SP1 and infectious meningitis: Although Sp1 genetic background is known to be quite stable as compared to other serotypes [13], our data illustrated that genetic modifications occurred over time inside the Sp1 pool circulating in the African meningitis belt, leading to a switch of the predominant MLVA CC causing CNS infection between two main study periods (2002–2005 and 2004–2007), as previously suggested on a smaller series [29].