Lecture 2 Flashcards
(47 cards)
What 5 factors determine the severity of a disease?
- Inoculum size
- Strain of bacteria
- Susceptibility of host
- Threshold for disease production
- Tissue/function affected
What are 4 factors influence the strength of the immune response
- Ability to colonize
- Damage potential
- Duration of infection
- Number of pathogens
Name 8 Virulence Factors
- Adherence
- Invasion
- Capsule
- Metabolic byproducts
- Toxins (endotoxins, exotoxins and superantigen)
- Excess inflammation
7.Evasion of immune response - Resistance to antibiotics
What are the three types of bacteria?
Commensal, Opportunistic, and Virulent
What are commensal bacteria?
Bacteria that coexist with the host without causing harm
What are opportunistic bacteria?
Bacteria that normally do not cause disease but can become pathogenic under certain conditions
Give an example of an opportunistic bacterium that can become virulent.
Clostridium difficle
What is a Pathogenicity Island?
A cluster of virulence genes within the bacterial genome that enhances pathogenicity
What 4 major steps of bacterial infection
- Enter
- Colonize
- Destroy
- Evade
What are the two main types of bacterial entry into the body?
Natural openings and barrier breaches
look over slide 13,14,15
adhesion defintion
bacteria must bind to host cell surfaces
What are adhesins?
Bacterial proteins that interact with host receptors
* Commonly found on tips of fimbriae (pili)
* Also associated with bacterial surface (Ex. Lipoteichoic acid)
What is the primary component of a bacterial biofilm?
Polysaccharides
give me 4 points on bioflim production
- Primarily composed of polysaccharides
- Binds cells of a colony together
- Produced when colony number reaches a threshold
(quorum) - Protects colony from host defenses, antibiotics
* Ex. Dental plaque, medical appliances
How do invasive bacteria enter host tissues?
By destroying barriers and using effector proteins to facilitate transport
What role do effector proteins play in bacterial invasion?
Effector proteins facilitate transport
How does E. coli promote invasion?
E. coli secrete proteins that form docking station
How does Salmonella promote its uptake into host cells?
Salmonella secrete proteins that promote vesicular uptake
What type of cells do some bacteria use for transport across the intestinal barrier?
M Cells
What are two main ways bacteria cause tissue destruction?
Direct damage through metabolic byproducts and degradative enzymes, and indirect damage by triggering excessive immune responses.
Name three bacterial metabolic byproducts that contribute to tissue destruction
Acids, gases, and other toxic substances
Name three degradative enzymes involved in tissue destruction
Collagenase, hyaluronidase, and fibrinolysin
What are two ways bacteria induce cell death?
Apoptosis (programmed cell death) and lysis (cell rupture)
