[Meningococci infection by a bacteriophage with a virulence factor].

Meningococci are bacteria dreaded for their ability to kill young people. However, meningococci and humans usually live together peacefully. In a minority of cases, the co-existence results in disease. Recently, whole genome comparisons between hyperinvasive clones and clones not associated with disease revealed that a chromosomally integrated bacteriophage was related to invasiveness. Many examples of bacteriophage-encoded virulence factors are known--as such, this finding is not remarkable. However, the way this virulence factor was found is a nice example of unravelling the pathogenesis of infectious diseases in the genomic era.