Anaerobiosis in oral cavity
Lecter-15 •
Dr.Baha,H. Al-Amiedi •
Ph.D.Microbiolgy •
Anaerobiosis in oral cavity
There have been many attempt to identify •
the mechanism that allow clostridia &other
Anaerobic to colonize in oral cavity •
1-It is known that the oxidation-reduction •
potential of oral cavity is suitable for species
of clostridia,such as :
1-clostridium perfringens. •
2-clostridium histilyticum •
2-Free-flowing saliva has high positive redox •
potential which shifts towered the
Negative side with the elapse of time. •
3-salive is stagnant area, such as the •
periodental pocket and dental interproximal
space where oxygen uptake may be
retarded,has redox potential enough to
prompte anaerobic growth
. •
4-other factors that may be acting to •
promote suitable growth conditions in saliva
for oral anaerobes include the the lack of
peroxidase in saliva,the presence of salivary
catalase and the depletion of oxygen by the
aerobic flora,
Clostridium
Clostridiun are gram positive,obligate •
anaerobic,the endo spore are wider than bacilli
bodies may be of central or terminal
In position &spherical or oval in shape •
Clostridium are widely distributed in soil and in •
the intestinal tract of human &other animals it is
responsible for disease:
1-tetanus •
2-gas gangrene •
3-botulism •
4-psedomembranoud colitis •
Spores Pleomrhic (elongated, spindle
Most are obligate
anaerobes produce neuro
histo toxins
Clostridium tetani
Anaerobic gram-positive, spore-forming •
bacteria characteristic drumstick
appearance because the terminal spore.
Spores found in soil, animal feces; may •
persist for months to years
Multiple toxins produced with growth of •
bacteria
Tetanospasmin estimated human lethal •
dose = 2.5 ng/kg
Tetanus gram staine
tetanus
Transmission
Spores of clostridium tetani are commonly •
Found in soil&intestinal tract of human& •
Animals. •
infection associated with: •
1-puncture wounds. •
2-contaminated injuries •
3-sever burns •
4-Non-sterile surgary, •
tetanus
Mode of Action of
Tetanus Toxin
Anaerobic conditions allow germination of •
spores and production of toxins
Toxin binds in central nervous system •
Interferes with neurotransmitter release to •
block inhibitor impulses
Leads to unopposed muscle contraction and •
spasm
Mechanism of Action of Tetanus Toxin
Mode of action tetanus toxin
Tetanus infection
Tetanus infection
Tetanus Complications
1-Laryngospasm •
2-Fractures •
3-Hypertension
4-Nosocomial infections •
5-Pulmonary embolism •
6-Aspiration pneumonia •
7-Death •
•
Neonatal Tetanus
Generalized tetanus in newborn infant •
Infant born without protective passive •
immunity
Estimated >215,000 deaths worldwide in •
1998
Tetanus infection
Laboratory diagnosis
1-smear from wound material show gram •
positive bacilli with dram stick appearance.
2-cultur is more dependable by use in •
cooked meat &lactose egg yolk medium
On blood agar produce in anaerobic •
condition hemolysin(tetanolysin)
Tetanus gram stane