title: Whole-genome comparison of disease and carriage strains provides insights into virulence evolution in Neisseria meningitidis.
abstract: Neisseria meningitidis is a leading cause of infectious childhood mortality worldwide. Most research efforts have hitherto focused on disease isolates belonging to only a few hypervirulent clonal lineages. However, up to 10% of the healthy human population is temporarily colonized by genetically diverse strains mostly with little or no pathogenic potential. Currently, little is known about the biology of carriage strains and their evolutionary relationship with disease isolates. The expression of a polysaccharide capsule is the only trait that has been convincingly linked to the pathogenic potential of N. meningitidis. To gain insight into the evolution of virulence traits in this species, whole-genome sequences of three meningococcal carriage isolates were obtained. Gene content comparisons with the available genome sequences from three disease isolates indicate that there is no core pathogenome in N. meningitidis. A comparison of the chromosome structure suggests that a filamentous prophage has mediated large chromosomal rearrangements and the translocation of some candidate virulence genes. Interspecific comparison of the available Neisseria genome sequences and dot blot hybridizations further indicate that the insertion sequence IS1655 is restricted only to N. meningitidis; its low sequence diversity is an indicator of an evolutionarily recent population bottleneck. A genome-based phylogenetic reconstruction provides evidence that N. meningitidis has emerged as an unencapsulated human commensal from a common ancestor with Neisseria gonorrhoeae and Neisseria lactamica and consecutively acquired the genes responsible for capsule synthesis via horizontal gene transfer.
authors.affiliation: Institute for Hygiene and Microbiology, University of Würzburg, Josef-Schneider-Strasse 2, 97080 Würzburg, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schoen
authors.forename: Jochen
authors.initials: J
authors.lastname: Blom
authors.forename: Heike
authors.initials: H
authors.lastname: Claus
authors.forename: Anja
authors.initials: A
authors.lastname: Schramm-Glück
authors.forename: Petra
authors.initials: P
authors.lastname: Brandt
authors.forename: Tobias
authors.initials: T
authors.lastname: Müller
authors.forename: Alexander
authors.initials: A
authors.lastname: Goesmann
authors.forename: Biju
authors.initials: B
authors.lastname: Joseph
authors.forename: Sebastian
authors.initials: S
authors.lastname: Konietzny
authors.forename: Oliver
authors.initials: O
authors.lastname: Kurzai
authors.forename: Corinna
authors.initials: C
authors.lastname: Schmitt
authors.forename: Torben
authors.initials: T
authors.lastname: Friedrich
authors.forename: Burkhard
authors.initials: B
authors.lastname: Linke
authors.forename: Ulrich
authors.initials: U
authors.lastname: Vogel
authors.forename: Matthias
authors.initials: M
authors.lastname: Frosch
mesh_terms: D001483:Base Sequence; D005075:Biological Evolution; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D006801:Humans; D008589:Meningococcal Infections; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000235:genetics* / Q000472:pathogenicity*; D010802:Phylogeny; D014774:Virulence / Q000235:genetics