Introduction; Classification of bacteria

• What is the focus of medical microbiology?

  Study of micro-organisms causing human infections
• Why do most micro-organisms require magnification?

  They are small, often less than 0.1 mm
• What are the main groups of micro-organisms?

  Bacteria, fungi, viruses, parasites
• What are the two groups of micro-organisms based on cellular structure?

  • Eukaryotic organisms;
  • Well-developed cells with organelles
  • Includes protozoa and fungi

  
  

  • Prokaryotic organisms;
  • Primitive cells, unicellular, no nucleus
  • Includes bacteria
• Who is referred to as the Great founding father of Medical Microbiology?

  Dr. R. Koch
• What did Koch establish regarding specific diseases?

  He identified bacterial causative agents
• What are Koch's postulates used for?

  To prove an organism causes a specific illness
• What are the four criteria of Koch's postulates?

  1. Organism must be found in all disease cases
  2. Organism must be isolated in pure culture
  3. Inoculation should reproduce the disease
  4. Organism must be re-isolated from lesions
• What is the significance of Gram's stain in bacteriology?

  It helps in identifying bacteria types
• What are some developments in antibacterial agents in the 20th century?

  • Synthetic arsenical compound for syphilis
  • Discovery and development of penicillin
  • Discovery and development of sulphonamides
• How has technology advanced the study of micro-organisms?

  It improved understanding of DNA and functions
• What are some discoveries based on molecular biology?

  1. Classifying microorganisms by DNA
  2. Genetic properties in infection pathogenesis
  3. Laboratory tests for infection diagnosis
  4. Antimicrobial resistance detection techniques
• What is microscopy used for in medical bacteriology?

  Visualization of micro-organisms
• What are the types of microscopes used in bacteriology?

  • Light microscope
  • Phase contrast microscope
  • Dark field microscope
  • Fluorescence microscope
  • Electron microscope
• What is the purpose of staining in bacteriology?

  To make bacteria more visible and identifiable
• What are the types of staining techniques in bacteriology?

  • Simple staining
  • Negative staining
  • Differential staining
  • Fluorescence staining
• What is the role of culture media in bacteriology?

  To grow and isolate bacteria
• What are the types of artificial culture media?

  • Simple media
  • Selective media
• What is the function of selective media?

  Isolate specific organisms from specimens
• What does selective media contain to inhibit other bacteria?

  Chemicals or antimicrobial agents
• What are colonies on semi-solid media?

  Clusters arising from a single bacterial cell
• What do colonies on media indicate?

  Specific features for the type of bacterium
• What are the types of artificial culture media?

  • Simple media
  • Selective media
  • Enriched media
  • Enrichment media
  • Transport media
  • Indicator media
• What is the purpose of simple media?

  For general use and growth of many bacteria
• What do simple media contain?

  Peptone, polypeptides, and amino acids
• What is selective media used for?

  Isolation of a specific organism from specimens
• What do selective media contain?

  Chemicals or antimicrobial agents
• How do selective media function?

  Inhibit growth of other bacteria while allowing specific growth
• What is an example of selective media?

  Thayer-Martin medium
• What is enriched media designed for?

  Isolation of fastidious bacteria requiring special nutrients
• What does blood agar contain?

  10% blood
• What are enrichment media used for?

  Favor multiplication of a specific organism
• What is an example of enrichment media?

  Alkaline peptone water
• What is the purpose of transport media?

  Protect delicate bacteria during transportation
• What is an example of transport media?

  Stuart's transport medium
• What do indicator media contain?

  Fermentable carbohydrates and chemical indicators
• What is the function of indicator media?

  Detect organisms through color change due to pH
• What is an example of indicator media?

  MacConkey's medium
• What are the atmospheric requirements for bacterial growth?

  Varies among bacteria associated with human infections
• What is the optimum growth temperature for most bacteria?

  35 to 37 degrees centigrade