Microevolution and virulence in an outbreak of clonal complex 11 Neisseria meningitidis from Western Australia

Neisseria meningitidis (Nme) is the cause of invasive meningococcal disease (IMD). This thesis details an outbreak of hyperinvasive clonal complex 11 Nme from Western Australia, including the carriage of Nme in remote communities and microevolution of the cc11 lineage during the outbreak. This work identifies genetic changes associated with capsule switching during the outbreak and shows that recombination within the lineage and a novel lipooligosaccharide hypersialylation phenotype impacted invasiveness. This work supports the hypothesis that meningococcal virulence is driven by both metabolic and virulence factors and identifies the potential for meningococcal microevolution in the context of high levels of vaccination.