CLOSTRIDIUM Flashcards
Most commonly causes myonecrosis
C. perfringens
Clostridum spp.
Specie
C. perfringens, C. novyi, C.
histolyticum, C. bifermentans, C. sordellii, C. innocuum, C. botulinum and C. tetani
Clostridum spp.
Histotoxic
C. perfringens, C. novyi, C. histolyticum, C. septicum, C. bifermentans
Obligate anaerobes, catalase negative, Gram- positive, spore-forming bacilli
CLOSTRIDIUM
acquired through ingestion or open wounds that have been contaminated with soil
Toxins of Clostridium
Collagenase, hyaluronidase, lecithinase (soil destruction) and phospholipase
Virulence contributors
Carbohydrate fermenter; except
C. tetani and C. histolyticum
Form endospores anaerobically
CLOSTRIDIUM
Motile; except
C. perfringens, C.
ramosum and C. innocuum
Have swollen sporangia except
C. perfringens and C. bifermentans
Non-encapsulated; except
C. perfringens
Single haemolytic reaction; except
C. perfringens
Most commonly isolated member
CLOSTRIDIUM PERFRINGENS (GAS GANGRENE BACILLUS)
a-toxin and enterotoxin
Virulence factor of C. perfringens
“Boxcar-shaped” bacilli with
subterminal spores
Microscopy of Clostridium perfringens
o (+) Lecithinase – EYA (egg yolk agar)
o (+) Nagler test – Lecithovitellin
o (+) Reverse CAMP Test –arrowhead-
shaped zone of hemolysis towards test
organism
Biochemical
dome-shaped and grayish white with double zones of hemolysis
▪ Alpha and beta zones (double zones)
Clostridum perfringens on BAP
Stormy fermentation of milk
Lithmus milk
o Gas gangrene (myonecrosis)
o Clostridial necrotizing enteritis or Enteritis necroticans
Related Disease:
Blister that has water inside,
tissue necrosis
Gas gangrene (myonecrosis)
▪ Ingested beta enterotoxin in a contaminated food.
▪ Bloody diarrhea, abdominal pain
Clostridial necrotizing enteritis or Enteritis necroticans
Endospore is usually in dust, soil, or dirt/fecal(?) of animals in the farm
CLOSTRIDIUM TETANI (TACK HEAD BACILLUS)
Tetanospasmin (neurotoxin)
Virulence factor of CLOSTRIDIUM TETANI (TACK HEAD
BACILLUS)
Drumstick or tennis-racket
appearance (terminal spores)
Microscopy of CLOSTRIDIUM TETANI
(+) gelatinase and indole
(-) Lecithinase and lipase
Biochemical test of CLOSTRIDIUM TETANI
Tetanus, Tetanus neonatorum
Infection related to CLOSTRIDIUM TETANI
slow, anaerobic, heavy, smooth,
and swarming growth, narrow zone of b hemolysis
CLOSTRIDIUM TETANI ON BAP
endopeptidase cleaves the
synaptic vesicle membrane protein,
Tetanospasmin
Cause tension or cramping and twisting
in skeletal muscles that surrounds the
wound and tightness of jaw muscles.
Synaptobrevin
Characterized by trismus or lock jaw
and risus sardonicus or distorted grin. IP: 3 to 21 days.
Tetanus
muscle rigidity, difficulty of
swallowing, rigidity of the abdomen,
chest, back & limbs
Symptoms of Tetanus
Usually found in soil and aquatic sediments
CLOSTRIDIUM BOTULINUM (“CANNED FOOD”
BACILLUS)
- Potential bioterrorism agent
- Presence of subterminal spores
CLOSTRIDIUM BOTULINUM (“CANNED FOOD” BACILLUS)
Botulism toxin
VF of CLOSTRIDIUM BOTULINUM
-b-haemolytic colonies
CLOSTRIDIUM BOTULINUM on BAP
Botulism
iNFECTION RELATED TO CLOSTRIDIUM BOTULINUM
neurotoxin that is considered
as one of the most potent natural toxins known
to man
Botulism toxin
A to G (7
antigenic types)
Botulism antigens/agent
A, B and E
Cause human disease
double or blurred vision, impaired
speech, difficulty in swallowing, weakness and
paralysis.
BOTULISM
Usually due to ingestion
of the preform toxin in
preserved or meatbased food or canned
goods.
* Commonly caused by
botulism toxin A.
Foodborne botulism
Actual infection caused
by ingesting the
organism from the raw
honey or through
breastfeeding for
infants
Infant botulism
Most Common cause of antibiotic-associated
diarrhea and pseudomembranous colitis (bloody
diarrhea with necrosis of colonic mucosa).
CLOSTRIDIUM DIFFICILE
Acquired in hospitals by individuals who are
receiving antibiotics
CLOSTRIDIUM DIFFICILE
“Infection control dilemma” among hospitalized
patients
CLOSTRIDIUM DIFFICILE
Ferments fructose-producing formic acid that
changes the color of medium to pink to yellow
CLOSTRIDIUM DIFFICILE
Toxin A (enterotoxin) and
Toxin B (cytotoxin).
VF of CLOSTRIDIUM DIFFICILE
Chains up to 6 cells that are
aligned from end to end with oval subterminal endospores.
Microscopy of CLOSTRIDIUM DIFFICILE
colonies exhibit yellow color
and a “ground-glass” appearance.
Cycloserine-cefoxitin-fructose agar
(CCFA) on CLOSTRIDIUM DIFFICILE
“Horse stable” odor; nonhaemolytic and produce fluorescent
chartreuse. (under UV)
CLOSTRIDIUM DIFFICILE on BAP
Transport promptly to the laboratory under
anaerobic condition or with minimal
O2
exposure
If cannot processed immediately: should be kept
in room temp.
must be collected at the actual site;
swabbing of mucosal surface is insufficient.
Specimen
best specimen for anaerobic
culture
Needle aspiration
only be used when performing
aspiration is not possible or if a biopsy specimen
is not available
Swabs
Swab should be placed into
a 0.5 mL sterile thioglycolate broth
Food and fecal specimens that are suspected of
C. perfringens food poisoning should be
transported at 4°C.
UNACCEPTABLE SPECIMENS FOR
ANAEROBIC CULTURE
Swabs
Sputum
Bronchial washings
Feces and effluents from ileostomy and colostomy, and gastric and small bowel contents.
C. ramnosum and C. clostridioforme
are gram negative
not observed in Gram-stained
smears of clinical specimens that contain
clostridia, unless incubated for many days
Spores
Anaerobic blood agar,
thioglycollate, EYA, CCFA, PYG, brucella blood
agar, PEA and CNA.
Culture media
pre-reduced anaerobically
sterilized (PRAS) medium and Amies medium.
Transport media
Inhibit gram negative coliforms
CCFA
pH indicator in CCFA
neutral red
detect lecithinase and lipase activity.
EYA
Catalase negative; Rgt:
15% H2O2
o Using EYA plate and C. perfringens type
A antitoxin.
Direct Nagler Test
(+): Inhibition of the lecithinase reaction
that is produced by C. perfringens
Direct Nagler Test
Definitive identification test for C.
botulism
Mouse Neutralization Test
(+) Arrowhead-shaped zone of
hemolysis at the intersection of the two
streaks towards clostridium isolates,
Reverse CAMP Test
Confirm the presence of C. perfringens.
Reverse CAMP Test
Gold standard test for detection of C.
difficile toxin. Requires 2-3 days to
achieve positive result
Cell Culture Cytotoxicity Test
(+) Lecithinase and organisms positive
opaque zone
▪ C. perfringens, C. bifermentans,
C. novyi
(+) Lipase and organisms positive
“Mother of pearl” app. Or gasoline on water appearance.
▪ C. botulinum, C. novyi
o Cleaves the synaptic vesicle membrane
protein, synaptobrevin.
o Preventing exocytosis and the release
of the neurotransmitter, Acetylcholine.
o Small amount to produce paralysis and
death
Botulism toxin
