M10 - gram -ve Flashcards
what are the 4 main groups in gram-ve bacteria?
- cocci
- strict anaerobes
- facultative anaerobes
- curved rods
give a general description of Neisseria
- gram -ve, facultative/aerobic
- non-motile
- pathogens:
neisseria gonorrhoeae and N meningitidis
not considered to be normal oral flora
which oral neisseria in dental plaque saccharolytic produces polysaccharide and a yellow green pigment?
neisseria subflava - most commonly isolated
which oral neisseria is saccharolytic and polysaccheride producing but does not produce a pigment?
neisseria sicca
which gram - bacteria has a facultative intracellular lifecycle that allows it to infect tonsillar B cells?
moraxella catarrhalis
How does moraxella catarrhalis complicates antibiotic therapy?
most strains produce a Beta-lactamase
which gram -ve anaerobic cocci makes up to 20% of plaque flora ?
veillonella- do not ferment carbohydrates
how does veillonella parvula raise pH?
catabolises lactic acid (anaerobe) to weaker organic acids
what is the general link between Veillonella parvula and caries?
High number of V. parvula raise pH but reduce cariogenecity of plaque
list 3 motile GNABs
- selenomonas
- centipeda
- helicobacter
List 6 non motile GNABs
Bacteriodes porphyromonas prevotella Tannerella fusobacterium leptotrichia
selenomonas (non-motile) are cresent shaped bacteria with many flagellae, what are they reportedly associated with?
aggressive forms of periodontitis
where has helicobacter been found?
-reported in dental plaque (Motile)
which type of anaerobic Gram-ve bacilli are a large proportion of oral bacteria?
non-motile
which bacteriode is found in the mouth and GI tract?
bacteroides fragilis
which two bacteria are commonly found when the pocket deepens, gingiva starts to recede and bone begins to be lost?
- porphyromomas gingivalis and prevotella intermedia
which 3 bacteriodes produce a dark pigment and are asaccharolytic?
- prevotella species
- porphyromonas species
- tannerella forsythia
list key features of porphyromonas?
- dark/purple pigmented GNAB
- asaccharolytic ; produces protease to access them
- P.gingivalis considered a periodontopathogen
features of prevotella?
- dark purple pigment
- gingival sulcus and peri pocket
- Prevotella intermedia; numbers correlate with periodontitis severity
which species is non-pigmented and is isolated from root canals and periodontal pocket?
P.dentalis
how can black pigmented bacteria (iron requiring) be treated with blue light?
causes excitation –> produces O2 reactive which destroys lipids proteins and nuclei acids
plaque causing gingivitis (streptococcus)–>
plaque grows forming pockets is actinomyces –> when pocket deepens (prophyromomas gingivalis and prevotella intermedia
for porphyromomas, what is the reason for dark pigment?
iron molecules on surface
