Microbiology Gram-Negative Cocci - Neisseriales and Neisseria meningitidis Phylogenetic Tree of the Proteobacteria - sorted by the difference in 16S ribosome Neisseria sp. is a beta proteobacteria Neisseriales Eikenella and Kingella can cause opportunistic infections when the immune system is low Order - Neisseriales Family - Neisseriaceae Genus - Neisseria Species - N. gonorrheae Aka - Gonococcus Order - Neisseriales Family - Neisseriaceae Genus - Neisseria Species - N. meningitidis Aka - Meningococcus Order - Neisseriales Family - Neisseriaceae Genus - Eikenella Species - E. corrodens Order - Neisseriales Family - Neisseriaceae Genus - Kingella Species - K. kingae Eikenella 1958 - Eiken Kingella 1960 - King Eikenella and Kingella are pleiomorphic and gram-negative Eikenella and Kingella colonies the oropharynx/URT and they can cause deep-seated bone infections if they become invasive; they are opportunistic pathogens. Neisseria - characteristics They are non-motile They have a gram-negative cell wall, which has two membranes, LOS and a thin peptidoglycan layer. OMPs Pilus outer membrane peptidoglycan porin periplasmic space LOS lipoprotein Neisseria have a diplococcus shape: plasma membrane
Microbiology · Flat sides - coffee bean shape · Division plane · 0.6-1 um Neisseria have fastidious growth requirements (hard to please, need to give them a lot of factors) · Amino Acids, Purines/pyrimidines (they require cysteine) . Vitamins · 35-37°C, humid · Aerobic / Capnophilic (like a lot of CO2) - Like raised CO2 5% Oxidase positive - look for the presence of an enzyme to cause a colour change (enterococcus are oxidase-negative) Catalase-positive: H202 > 02 & H2O (catalase is an enzyme produce to break down hydrogen peroxide into oxygen and water) just drop a bit of hydrogen peroxide onto the organisms on the slide, and if it bubbles there is catalase present. Reaction to 3% H2O2 · Gonococcus - strong positive · Meningococcus - variable positive Acid from sugars; Neisseria ferments sugars in acids. Look at the metabolism of the sugars, as different species ferment different sugars. Useful for differentiating Neisseria sp. Acid from Glucose Meningococcus + Gonococcus + Maltose + Gonococcus and Meningococcus are organisms that associate with the epithelial lining. They associate in different areas. Meningococcus Commensal Target epithelium Invasive Purulent infection + Nasopharynx Gonococcus Genital tract + Carry meningococcus as a commensal organism of the nasopharynx. However, we do not carry gonococcus as a commensal. The meningococcus is the most invasive out of both of them. They both cause purulent infection; associated with pus and they are associated with neutrophils (cause the yellow of the pus). Neisseria - typical Gram negative envelope Neisseria - Pili They are long proteinatious extensions from the pathogen surface and they are important in adhesion, thus important for pathogenesis. Mediates attachment that generates a focus for infection, as they are then able to invade. At the tip there is an adhesion called Pil C, which binds to CD46 that is an adhesive receptor that the pillus can bind to and then invade. Repeating sub-units of pilin (pil E) are expressed. There is the ability to