Lecture 02

• Why is it important to understand infectious microorganisms globally?

  They significantly impact public health worldwide
• What strategies do bacteria use to cause disease in humans?

  They enter, survive, and damage host tissues
• What is a successful feature of Vibrio cholerae?

  It effectively causes cholera in humans
• What is colonisation in microbiology?

  Growth without harm to the host
• How is infection defined?

  Growth causing damage to the host
• What does disease refer to in microbiology?

  Notable physiological changes due to microorganisms
• What is virulence?

  The ability of a microorganism to cause disease
• What are the top three global causes of death?

  Lower respiratory infections, diarrhoeal diseases, tuberculosis
• What are the body defenses against bacteria?

  • Non-specific defenses:
  • Anatomical
  • Physiological
  • Bacteriological
  • Active (immune response):
  • Complex differentiation of "self" vs "non-self"
  • Non-specific and adaptive
• How do bacteria typically enter the body?

  Through epithelial surfaces or wounds
• What is the entry route for Vibrio cholerae?

  Through epithelial and mucosal surfaces
• What is the entry route for Yersinia pestis?

  Direct injection into the bloodstream
• What is a common entry route for Staphylococcus aureus?

  Infection of implanted materials like catheters
• What are the stages of disease progression?

  1. Entry
  2. Motility/adherence
  3. Growth
  4. Immune evasion
  5. Virulence factors
  6. Transmission
• How can infections be categorised?

  Superficial or invasive at sterile sites
• What can cause disease symptoms?

  Bacterial structures, secreted products, immune reactions
• What is endotoxin?

  A bacterial structure causing disease symptoms
• What is the role of mucinases in Vibrio cholerae?

  To degrade mucous for better adhesion
• What is biofilm formation in bacteria?

  Bacteria attach and grow into structured communities
• What are the pathogenic features of bacteria?

  • Resisting phagocytosis
  • Adhesion
  • Protein secretion (toxins, enzymes)
  • LPS (endotoxin)
• What was Dr. John Snow's contribution to cholera understanding?

  He linked cholera transmission to contaminated water
• What type of organism is Vibrio cholerae?

  Gram-negative curved rod
• What is the oxidase test used for?

  To identify bacteria with cytochrome c oxidase
• What does TMPD do in the oxidase test?

  Transfers electrons to cytochrome c oxidase
• Why is Vibrio cholerae considered a successful pathogen?

  It produces virulence factors and survives in water
• What are the methods to prevent bacterial disease?

  • Infection control measures
  • Vaccination for herd immunity
  • Appropriate antimicrobial use
  • Screening inpatients
  • Prophylactic antimicrobials
• What is the purpose of prophylactic antimicrobials?

  To prevent infection while avoiding resistance
• What is a bacillus?

  A rod-shaped bacterial or archaeal cell
• What is a capsule in microbiology?

  A layer outside some microbial cells
• What is chemotaxis?

  Movement towards attractants and away from repellents
• What is an endospore?

  A dormant, resistant spore in some bacteria
• What are fimbriae?

  Hair-like appendages aiding attachment
• What is lipopolysaccharide (LPS)?

  A component of Gram-negative bacterial outer membrane
• What is peptidoglycan?

  A component of bacterial cell walls
• What is periplasm?

  The space between plasma membrane and outer layers
• What are porins?

  Proteins forming channels in Gram-negative bacteria
• What are sex pili?

  Protein appendages for bacterial conjugation
• What is an S-layer?

  A structured layer on some bacteria's surface
• What is a slime layer?

  A diffuse, easily removed layer outside the cell wall
• What is a spirillum?

  A rigid, spiral-shaped bacterial cell