Microevolution and Its Impact on Hypervirulence, Antimicrobial Resistance, and Vaccine Escape in .

is commensal of the human pharynx and occasionally invades the host, causing the life-threatening illness invasive meningococcal disease. The meningococcus is a highly diverse and adaptable organism thanks to natural competence, a propensity for recombination, and a highly repetitive genome. These mechanisms together result in a high level of antigenic variation to invade diverse human hosts and evade their innate and adaptive immune responses.

The Host-Pathogen Interactions and Epicellular Lifestyle of .

is a gram-negative diplococcus and a transient commensal of the human nasopharynx. It shares and competes for this niche with a number of other species including and . Unlike these other members of the genus, may become invasive, crossing the epithelium of the nasopharynx and entering the bloodstream, where it rapidly proliferates causing a syndrome known as Invasive Meningococcal Disease (IMD).

Modelling evolutionary pathways for commensalism and hypervirulence in .

, the meningococcus resides exclusively in humans and causes invasive meningococcal disease (IMD). The population of is structured into stable clonal complexes by limited horizontal recombination in this naturally transformable species. is an opportunistic pathogen, with some clonal complexes, such as cc53, effectively acting as commensal colonizers, while other genetic lineages, such as cc11, are rarely colonizers but are over-represented in IMD and are termed hypervirulent.