Comparative genomics of Neisseria meningitidis: core genome, islands of horizontal transfer and pathogen-specific genes

• DOI: 10.1099/mic.0.29261-0
• Publication Date: 2006-12-12T08:28:10Z
• Authors: Julie C. Dunning ...; Renata Grifantini; Nikhil Kumar; Yih Ling Tzeng; Derrick Fouts; Elisabetta Frigim...; Monia Draghi; Marzia Monica Giu...; Rino Rappuoli; David S. Stephens; Guido Grandi; Hervé Tettelin

To better understandNeisseria meningitidisgenomes and virulence, microarray comparative genome hybridization (mCGH) data were collected from oneNeisseria cinerea, twoNeisseria lactamica, twoNeisseria gonorrhoeaeand 48Neisseria meningitidisisolates. ForN. meningitidis, these isolates are from diverse clonal complexes, invasive and carriage strains, and all major serogroups. The microarray platform representedN. meningitidisstrains MC58, Z2491 and FAM18, andN. gonorrhoeaeFA1090. By comparing hybridization data to genome sequences, the coreN. meningitidisgenome and insertions/deletions (e.g. capsule locus, type I secretion system) related to pathogenicity were identified, including further characterization of the capsule locus, bioinformatics analysis of a type I secretion system, and identification of some metabolic pathways associated with intracellular survival in pathogens. Hybridization data clustered meningococcal isolates from similar clonal complexes that were distinguished by the differential presence of six distinct islands of horizontal transfer. Several of these islands contained prophage or other mobile elements, including a novel prophage and a transposon carrying portions of a type I secretion system. Acquisition of some genetic islands appears to have occurred in multiple lineages, including transfer betweenN. lactamicaandN. meningitidis. However, island acquisition occurs infrequently, such that the genomic-level relationship is not obscured within clonal complexes. TheN. meningitidisgenome is characterized by the horizontal acquisition of multiple genetic islands; the study of these islands reveals important sets of genes varying between isolates and likely to be related to pathogenicity.