FINALS L3 Flashcards
Clostridium Morphology
endospore forming large gram positive bacillus
we acquired dxs from clostridium through what?
through the inoculation of the bacilli spores
Clostridium welchii
Clostridium perfringens
Bacillus aerogenes capsulatus
Clostridium perfringens
Gas gangrene bacillus
Clostridium perfringens
Do not produce spores in ordinary media
Clostridium perfringens
presence of terminal spores which gives its
TACK HEAD OR DRUMSTICK OR LOLLIPOP OR TENNIS RACKET APPEARANCE
Clostridium tetani
(Clostridium)
All are motile except ____
Clostridium perfringens
Primary isolation used for Clostridium
Nonselective
Selective
Liquid media
C. perfringens produces ____ in nonselective supplemented anaerobic blood agar
a classic DOUBLE ZONE OF HEMOLYSIS (beta hemolysis surrounded by alpha hemolysis)
(Clostridium)
Nonselective, differential medium
Egg yolk agar
(Clostridium)
allows differentiation based on
Lecithinase (white precipitate)
Lipase (sheen around surface of colonies)
Protease production (clearing)
canned good bacillus
Clostridium Botulinum
agent of canned good bacillus botulism
Clostridium botulinum
(Clostridium Botulinum)
Types of toxins
A - most common/ potent
B
E
F
G
(Clostridium botulinum)
Toxins block the release of ____
acetylcholine
causes flaccid paralysis
Clostridium botulinum
Clostridium botulinum
MOT
INGESTION of food containing the microorganism and its spores
(c. botulinum)
symptoms
visual disturbances
inability to swallow
speech difficulties
bulbar paralysis (ptosis)
may cause Sudden Infant Death Syndrome
Clostridium botulinum
organism germinates in the wound abcess
wound botulism
Triad of botulism
- symmetric descending flaccid paralysis
- absence of fever
- intact sensorium
Clostridium botulinum
DIAGNOSIS
ADULT:
INFANT:
demonstration of toxin by passive hemagglutinaton or radioimmunoassay
ADULT: serum and left-over food
INFANT: stool
tack head bacillus
Clostridium tetani
Clostridium tetani
VIRULENCE FACTOR
Spores - germinate anaerobically, terminally located
Glysine and GABA (gamma-aminobutyric acid) - inhibits muscle contraction
Clostridium tetani causes lock jaw. What’s the characteristic?
risus sardonicus or distorted grin
other name of lock jaw
trismus
arching of the back
ophisthotonus
Clostridium tetani incubation period
4-5 days up to weeks
Exotoxins that Clostridium tetani produces
Hemolysin
Tetanospasmin
can travel to the CNS
humorally through blood and lymph, or
neurally through tissue spaces of the
peripheral nerves. Leads to lock jaw and
opisthotonus
Tetanospasmin
anaerobic, large gram-positive, spore-forming rods
CLOSTRIDIUM PERFRINGENS
Does not form spore in ordinary media
Clostridium perfringens
Produces invasive infection including myonecrosis
and gas gangrene
C. perfringens
C. perfringens produces an enterotoxin which is a common cause of
Food poisoning
C. Perfringens in BAP
Double zone of hemolysis around colonies
(C. perfringens)
T or F
growth on egg-yolk agar
T
(C. perfringens)
nonmotile but with rapidly spreading growth on ____
media
culture
C. perfringens
VIRULENCE FACTOR
●Lecithinase - white precipitate in egg yolk agar
● Alpha toxin
● Delta/Theta toxin
○Theta toxin- complete hemolysis
○ Alpha toxin- incomplete hemolysis
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 in the subcutaneous tissue and muscle
●Foul-smelling discharge, rapidly progressing
necrosis and fever
● Toxemia, shock and ultimately death.
MYONECROSIS
● This usually follows the ingestion of large
numbers of clostridia that have grown in
warmed meat dishes
● Self-limiting but produces Diarrhea without
vomiting and fever
● Lasts only 1-2 days
FOOD POISONING
Acute necrotizing destruction of the jejunum
with abdominal pain, vomiting, bloody
diarrhea and peritonitis
NECROTIZING ENTERITIS
C. perfringens
SPECIMEN
material from wounds, pus and tissue
C perfringens
Special stain
(appearance niya ata to)
gram-positive rod with spores
C perfringens
Growth on BAP:
double zone of hemolysis
C. perfringens
Reverse CAMP test:
+
C. perfringens
Lecithinase
+
C. perfringens
SPECIAL STAIN
Schaeffer-Fulton
Anaerobic, gram-positive, spore-forming rods
CLOSTRIDIUM DIFFICILE
C. difficile
Exotoxin in stool detected by ____ on cultured
cells or ELISA
cytopathic effect
Toxins of C. difficile
Toxin A
Toxin B
potent enterotoxin, cytotoxic activity, binds to
the brush borders of the GUT at the receptor site
Toxin A
potent cytotoxin
Toxin B
C. perfringens
MOT
Fecal- oral route
C. difficile
clin. manifestations
Pseudomembranous colitis
C. difficile in culture medium
white colonies with distinctive
horse-stable odor
C. difficile in CCFA
yellow, groundglass
appearing colonies
Other Clostridium
Clostridium tertium : wound infections
Clostridium septicum : nontraumatic myonecrosis in
immunocompromised patients
Clostridium sordelii : toxic shock syndrome associated
with septic abortion
Small, gram positive, aerobic to microaerophilic
coccobacilli that are non acid fast and non spore
formers
● Facultative anaerobe
LISTERIA MONOCYTOGENES
LISTERIA MONOCYTOGENES
motile on broth
Tumbling motility
LISTERIA MONOCYTOGENES
appearance on semi-solid media
umbrella-like☂️ or inverted Christmas tree
Can Listeria Monocytogenes grow at 4°C and in high salt concentration (cold enrichment)?
Yes or No
Yes
Listeria monocytogenes
MOT
food ingestion contaminated with the organism;
transplacental (mother-child)
Listeria 2 known specie:
human:
animals:
L. monocytogenes
L. ivanovii
LISTERIA
Grow best at
Slow growth at
Poor growth at
25-35°C
4°C
42°C
LISTERIA
Virulence Factors
● Internalin (A and B) : interacts with E-cadherin on the
surface of cells
● Listeriolysin O (LLO) : oxygen labile; escape from
phagosomes
● Actin rockets (actin polymers) : propels the bacteria
through the membrane of one human cell and into
another
Virulence test in L. monocytogenes
Anton’s Test or Ocular test of Anton
(L. monocytogenes)
Clin. Manifestation
NEONATAL DISEASE
DXS IN HEALTHY ADULTS
LISTERIOSIS
Early onset of neonatal dx
Granulomatosis infantiseptum
Late onset of neonatal dx
Acquired in utero dissemination meningitis