Gram -positive bacilli, Anaerobic, Spore forming, Catalase-negative Flashcards
The toxins produced by the species are acquired through ingestion or open wounds that have
been contaminated with soil
Clostridium
Clostridium are motile with peritrichous flagella except for
C. perfringens, C. ramosum, and C.
innocuum
clostridium have swollen sporangia except for
C. perfringens
They are non-encapsulated except for
C. perfringens
They are carbohydrate fermenters except for
C. tatami and C.histolyticum
It is the most commonly isolated member of Clostridum in blood culture
Clostridum perfringens(Gas gangrene bacillus)
“Boxcar-shaped” bacilli with oral, subterminal spores
Clostridum perfringens(Gas gangrene bacillus)
Virulence factor of C. perfringens
Clostridum perfringens(Gas gangrene bacillus)
litmus milk-Colonies exhibit a stormy fermentation of milk
Clostridum perfringens(Gas gangrene bacillus)
(+) Reverse CAMP test-formation of an “arrowhead-shaped” zone of hemolysis
towards the test organism
Clostridum perfringens(Gas gangrene bacillus)
It is a life-threathening destruction of muscle and other tissues
It is accompanied by bullae, pain, swelling, serous discharge, discoloration and tissue
necrosis
Gas gangrene-Clostridum perfringens(Gas gangrene bacillus)
It is caused by the ingestion of Beta-enterotoxin in contaminated food
Improperly stored food allows the germination of the spores and growth of vegetative
bacteria
Symptoms: Bloody diarrhea and abdominal pain
Clostridial necrotizng enteritis or enteritis necroticans
It is a soil and environmental inhabitant
The endospores are found in the soil, dust, and feces of many farm animals
Clostridium tetani (Tack head bacillus)
Virulence factor of Clostridium tetani
Tetanospasmin (neurotoxin)
Microscopy: cells are with terminal spores and swollen sporangis that have a “drumstick” or
“tennis racket” appearance
Clostridium tetani (Tack head bacillus)
Biochemical test: (+) gelatinase, and indole; (-) lecithinase and lipase
Clostridium tetani (Tack head bacillus)
It is an endopeptidase that selectively cleaves the synaptic vesicle membrane protein,
synaptobrevin
It causes tension or cramping and twisting in skeletal muscles that surround the wound, and
tightness of the jaw muscle
Tetanospasmin
It is characterized by trismus or lock jaw and risus sardonicus or distorted grin
Tetanus
It occurs when the organism enters an open wound and spreads a potent toxin that mediates
generalized muscle spasm
Tetanus
Symptom: Muscular rigidity, difficulty in swallowing, rigidity of the abdomen, chest, back, and
limbs
Incubation period: 3 to 21 days
Tetanus
is contracted through the use of contaminated instruments on newborns
Tetanus neonatorum
It is found in soil and aquatic sediments
It is a potential bioterrorism agent
It is characterized by the presence of subterminal spores
Clostridium botulinum (―Canned food‖ bacillus)
Canned food bacillus
Clostridium botulinum (―Canned food‖ bacillus)
q
a neurotoxin that is considered as one of the most potent
natural toxins known to man
Botulism toxin
It selectively cleaves the synaptic vesicle membrane protein, synaptobrevin, thus preventing
exocytosis and the release of the neurotransmitter, acetlcholine
Botulism toxin
It requires a small amount to produce paralysis and death
Botulism toxin
Botulism antigens:
A to G
The antigens that cause human diseases are
A, B and E
It is characterized by double or blurred vision, impaired speech, difficulty in swallowing,
weakness, and paralysis
Botulism
It results from the ingestion of preformed toxin in preserved or meat-based food
Foodborne botulism
It is commonly caused by botulism toxin A
Foodborne botulism
It is an actual infection that is caused by ingesting the organism from honey or
through breastfeeding for infants
Infant botulism
It is the most common cause of antibiotic-associated diarrhea and pseudomembranous colitis
Clostridium difficile
It is acquired in the hospitals by individuals who are receiving antibiotics
Clostridium difficile
It is an “infection control dilemma” among hospitalized patients
Clostridium difficile
It ferments fructose-producing formic acid that changes the color of medium from pink to yellow
Clostridium difficile
Virulence factor: Toxin A (enterotoxin) and toxin B (cytotoxin)
Microscopy: Chains up to 6 cells that are aligned from end to end with oval, subterminal
endospores
Clostridium difficile
Cycloserine-cefoxitin-fructose agar (CCFA)-colonies exhibit a yellow color and a
“ground-glass” appearance
Clostridium difficile
BAP-Colonies exhibit a ―”horse-stable” odor; are non-hemolytic‘ and produce a
fluorescent chartreuse under a long UV light wave
Clostridium difficile
o Food and fecal specimens that are suspected of C. perfringens food poisoning should be
transported at
4 degrees celsius
Unacceptable specimes for anaerobic culture of C. difificile
a. swabs
b. sputum
c. bronchial washings
d. feces and effluents from ileostomy and colostomy
gastric and small bowel contents
It is used to differentiate the aerotolerant strains of Clostridum (catalase negative
from Bacillus (catalase-positive)
Reagent: 15% H2O2
(+) Result: Formation of bubbles
Catalase test
It is performed using an EYA plate and C. perfringens type A antitoxin.
(+) Result: Inhibition of the lecithinase reaction that is produced by C. perfringens
Direct Nagler Test
It is a definitive identification test for C. botulinum
It detects the presence of neurotoxins in serum or feces
Mouse neutralization test
It is used to confirm the presence of C. perfringens
(+) Result: Formation of an ―”arrowhead-shaped” zone of hemolysis at the
intersection of the 2 streaks toward the Clostridum isolates
Reverse CAMP test
It is the gold standard test for the detection of the C. difficile toxin type B
It requires two to three days to achieve a positive result
Cell culture cytotoxicity test
+) Lipase reaction: Colonies exhibiting a ―”mother-of-pearl” or ―”gasoline-on-water”
appearance
C. bitulinum and C. novyi
It is the most commonly isolated anaerobes from blood cultures
Bacteroides fragilis
It is a Beta-lactamase producer; and is non-motile and saccharolytic
It is a significant cause of intra-abdominal abscesses
Bacteroides fragilis
Bacteroides bile esculin (BBE) agar-Colonies exhibit a gray color and growth witj 20%
bile, and cause the blackening of the originally yellow-colored agar
Bacteroides fragilis
Biochemical test: (+) Esculin hydrolysis
Bacteroides fragilis
It is a significant cause of intra-abdominal abscesses
Bacteroides fragilis
It is the most common cause of actinomycosis
Actinomyces israelii
It is part of the indigenous microbiota of the oral cavity
Actinomyces israelii
It is frequently isolated from blood cultures, but its presence also indicates contamination of the
patient‘s skin due to the improper cleansing of the site prior to a phlebotomy
Propionobacterium acnes
The species of this genus are pleomorphic, Gram-positive rods
It non - motile, and may also be considered as an aerotolerant anaerobe
Lactobacillus
It is part of the indigenous microbiota of the mouth, GIT, and vaginal canal
It protects the female genital tract from urogenital infections
Lactobacillus acidophilus
Differential medium: Tomato juice agar (pH 3 to 4)
Lactobacillus acidophilus
Biochemical test: (-) Catalase , H2S and esculin hydrolysis
Lactobacillus acidophilus
