CORRECT LEARNING OBJECTIVES

• Key Characteristics of Prokaryotes

  • Lack a true nucleus and membrane-bound organelles
  • Cell wall, plasma membrane, nucleoid (DNA region), flagella (for motility), pili/fimbriae (attachment), capsule (protective layer), endospores (dormant, resistant structures)
• Gram Stain Procedure


  Technique to differentiate bacteria into Gram-positive (purple) and Gram-negative (pink) based on cell wall composition
• Factors affecting Bacterial Growth

  • Nutrients
  • Temperature
  • pH
  • Oxygen
  • Water
• Bacterial Growth Curve


  1. Lag phase (adapting to new environment)

  2. Exponential (rapid growth)

  3. Stationary (growth rate equals death rate)

  4. Death (decline in population)
• Symbiont


  Organism living in symbiosis with another
• Pathogen


  Organism causing disease
• Plasmid


  Small, circular DNA molecule in bacteria
• Quorum Sensing


  Bacteria communicate and coordinate behavior based on population density
• Anaerobe


  Organism that can live without oxygen
• Bacterial Pathogenesis


  1. Adherence

  2. Invasion

  3. Colonization

  4. Damage
• Virulence Factors


  • Toxins
  • Superantigens
  • Biofilm formation
• Transfer of Virulence Factors

  1. Conjugation

  2. Transduction

  3. Transformation
• Methods for Diagnosis of Bacterial Infections

  • Microscopic observation
  • Culture and biochemical characteristics
  • Serotyping
  • Molecular techniques
• Antimicrobial Agents


  • Cell wall synthesis inhibitors
  • Protein synthesis inhibitors
  • DNA synthesis inhibitors
  • Folic acid synthesis inhibitors
• Gram-Positive Cocci


  • Staphylococcus
  • Streptococcus
• Gram-Positive Rods


  • Listeria monocytogenes
  • Bacillus anthracis
• Gram-Negative Rods


  • Escherichia coli
  • Salmonella serotypes
  • Brucella
  • Bordetella bronchiseptica
• Types of Bacterial Vaccines

  • Live attenuated
  • Inactivated
  • Subunit
  • Conjugate
• Goals of Bacterial Vaccines

  • Prevent infection
  • Reduce severity
  • Prevent transmission
• Virulence Factors


  • Toxins: Substances that can cause damage to host cells or tissues
  • Superantigens: Stimulate excessive immune responses leading to tissue damage
  • Biofilm Formation: Bacteria form a protective layer that makes them resistant to host defenses and antibiotics
• Transfer of Virulence Factors

  1. Conjugation: Direct transfer of genetic material between bacteria

  2. Transduction: Transfer of genetic material mediated by bacteriophages

  3. Transformation: Uptake of naked DNA from the environment
• Methods to Detect the Causal Agent

  • Direct Microscopic Observation: Staining techniques to visualize bacteria
  • Cultural and Biochemical Characteristics: Growth characteristics and metabolic activities in culture media
  • Serotyping: Identification based on specific antigens
  • Molecular Techniques: PCR, sequencing, etc.
• Methods to Detect the Host Immune Response

  • Serology: Detection of antibodies against specific bacterial antigens
  • Detection of Cell-Mediated Immunity: Tests to assess the cellular immune response
• Methods to Limit Microbial Growth

  • Sterilization: Complete elimination of all forms of microbial life
  • Antimicrobial Agents: Drugs that inhibit the growth of or kill microorganisms
• Classification of Antimicrobial Agents

  • Chemical Structure: Beta-lactams, aminoglycosides, quinolones, etc.
  • Mode of Action: Cell wall synthesis inhibitors, protein synthesis inhibitors, etc.
  • Spectrum of Activity: Broad-spectrum vs. narrow-spectrum
  • Type of Antimicrobial Activity: Bactericidal vs. bacteriostatic
• Antimicrobial Susceptibility Testing: Determines the effectiveness of antimicrobial agents against specific bacteria
• Antimicrobial Resistance: The ability of bacteria to resist the effects of antimicrobial agents, leading to treatment failure
• Gram-Positive Cocci


  • Staphylococcus: Causes skin infections, food poisoning, and more
  • Streptococcus: Causes various infections, including strep throat and pneumonia
• Gram-Positive Rods


  • Listeria monocytogenes: Causes listeriosis, a foodborne illness
  • Bacillus anthracis: Causes anthrax, a severe disease in humans and animals
• Gram-Positive Anaerobes


  • Various species of Clostridium, including C. difficile, C. tetani, and C. botulinum
• Gram-Negative Rods


  • Escherichia coli: Causes gastrointestinal infections
  • Salmonella serotypes: Cause salmonellosis, a common foodborne illness
  • Brucella: Causes brucellosis, a zoonotic disease
  • Bordetella bronchiseptica: Causes respiratory infections in various animals
• Spirochetes


  • Leptospira: Causes leptospirosis, a zoonotic disease
  • Borrelia burgdorferi: Causes Lyme disease
• Mycoplasma


  A group of bacteria that lack a cell wall and can cause various infections, including pneumonia
• Rickettsiales


  • Order of bacteria that includes various species causing diseases like typhus and Rocky Mountain spotted fever
• Toxins


  • Exotoxins: Secreted proteins that can cause damage to host cells or tissues
  • Endotoxins: Part of the outer membrane of Gram-negative bacteria that are released when the bacteria die and can cause systemic effects
• Superantigens


  Proteins that can stimulate an exaggerated immune response, leading to excessive inflammation and tissue damage
• Biofilm Formation


  Bacteria can form biofilms on surfaces, protecting them from the immune system and antibiotics
• Conjugation


  Direct transfer of genetic material (plasmids) between bacterial cells through physical contact
• Transduction


  Transfer of genetic material mediated by bacteriophages (viruses that infect bacteria)
• Transformation


  Uptake of naked DNA from the environment