15.2/17.3 Flashcards
What are Koch’s Postulates?
Set of standards that must be met to demonstrate that X pathogen causes X disease
What is step 1 of Koch’s Postulates
The suspected pathogen must be found in every case of disease and not be found in healthy individuals
What is step 2 of Koch’s postulates?
The suspected pathogen can be isolated and grown in pure culture
What is step 3 of Koch’s postulates?
A healthy test subject infected with the suspected pathogen must develop the same signs and symptoms of disease as seen in postulate 1
What is step 4 of Koch’s postulates?
The pathogen must be re-isolated from the new host and must be identical to the pathogen from postulate 2
What are Koch’s wrong assumptions?
- Pathogens are found only in diseased individuals
- All subjects are equally susceptible to infection
- All pathogens can be grown in culture
What does molecular Koch’s Postulates identify instead of pathogen?
gene
What is the first step of Molecular Koch’s Postulates?
The phenotype should be associated only with pathogenic strains of a species
What is the second step of Molecular Koch’s Postulates?
Inactivation of the suspected gene(s) associated with pathogenicity should result in a measurable loss of pathogenicity
What is the third step of Molecular Koch’s Postulates?
Reversion of the inactive gene should restore the disease phenotype
What are the few limitations of Molecular Koch’s Postulates?
- Genetic manipulation of some organisms isn’t possible with current techniques
- Some diseases do not have suitable animal models
Ability of a pathogen to cause disease?
Pathogenicity
Degree of pathogenicity?
Virulence
What is ID50? Related to Morbidity or Mortality?
Median Infectious dose - no. of pathogens required to infect 50% of those inoculated; Morbidity
What is LD50? Related to Morbidity or Mortality?
Median lethal dose - no. of pathogens required to kill 50% of those infected; Mortality
What pathogen can cause disease in a host regardless of the host’s resident microbiota or immune system?
Primary Pathogen
What pathogen can only cause disease in situations that compromise the host’s defenses?
Opportunistic pathogen
What are the 5 stages of Pathogenicity?
- Exposure to host
- Adhesion
- Invasion
- Infection
- Transmission
What are TORCH infections?
Pathogens that can cross placental barrier
What is adhesion in the stages of pathogenicity?
The capability of colonization
What are molecules/structures that bind to certain host receptors called?
Adhesins
What is a production of community glycocalyx called?
Biofilm
What is it called when colonization is established in the stages of pathogenicity?
Invasion
T/F Virulence plays role in degree of invasion
T
How does intracellular pathogens invade?
Via endocytosis and evasion of host immune defenses
Which invasion mechanism have effector proteins secreted to trigger entry?
Membrane ruffling
Which invasion mechanism has surface proteins that allow for binding to the host cell?
Trojan horse approach
Multiplication leads to what stage of pathogenicity?
Infection
What type of infection is at a small area of body?
Local infection
What type of infection has a pathogen/toxin spread to a secondary location?
Focal infection
What type of infection occurs throughout the body?
Systemic
T/F Can Primary infections lead to secondary infection of different pathogen
T
Transmission to a new host through a portal of exit ensures what?
Persistence
What is the differentiation of blood cells from bone marrow stem cells called?
hematopoiesis
What are the 3 types of Granulocytes?
Neutrophils, Eosinophils, Basophils
What is the agranulocyte exception?
Natural Killer cells
Which granulocyte has 3-5 connected lobes and small, purple granules?
Neutrophils
Which granulocyte has 2-3 lobes and large, red/orange granules?
Eosinophils
Which granulocyte has 2 lobes and large, purple granules?
Basophils
What granulocyte is involved with the destruction of extracellular bacteria and produces defensins and hydrolytic enzymes?
Neutrophils
What are meshes of chromatin with AMPs to trap pathogens called?
NETs - Neutrophil extracellular traps
What granulocyte is good at protecting against protozoa and helminths and has granules that contain histamine, degradative enzymes, and major basic protein?
Eosinophils
What induces degranulation of basophils?
Activated complement cascade
What granulocyte is important in allergic reactions and inflammatory responses and has granules containing histamine and cytokines?
Basophils
What function does Mast cells have?
Similar to Basophil function
Where are Mast cells found?
Associated with blood vessels and nerves, or found close to surface structures
What are 2 main types of agranulocytes?
Lymphocytes and Monocytes
Natural killer cells and B cells/T cells fall under what type of agranulocyte?
Lymphocytes
Macrophages, dendrites, and mononuclear phagocyte systems fall under what type of agranulocyte?
Monocyte
Natural killer cells are considered to have adaptive or innate immunity?
Innate Immunity
B cells and T cells are considered to have adaptive or innate immunity?
Adaptive Immunity
What do Natural Killer Cells do?
Seek out non-self markers and express cytokines and cytotoxic molecules stored in granules to kill non-self cell
What do Natural Killer Cells specifically secrete to induce apoptosis in target cells?
Perforin and granzymes
Macrophages are specialized in ________
tissues
Dendritic cells are specialized in _________
skin and mucous membranes
Monocytes (dendritic and macrophages) are important promoters of __________ immunity
adaptive
