LEC.3 Flashcards
Gram-positive and spore-forming bacilli
Clostridium
most are strictly anaerobes
widely distributed in soil and water
some are normal flora in the GI tract of man and other animals
Clostridium
describe morphology of clostridium
Are endospore forming large Gram-positive bacilli
How do we acquire diseases from this group of organisms?
Through the inoculation of the bacilli spores, ibig sabihin nagkakaroon tayo ng sakit kapag nagmultiply yung mga spores. Or pwede ring ingestion.
C. perfringens aka
C. welchii
Bacillus aerogenes capsulatus
Gas gangrene bacillus
Do not produce spores in ordinary media
C.perfringens
has spores located at the terminal end of the cell
C.tetani
C. tetani has spores located at the terminal end of the cell, giving it a characteristic
tack-head, drumstick, lollipop, and tennis racket appearance
C.tetani aka
tack-head bacillus
all clostridium are motile except
C.perfringens
type of media used for isolation of clostridium spp.
nonselective,selective, and liquid media
supplemented anaerobic Blood Agar
Nonselective
C.perfringens hemolysis in nonselective media
double zone of hemolysis
double zone of hemolysis
beta hemolysis surrounded by alpha hemolysis
Egg yolk agar
nonselective,differential
nonselective,differential media allows differentiation based on
- Lecithinase(white precipitate)
- Lipase(sheen around surface of colonies)
- Protease production(clearing)
C.botulinum aka
canned good bacillus
agent of canned good-bacillus-botulism
C.botulinum
example of antigenic toxin produce by botulinum
botulism toxin
different type of toxins of C.botulinum
Type A
Type B
Type E
Type F
Type G
most common and potent type of toxin in c. botulinum
Type A
Toxins of botulinum block release of
acetylcholine
C.botulinum causes
flaccid paralysis
It works at the neuromuscular junction and in the
autonomic nervous system to prevent the release of
the neurotransmitter acetylcholine.
C.botulinum
part of C.botulinum cleaves proteins that mediate the fusion
of synaptic vesicles with the cell membrane and the
subsequent release of acetylcholine.
toxic part
Symptoms appear [C.botulinum]
18-24 hours after toxin ingestion
[C.botulinum] visual disturbances
inability to swallow, speech
difficulties, bulbar paralysis(ptosis
usually caused by respiratory
paralysis(diaphragm), cardiac arrest
Death
In infants: poor feeding, weakness and the characteristic
flaccid paralysis is found caused by [C.botulinum]
hypotonia
C.botulinum may also cause
Sudden Infant Death Syndrome
the organism germinates in the wound abscess
Wound botulism
TRIAD OF BOTULISM
Symmetric descending flaccid paralysis(with
prominent bulbar involvement)
Absence of fever
Intact sensorium
[C.botulinum] Demonstration of toxin by
passive hemagglutination or radioimmunoassay
[C.botulinum] adults specimen of choice
Serum and left-over food
[C.botulinum] Infants specimen of choice
stool
Anaerobic, gram-positive, spore-forming rod
C.tetani
C.perfringens
C.difficile
Disease is tetanus with characteristic [C.tetani]
backward arching of the back muscles
C.tetani toxin is produced by
vegetative cells that reaches the
CNS
C.tetani virulence factors
spores
glycine
gamma-aminobutyric acid
[C.tetani] terminally located, therefore germinate under
anaerobic conditions
Spores
[C.tetani] inhibits muscle contraction
Glycine
Gamma-aminobutyric acid
Lockjaw
trismus
Risus sardonicus
patient has a distorted grin
Opisthotonus
Arching of the back
two enterotoxins proiduced [C.tetani]
A hemolysin
Tetanospasmin
can travel to the CNS humorally through blood and lymph, or neurally through tissue spaces of the peripheral nerves
Tetanospasmin
Accounts for the lockjaw and opisthotonus
Tetanospasmin
C. perfringens invasive infection
myonecrosis and gas gangrene
C.perfringens produces an enterotoxin which is a common cause of
food poisoning
C.perfringens appearance on BAP
double zone of hemolysis around colonies
Nonmotile but with rapidly spreading growth on culture
media
C.perfringens
Produces milky or stormy fermentation due to the excessive gas production
Milk Media
C.perfringens Virulence Factors
Lecithinase
Alpha Toxin
Delta/Theta Toxin
When grown in EYA, there is a white precipitate
Lecithinase
Responsible for incomplete hemolysis in C.perfringens
Alpha toxin
Responsible for complete hemolysis in C.perfringens
Delta/Theta toxin
Localized edema and erythema with gas formation in
soft tissue, and generally not painful
Cellulitis
Accumulation of pus in muscle planes without muscle
necrosis or systemic symptoms
Suppurative Myositis
Infection spreads 1-3 days to produce crepitation
(cracking or rattling sound) in the subcutaneous tissue
and muscle
Myonecrosis
discharge rapidly progressing necrosis and fever
foul-smelling
Myonecrosis leads to
Toxemia,shock, and death
Acute necrotizing destruction of the jejunum with
abdominal pain, vomiting, blood diarrhea and
peritonitis
Necrotizing Enteritis
C.perfringens specimen
material from wounds, pus, and tissue
Special Stain C.perfringens
gram positive rod with sporeS
C.perfringens Reverse CAMP test
positive
final phase by which viral cells infect cells
cytopathic effect
potent enterotoxin, cytotoxic activity, binds to
the brush borders of the GUT at the receptor site
Toxin A
potent cytotoxin
Toxin B
MOT C.difficile
fecal-oral route
Non-bloody diarrhea associated with
pseudomembranes Yellow-White Plaques on the
colonic mucosa.
PSEUDOMEMBRANOUS COLITIS
