23 Questions
Which of the following is a characteristic of Clostridium species?
Possess peritrichous flagella
Which Clostridium species causes gas gangrene?
Clostridium perfringens
What is the natural habitat of most Clostridium species?
Intestinal tract or soil as saprophytes
Which Clostridium species causes tetanus?
Clostridium tetani
What triggers the liberation of toxin produced by Clostridium botulinum into the environment?
Bacterial autolysis
Which Clostridium species is responsible for causing botulism in infants?
Clostridium botulinum
How is wound botulism acquired?
Traumatic implantation of spores (drug users)
What is a symptom specific to infant botulism?
Respiratory arrest
Which diagnostic method is used for suspected infant botulism?
Toxin demonstrated in stool
What is the treatment approach for wound botulism?
Trivalent antitoxin
How do drug users commonly acquire wound botulism?
Traumatic implantation of spores
Which type of botulism involves the ingestion of preformed toxin?
Adults (foodborne) botulism
What is the most common source of toxin contamination in adults' botulism?
Vacuum packed or canned alkaline foods
How does the botulinum toxin act in the body?
By inhibiting acetylcholine release at synapses and neuromuscular junctions
Which symptom typically occurs in adults with botulism 18-24 hours after ingestion of the toxic food?
Visual disturbances and incoordination of eye muscles
What is a notable feature about the consciousness level of patients with botulism before death?
They are fully conscious until shortly after recovery
What is a common characteristic in the progression of symptoms in adults with botulism?
Progressive signs of bulbar paralysis leading to death
What is the lethal dose for a human of toxin A, B, and E?
1-2 mg/kg
How are the heavy and light chains of toxin A, B, and E linked?
By disulfide bonds
Which type of neurons do botulinum toxin bind to?
Motor neurons
What process is inhibited by proteolysis of target SNARE proteins in neurons by botulinum toxin?
Neurotransmitter release
What is the main cause of pathogenicity of the organism that produces botulinum toxin?
Toxin production
At what temperature can toxin A, B, and E be destroyed by heating for 20 minutes?
100°C
Study Notes
Clostridium Species Characteristics
- Large anaerobic, gram-positive, motile rods with peritrichous flagella
- Form endospores, which are usually wider than the diameter of the rods
- Spores can be centrally, subterminally, or terminally placed
Medically Important Species of Clostridium
- Clostridium tetani: causes tetanus
- Clostridium botulinum: causes botulism
- Clostridium perfringens: causes gas gangrene or food poisoning
- Clostridium difficile: causes diseases
Clostridium botulinum
- Found in soil and occasionally in animal feces
- Causes botulism, infant botulism, and rarely wound infection
- Toxin produced during growth and autolysis of the bacteria
- Laboratory diagnosis: toxin demonstrated in serum or suspected food
Types of Botulism
- Adults' botulism (foodborne): preformed toxin ingested through contaminated food or water
- Wound botulism: traumatic implantation of spores, in vivo production of toxin
- Infant botulism: spores ingested through household dust, honey, or other sources, toxin produced in the gut
Symptoms of Botulism
- Constipation, limpness/flaccid paralysis (reversible), diplopia, dysphagia, weak feeding/crying, respiratory arrest
- Visual disturbances, incoordination of eye muscles, double vision, inability to swallow, speech difficulty
- Descending flaccid paralysis, no fever, patient remains fully conscious until shortly before death
Characteristics of Botulinum Toxin
- Seven antigenic varieties of toxin (A-G) produced
- Types A, B, E, and F are causes of human illness
- Toxin A, B, E have the following characteristics:
- Highly toxic, lethal dose for a human is about 1-2 μg/kg
- Destroyed by heating for 20 minutes at 100°C
- Neurotoxic protein, made of heavy and light chains linked by disulfide bonds
- Botox is a commercial preparation of exotoxin A used to remove wrinkles
Action of Botulinum Toxin
- Absorbed from the gut, binds to receptors of presynaptic membranes of motor neurons of the peripheral nervous system and cranial nerves
- Proteolysis of the target SNARE proteins in the neurons, inhibits the release of acetylcholine at the synapse and neuromuscular junction
- Results in lack of muscle contraction and flaccid paralysis
This quiz covers medically important species of Clostridium including Clostridium tetani, Clostridium botulinum, and Clostridium perfringens. Learn about their characteristics, habitats, and associated diseases in this quiz by Dr. Majida Malik Meteab Alshammari. Part 1 of the series.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
