Practice Test for Gram Pos. Bacilli
Flashcard 1
Q: What is the common name for Bacillus anthracis?
A: Anthrax bacillus.
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Flashcard 2
Q: What is the virulence factor of Bacillus anthracis?
A: D-glutamate capsule and the production of exotoxins (lethal factor, edema factor, and protective antigen).
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Flashcard 3
Q: How is Bacillus anthracis transmitted?
A: It is transmitted through contact with infected animals or animal products.
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Flashcard 4
Q: What diseases are caused by Bacillus anthracis?
A: Anthrax, including cutaneous anthrax, pulmonary anthrax (Ragpicker's disease), and intestinal anthrax.
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Flashcard 5
Q: What are the laboratory diagnostics for Bacillus anthracis?
A: String of pearl appearance on MHE agar, Gram stain showing boxcar morphology, and Medusa head colonies on BAP.
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Flashcard 6
Q: What are the two types of toxins produced by Bacillus cereus?
A: Enterotoxin and pyogenic toxin.
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Flashcard 7
Q: What are the two forms of disease caused by Bacillus cereus?
A: Diarrheal type (watery diarrhea) and emetic type (vomiting after consuming fried rice).
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Flashcard 8
Q: What is a key feature of Bacillus subtilis in the lab?
A: It is a common laboratory contaminant and the source of Bacitracin.
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Flashcard 9
Q: Which bacterium is known as the gas gangrene bacillus?
A: Clostridium perfringens.
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Flashcard 10
Q: What test is used to detect Clostridium perfringens' alpha toxin?
A: Lecithinase test (Naegler Reaction).
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Flashcard 11
Q: What are the diseases caused by Clostridium perfringens?
A: Food poisoning, gas gangrene, and myonecrosis.
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Flashcard 12
Q: What is the virulence factor of Clostridium tetani?
A: Tetanospasmin (neurotoxin causing spastic paralysis).
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Flashcard 13
Q: What is the common name for Clostridium tetani?
A: Tetanus bacillus or drumstick bacillus.
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Flashcard 14
Q: What disease is caused by Clostridium botulinum?
A: Botulism, which causes flaccid paralysis.
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Flashcard 15
Q: What is the common source of Clostridium botulinum infection?
A: Ingestion of preformed toxin in improperly processed canned goods.
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Flashcard 16
Q: What is a key diagnostic test for Clostridium difficile?
A: Cytotoxin detection and culture on CCFA agar, where colonies produce a horse stable odor.
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Flashcard 17
Q: What are the virulence factors of Clostridium difficile?
A: Toxin A (enterotoxin) and Toxin B (cytotoxin).
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Flashcard 18
Q: What are the main types of Clostridium infections?
A: Histotoxic (e.g., gas gangrene), neurotoxic (e.g., tetanus and botulism), and toxigenic enteric (e.g., Clostridium difficile infections).
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Flashcard 19
Q: What is the diagnostic test used for Clostridium perfringens?
A: Reverse CAMP test, showing enhanced hemolysis as an arrowhead zone of beta hemolysis.
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Flashcard 20
Q: What medium is used to culture Clostridium perfringens?
A: Duncan and Strong medium, known for producing spores and starch fermentation.
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Flashcard 21
Q: What disease does Clostridium tetani cause?
A: Tetanus, which includes risus sardonicus (sardonic smile) and muscle spasms.
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Flashcard 22
Q: What is the laboratory diagnosis for Clostridium botulinum?
A: Laboratory confirmation is done by demonstrating the toxin in stool, food, or wound, along with culturing the organism.
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Flashcard 23
Q: What are the common symptoms of botulism?
A: Flaccid paralysis, difficulty breathing, and muscle weakness, often due to the ingestion of preformed toxins.
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Flashcard 24
Q: How is Clostridium difficile acquired?
A: It is commonly acquired in hospitals, particularly by individuals receiving antibiotics that disrupt normal gut flora.
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Flashcard 25
Q: What is the key characteristic of Clostridium tetani spores?
A: The spores are terminally located, giving the bacterium a "drumstick" or "tennis racquet" appearance.
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Flashcard 26
Q: What medium is used to detect Clostridium difficile in culture?
A: Cycloserine Cefoxitin Fructose Agar (CCFA), which develops colonies with a horse stable odor.
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Flashcard 27
Q: What condition is associated with Clostridium difficile infection?
A: Pseudomembranous colitis, often caused by antibiotic treatment disrupting the gut flora.
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Flashcard 28
Q: What is the treatment option for severe gas gangrene caused by Clostridium perfringens?
A: Hyperbaric oxygen therapy, which increases oxygen levels to inhibit anaerobic bacterial growth.
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Flashcard 29
Q: What is the common name for Bacillus cereus and the associated disease?
A: Known as the "Fried Rice Bacillus," it causes food poisoning, particularly after consuming reheated fried rice.
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Flashcard 30
Q: How does Bacillus anthracis appear on plated media?
A: It forms colonies with a "Medusa head" or "lion head" appearance, and is non-hemolytic on blood agar.
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Flashcard 31
Q: What is the main clinical feature of cutaneous anthrax?
A: The formation of a "black eschar" at the site of infection, which is a black necrotic lesion.
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Flashcard 32
Q: What is the difference between the diarrheal and emetic forms of Bacillus cereus food poisoning?
A: The diarrheal form causes watery diarrhea without fever, while the emetic form causes profuse vomiting after ingesting reheated fried rice.
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Flashcard 33
Q: What is the virulence factor of Clostridium perfringens responsible for gas gangrene?
A: Alpha toxin, which causes tissue necrosis and gas production in muscle tissues.
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Flashcard 34
Q: How is Clostridium tetani neurotoxin (tetanospasmin) associated with its clinical symptoms?
A: Tetanospasmin blocks the release of neurotransmitters, leading to spastic paralysis, muscle rigidity, and characteristic muscle spasms.
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Flashcard 35
Q: What type of paralysis does Clostridium botulinum cause?
A: Flaccid paralysis, which is the opposite of the spastic paralysis caused by tetanus.
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Flashcard 36
Q: How does Clostridium botulinum toxin act on the body?
A: The toxin inhibits acetylcholine release at neuromuscular junctions, leading to muscle weakness and paralysis.
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Flashcard 37
Q: What are the characteristics of Clostridium difficile colonies on BAP (Blood Agar Plate)?
A: Colonies exhibit fluorescence under ultraviolet light and have a chartreuse (yellow-green) color.
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Flashcard 38
Q: What is the laboratory method used to confirm the presence of Clostridium difficile toxins in a patient sample?
A: Cytotoxin detection assay from freshly passed stool, which identifies Toxin A and Toxin B.
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Flashcard 39
Q: What specific feature distinguishes Bacillus anthracis spores?
A: Bacillus anthracis spores are centrally located and can remain viable in the soil and animal products for decades.
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Flashcard 40
Q: What laboratory technique is used to differentiate Bacillus species from Clostridium species?
A: The catalase test: Bacillus is catalase-positive, while Clostridium is catalase-negative.
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Flashcard 41
Q: What is the typical morphology of Bacillus anthracis on Gram-stained smears?
A: Bacillus anthracis has a boxcar-like morphology due to its square-ended bacilli, giving a "bamboo rod" appearance.
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Flashcard 42
Q: What is a key diagnostic test for Clostridium tetani?
A: Gelatinase test, which is positive for Clostridium tetani.
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Flashcard 43
Q: What is the preferred medium for culturing Clostridium perfringens?
A: Egg Yolk Agar (EYA), where it shows positive lecithinase activity, indicated by an opaque zone around the colonies.
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Flashcard 44
Q: What special staining method is used to visualize Bacillus anthracis spores?
A: The M'Fadyean's stain, used for identifying Bacillus anthracis in tissue samples and cultures.
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Flashcard 45
Q: What clinical condition is caused by Clostridium botulinum in infants?
A: Infant botulism, also known as "floppy baby syndrome," caused by the growth of C. botulinum in the intestines of infants.
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Flashcard 46
Q: What is the appearance of Clostridium tetani on culture media?
A: Initially alpha-hemolytic, C. tetani becomes beta-hemolytic on blood agar plates (BAP) as it grows.
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Flashcard 47
Q: How is Clostridium difficile typically treated in severe cases of infection?
A: Metronidazole or vancomycin is often used to treat severe Clostridium difficile infections, especially in cases of pseudomembranous colitis.
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Flashcard 48
Q: What condition is caused by Clostridium botulinum through foodborne infection?
A: Botulism, which occurs after consuming food contaminated with botulinum toxin, particularly improperly canned foods.
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