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Questions and Answers
What is a significant treatment for gas gangrene caused by Clostridium perfringens?
What is a significant treatment for gas gangrene caused by Clostridium perfringens?
What disease is caused by the exotoxins produced by Clostridium difficile?
What disease is caused by the exotoxins produced by Clostridium difficile?
Which organism is known to cause botulism due to its toxin?
Which organism is known to cause botulism due to its toxin?
What is the typical habitat for Clostridium botulinum?
What is the typical habitat for Clostridium botulinum?
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What preventative measure should be taken to avoid botulism?
What preventative measure should be taken to avoid botulism?
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Which of the following genera of Gram-positive bacilli are known to be spore-forming?
Which of the following genera of Gram-positive bacilli are known to be spore-forming?
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What is the primary symptom of food poisoning caused by Bacillus cereus?
What is the primary symptom of food poisoning caused by Bacillus cereus?
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Which disease is associated with Corynebacterium diphtheriae?
Which disease is associated with Corynebacterium diphtheriae?
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Which of the following Gram-positive bacilli is transmitted through inhalation of spores from animal hair?
Which of the following Gram-positive bacilli is transmitted through inhalation of spores from animal hair?
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What is the characteristic appearance of Clostridium tetani under microscopy?
What is the characteristic appearance of Clostridium tetani under microscopy?
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Which Gram-positive bacillus is commonly found in soil and is associated with cutaneous anthrax?
Which Gram-positive bacillus is commonly found in soil and is associated with cutaneous anthrax?
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What is unique about the capsule of Bacillus anthracis?
What is unique about the capsule of Bacillus anthracis?
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What is the oxygen requirement for Clostridium species?
What is the oxygen requirement for Clostridium species?
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What causes the pseudomembrane seen in the throat due to diphtheria?
What causes the pseudomembrane seen in the throat due to diphtheria?
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How is Listeria monocytogenes primarily transmitted to infants?
How is Listeria monocytogenes primarily transmitted to infants?
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What distinguishes Clostridium tetani under a microscope?
What distinguishes Clostridium tetani under a microscope?
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What is the primary preventive measure against diphtheria?
What is the primary preventive measure against diphtheria?
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Which drug is used to neutralize the tetanus toxin?
Which drug is used to neutralize the tetanus toxin?
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What type of immunity is often reduced in individuals prone to listeriosis?
What type of immunity is often reduced in individuals prone to listeriosis?
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Which of the following is NOT a disease associated with Listeria monocytogenes?
Which of the following is NOT a disease associated with Listeria monocytogenes?
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Which of the following characteristics defines Corynebacterium diphtheriae?
Which of the following characteristics defines Corynebacterium diphtheriae?
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Study Notes
Gram-Positive Bacilli Overview
- Five medically important genera: Bacillus, Clostridium, Corynebacterium, Listeria, and Gardnerella.
- Bacillus and Clostridia form spores, the rest do not.
- Bacillus are obligate aerobes, Clostridium are obligate anaerobes.
- Some have unique shapes: Actinomyces are branched, Corynebacteria are club-shaped, Clostridium tetani are drum-stick shaped, and Nocardia are branching filaments.
Bacillus cereus
- Causes food poisoning.
- Found in domestic animals, soil, and rice grains.
- Transmitted via ingestion of contaminated food, especially reheated rice.
- Produces two toxins: one similar to cholera toxin and the other similar to staphylococcal enterotoxin.
- Symptoms include nausea, vomiting, and non-bloody diarrhea.
Bacillus anthracis
- Causes anthrax.
- Three forms: cutaneous, pulmonary, and gastrointestinal.
- Found in soil.
- Transmitted by contact with infected animals, inhalation of spores from animal hair and wool.
- Cutaneous anthrax: Painless ulcer, black eschar, local edema, can lead to bacteremia and death.
- Pulmonary anthrax: Symptoms resembling influenza, progresses to hemorrhagic mediastinitis, bloody pleural effusions, septic shock, and death.
- Gastrointestinal anthrax: Vomiting, abdominal pain, and bloody diarrhea.
Corynebacterium diphtheriae
- Causes diphtheria.
- Symptoms: High fever, chills, sore throat, enlarged neck lymph nodes, greyish membrane on throat (pseudomembrane).
- Found in the human throat.
- Transmitted via respiratory droplets.
- Pseudomembrane formed due to death of mucosal epithelial cells from diphtheria toxin.
Listeria monocytogenes
- Causes meningitis and sepsis in newborns and immunocompromised individuals, and gastroenteritis.
- Found in gastrointestinal and female genital tracts, as well as animals, plants, and soil.
- Transmitted across placenta or during delivery.
- Outbreaks linked to unpasteurized milk products, e.g., cheese.
- Grows well at cold temperatures ("cold enhancement").
- Predisposing factors: Reduced cell-mediated immunity, immunologic immaturity.
Clostridium tetani
- Causes tetanus.
- Produces tetanus toxin (tetanospasmin).
- Found in soil.
- Transmitted through traumatic breaks in the skin.
- Spore-forming rods with a terminal spore, giving a "tennis racket" appearance.
Clostridium perfringens
- Causes gas gangrene and food poisoning.
- Found in soil and the human colon.
- Gas gangrene: Wound contamination with soil or feces.
- Food poisoning: Ingestion of contaminated food.
- Produces alpha toxin (lecithinase) causing gas gangrene.
Clostridium botulinum
- Causes botulism, characterized by flaccid paralysis.
- Found in soil.
- Transmitted through improperly preserved food.
- Prevention: Proper food preservation techniques, cooking home-canned food, discarding bulging cans.
Clostridium difficile
- Causes pseudomembranous colitis.
- Found in the human colon.
- Transmitted fecal-orally.
- Overgrowth occurs due to antibiotic use, leading to toxin production.
Actinomyces israelii
- Causes actinomycosis, characterized by abscesses with draining sinus tracts.
- Found in the human mouth, especially anaerobic crevices around teeth.
- Transmission: Dental disease or trauma, aspiration into lungs, retained intrauterine devices.
Nocardia asteroides
- Causes nocardiosis, especially lung and brain abscesses.
- Found in soil.
- Transmitted via airborne particles, inhaled into the lungs.
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Description
This quiz covers key concepts about gram-positive bacilli, including important genera like Bacillus, Clostridium, and Corynebacterium. It examines their shapes, spore formation, and specific pathogenic types, such as Bacillus cereus and Bacillus anthracis. Test your knowledge on their transmission methods, symptoms, and clinical significance.
