Pathogenic Neisseria, N. meningitidis and N. gonorrhoeae that respectively cause meningitis and gonorrhea, form biofilms in vivo, and while in these structures, display increased resistance to antibiotics, compromising treatment. Biofilm formations (BF) are aggregates of microorganisms encased in an extracellular matrix. Closely related commensal Neisseria species belong to the normal bacterial flora of the human oral and nasopharynx, but are largely unstudied. This research will characterize BF by N. cinerea and the phenotypic diversity of its colonies, in the presence or absence of subinhibitory concentrations of antibiotic. We adapted the Poltak dynamic BF model and developed an instrument specifically for the purpose of BF studies. We grow fluorescently-labelled N. cinerea biofilms on plastic beads under shaking conditions, with or without antibiotic, and collect biofilm cells from the beads to characterize the density of the biofilms and the phenotypic diversity of colonies forming the biofilms. This study will be the first to characterize biofilm formation by N. cinerea using the dynamic model and to study the impact of biofilms on antibiotic resistance levels. The goal of this work is to inform future studies of pathogenic Neisseria biofilm and antibiotic resistance behavior.
