Relevance of Koch’s Postulates
Koch’s Postulates: A Set of Criteria Used To Establish a Microbe-Disease Connection
Challenges to Satisfying Koch’s Postulates
The First Postulate: Association of the Microbe with Lesions of the Disease
The Second Postulate: Isolating the Bacterium in Pure Culture
The Fourth Postulate: Reisolating the Bacterium from the Intentionally Infected Animal
Modern Alternatives To Satisfy Koch’s Postulates
Detecting the Presence of the Pathogen Only in Diseased Tissues
Eliminate the Pathogen and Prevent or Cure the Disease
Comparative Infectious Disease Causation
The Microbiota Shift Disease Problem
Koch’s Postulates and Pathogenic Microbial Communities
Keystone Pathogens and Microbial Shift Diseases
Varieties of Human-Microbe Interactions
Views of the Human-Microbe Interaction
Virulence as a Complex Phenomenon
Questions
Solving Problems in Bacterial Pathogenesis
CHAPTER 7 Mechanisms of Genetic Modification and Exchange: Role in Pathogen Evolution
Adapt or Perish
Acquiring New Virulence Traits by Horizontal Gene Transfer
Mechanisms of Genetic Change and Diversification
Spontaneous Mutation
Phase Variation
Antigenic Variation
Horizontal Gene Transfer: Mobile Genetic Elements
Natural Transformation
Conjugation: Plasmids and Transposons
Phage Transduction
Control of Horizontal Gene Transfer
Toxin-Antitoxin Systems—Retaining the Goods
Restriction-Modification Systems—Bacterial Innate Immunity from Foreign DNA
CRISPR-Cas Systems—Bacterial Adaptive Immunity from Foreign DNA
Type 6 Secretion Systems—Bacterial Defense Against Conjugation
Pathogenicity Islands and Pathogen Evolution
Properties of Pathogenicity Islands
Pathogen Evolution in Quantum Leaps
Selected Readings
Questions
Solving Problems in Bacterial Pathogenesis
CHAPTER 8 Identification of Virulence Factors: Measuring Infectivity and Virulence
How Does One Experimentally Measure Virulence and Satisfy Koch’s Postulates?
Animal Models of Infection
Human Volunteers
Nonhuman Animal Models
Measuring Bacterial Infection in Animal Models
Ethical Considerations
Animal Model Basics
Survival Curve Analysis and Biophotonic Imaging
ID50 and LD50 Values
Competition Assays
Tissue Culture and Organ Culture Models
Tissue Culture Models
Gentamicin Protection Assay for Cell Adhesion and Invasion
Plaque Assay for Intracellular Survival and Cell-to-Cell Spread
Fluorescence Microscopy Techniques for Assessing Effects of Pathogens on Host Cells
Organ Culture Models
The
