The role of extracellular DNA in Neisseria biofilms

The genus Neisseria includes two human pathogens, Neisseria gonorrhoeae and Neisseria meningitidis, in addition to commensal species that also inhabit human and animal hosts. One of the features that occurs during neisserial host colonization is biofilm formation. In other bacteria, biofilm formation enables persistence as well as evasion of the host immune system. Extracellular DNA (eDNA) forms a major component of Neisseria biofilms and contributes to initial steps in their formation, as well as the structure and stability of the biofilm extracellular matrix. Here, we review the potential roles and sources of eDNA in Neisseria biofilms and its relevance to both pathogenic and commensal Neisseria spp. We also highlight the paucity in research on biofilm formation by commensal Neisseria and hope this will stimulate further research on the role of eDNA in nonpathogenic Neisseria.