Replacement of Neisseria meningitidis C cc11/ET-15 variant by a cc103 hypervirulent clone, Brazil 2005-2011.

Outbreaks caused by serogroup C meningococci in the northeast region of Brazil from 2005 to 2011 were associated to the emergence of variant ET-15 of cc11, which has been replaced by cc103 from 2006 to date. The increase of cc103 should be closely monitored to prevent the spread of this clone to neighbouring regions.