Genomic analysis of the evolution and global spread of hyper-invasive meningococcal lineage 5.

Journal article

Background: The predominant model for bacterial pandemics is the emergence of a virulent variant that diversifies as it spreads in human populations. We investigated a 40-year meningococcal disease pandemic caused by the hyper-invasive ET-5/ST-32 complex.

Methods: A global collection of Neisseria meningitidis isolates dating from 1969 to 2008 was whole genome sequenced (WGS) and analysed using a gene-by-gene approach at http://pubmlst.org/neisseria.

Findings: Analysis of WGS data identified a ‘Lineage 5 pan genome’ of 1940 genes, 1752 (92%) of which were present in all isolates (Lineage 5 ‘core genome’). Genetic diversity, which was mostly generated by horizontal gene transfer, was unevenly distributed in the genome; however, genealogical analysis of diverse and conserved core genes, accessory genes, and antigen encoding genes, robustly identified a star phylogeny with a number of sub-lineages. Most European and American isolates belonged to one of two closely related sub-lineages, which had diversified before the identification of the pandemic in the 1970s. A third, genetically more diverse sub-lineage, was associated with Asian isolates. Several isolates had acquired DNA from the related gonococcus.

Interpretation: These data were inconsistent with a single point of origin followed by pandemic spread, rather suggesting that the sub-lineages had diversified and spread by asymptomatic transmission, with multiple distinct strains causing localised hyperendemic outbreaks.

Authors: Harrison, O; Bray, J; Maiden, M; Caugant, D

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: EBioMedicine
• Volume: 2
• Issue: 3
• Pages: 234-243
• Publication date: 2015-01-13
• Acceptance date: 2015-01-12
• DOI: 10.1016/j.ebiom.2015.01.004
• EISSN: 2352-3964
• ISSN: 2352-3964
• Language: English
• Keywords: serogroup B; genome sequencing; Neisseria meningitidis; evolution