D044404:Genomic Islands / Q000235:genetics / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014774:Virulence / Q000235:genetics / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins