damage and pathophysiology

• What is the first toxin characterized?

  Diphtheria toxin
• What is the main aim of bacterial toxins?

  To interrupt energy or protein manufacture
• What type of toxins work at a specific site in the body?

  Site specific toxins
• What do neurotoxins affect in the body?

  Neurones of the gut
• What toxin causes flaccid paralysis?

  Botulinum toxin
• What is the effect of cholera toxin?

  It causes massive fluid efflux
• What are membrane damaging toxins known to cause?

  Lysis by disrupting membrane integrity
• What do leukocidins target?

  White blood cells
• What is the role of super antigen toxins?

  They activate the immune system non-specifically
• What is the toxic moiety of endotoxin?

  Lipid A
• What is the effect of 1 ng of endotoxin introduced intravenously?

  Temperature increases by more than 1°C
• What does the α toxin of Clostridium perfringens do?

  It hydrolyzes phospholipids
• How does Clostridium tetani cause rigid paralysis?

  By blocking inhibitory neurotransmitter release
• What is the causative agent of gangrene?

  Clostridium perfringens
• What type of paralysis does botulinum toxin induce?

  Flaccid paralysis
• What is the primary effect of cholera toxin on the intestinal mucosa?

  Massive efflux of fluid and electrolytes
• How does cholera toxin affect cAMP levels?

  It increases cAMP levels significantly
• What are the two main categories of microbial toxins?

  Exotoxins and endotoxins
• What is the function of A-B toxins?

  To act intracellularly on specific mechanisms
• What is the role of the B subunit in A-B toxins?

  It allows entry of the A subunit
• What does diphtheria toxin do to protein synthesis?

  It stops protein synthesis
• How does the α toxin of Clostridium perfringens compromise cell integrity?

  By cleaving membrane phospholipids
• What are the classes of toxins discussed in the material?

  • A-B toxins
  • Site specific toxins
  • Neurotoxins
  • Enterotoxins
  • Cytotoxins
  • Membrane damaging toxins
• What are the roles of secreted virulence factors?

  • Promote spread of infection
  • Destroy host tissues
  • Evade immune responses
• What is the significance of endotoxins in Gram-negative bacteria?

  • Major component of outer membrane
  • Induces endotoxic shock
  • Plays a role in systemic infections
• What are the consequences of tetanus toxin action?

  • Continuous muscle contraction
  • Rigid paralysis
  • Potential respiratory failure
• What are the consequences of botulinum toxin action?

  • Flaccid paralysis
  • Respiratory and cardiac failure
  • Potential medical uses
• What are the effects of cholera toxin on the intestinal mucosa?

  • Non-invasive colonization
  • Massive fluid and electrolyte loss
  • Risk of fatal dehydration
• What are the main components of the immune response affected by super antigen toxins?

  • Non-specific activation of T cells
  • Overproduction of cytokines
  • Damage to blood vessels and organs
• What are the roles of degradative enzymes in microbial invasion?

  • Promote spread of infection
  • Destroy host tissue structure
  • Facilitate penetration to deeper tissues
• What are the effects of leukocidins and hemolysins?

  • Kill white blood cells
  • Burst red blood cells
  • Contribute to tissue damage
• What is the significance of the A subunit in A-B toxins?

  • Acts intracellularly
  • Modifies specific proteins
  • Responsible for toxic effects
• What is the role of the B subunit in A-B toxins?

  • Facilitates entry of the A subunit
  • Determines cell tropism
  • Induces endocytosis
• What is the mechanism of action of diphtheria toxin?

  • Internalized through endocytosis
  • Modifies protein essential for synthesis
  • Results in cell death
• What are the consequences of endotoxin exposure?

  • Fever and shock
  • Activation of immune responses
  • Potential for multi-organ failure
• What is the significance of the α toxin in gangrene?

  • Causes extensive tissue destruction
  • Difficult to treat due to poor blood flow
  • Contributes to foul odor production