Pathogensis Model Flashcards
What are the characteristics of Corynebacterium Diptheriae?
- gram positive
- club shaped rods
- non motile
- non sporing
- aerobic
- Strict pathogen (obligate parasite:typically causes disease when present)
Where does Corynebactirum Diptheriae colonize on the body?
-nasopharynx/ skin
What are the virulence factors of Corynebacterium Diptheriae?
- fimbraie (attachment)
- A-B exotoxin (binds to human cells, catalyst enzyme)
Which organs/tissues can be damaged by Corynebacterium Diptheriae?
-throat, heart, kidney, brain
What is fibro-fatty infiltration?
-when dead cells get replaced by scar tissue
Explain what the A:B toxin is
- A-chain enzyme: stops eukaryotic translation(protein synthesis)=cell dies
- B-chain enzyme: binds heparin-binding epidermal growth factor found on many cells
How is Corynebacterium Diptheriae prevented?
-use of vaccines; although, does not prevent carriage
How do bacteriophages relate to Corynebacterium and Cutaneous Diptheriae?
-Bacteriophages can sometimes infect a bacterial cell, and then the DNA from the bacteriophage infects into the bacterial cells chromosomes
What does Diptheria toxin (DTx) do when it enters its target cell?
-toxin genes are carried to bacteria by Beta-Phage, a virus (bacteriophage) which infects Corynebacterium.
Diptheria Toxin attacks what organs?
- heart (cardiotoxicity, myocarditis)
- kidneys (nephrotoxicity)
- brain (neurotoxicity)
How does the Diptheria vaccine work?
-the vaccine pre-educates the immune system, and equips the adaptive immune system to fight pathogens pre-infection
What is the difference between the Diptheria vaccine vs antitoxin?
- vaccines stimulate antibody production (long term)
- antitoxins are pre made antibodies that neutralize toxins when injected (short term)
What is the difference between Cutaneous Diptheriae vs Corynebacterium Diptheriae
- Cutaneous Diptheriae
- wound/skin lesion infection
- slow healing ulcer
- toxin stays local, damage limited
- Corynebacterium Diptheriae
- nasopharynx/ skin infection
- transmitted through droplets, nasal secretion
Why doesn’t the Diptheria vaccine prevent people from carrying. Corynebacterium diptheriae
-a toxoid isn’t directly injecting the antibodies, its stimulating antibody production
A true/strict pathogen need to have what criteria? (2)
- be an obligate parasite: causes disease when present in/on human
- a specialist on humans
What is a facultative parasite?
- life cycle does not have to damage host
- can switch to becoming a parasite when on/in a person
What are commensalism opportunists (pathogen)?
-normal micro flora that have been displaced and now cause disease
Where is staphylococcus epidermidis found?
- normally found on the surface of the skin
Describe the structure of Staphylococcus epidermidis. What type of pathogen is this?
- Bacterial
- gram positive cocci
What are 2 diseases caused by staph. epi.?
- furuncle (skin infection)
- infective endocarditis (destroys heart valves)
Name 7 virulence factors of S. Epidermidis
- exopolymers (capsule, biofilm)
- adhesions (proteins attach)
- staphyloferrins ( iron siderophores)
- complement (c5) protease: digests immune system proteins called ‘complement’
- cytolosins:increase inflammation by stimulating neutrophils;also cause cell lysis
- antimicrobial protein (AMP) protease
- antibiotic resistant strains common
What are the function of heart valves?
-provide a one way flow of blood so there wouldn’t be a back flow
What is an endocardium? Endocarditis?
- Endocardium: the lining of the hollow parts of the heart, where the blood makes contact with the blood
- Endocarditis: when that lining becomes imflammed including the valves
How is the overall pathogenicity of S. Epidermidis? What factors make it more likely to develop a serious infection?
-Very rare; Only becomes an infection under the right conditions
Weakened immune system
Summarize the complement system of proteins
-is a system of plasma proteins that can be activated directly by pathogens or indirectly by pathogen-bound antibody, leading to a cascade of reactions that occurs on the surface of pathogens and generates active components with various effector functions
What is an environmental opportunist? Name one example
-pathogens that have the ability to grow in the outside host environment and invade their host in favorable conditions
Ex. Pseudomonas aeruginosa
Where are 3 places you might come in contact with P. Aeruginosa?
- normally found in soil
- drain of a sink
- hot tub (inadequately treated with chlorine)
Describe the structure of P. Aeruginosa. What kind of pathogen is it?
- bacterial pathogen
- gram negative rod
- has flagella
- does not do photosynthesis
What color does P. Aeruginosa appear when growing in a culture? What makes it turn this color?
- greenish color (not a photosynthesis pigment)
- the pigment increases inflammation, and is called pyocyanin (pho=pus, cyan=bluish color)
Describe 2 ways that long, dense LPS chains affect the ability of P. Aeruginosa to cause disease
- good at establishing biofilm
- can resist many disinfectants
- resist attacks from the complement system
List 5 virulence factors of P. Aeruginosa
- biofilm
- pyocyanin pigment (increases inflammation_
- pillis/fimbriae (attachment)
- neurominidase enzyme (enhances binding of fimbriae)
- LPS (resist attacks from complement system)
Name 6 anatomical locations where P. Aeruginosa commonly causes infections
- ear (swimmers ear; outer ear canal infection)
- hair follicles (hot tub folliculitis)
- skin (would and burn infections)
- bladder (urinary tract infections)
- lining of the heart (heart damage)
- lungs (lung infection)
What is zoonosis?
-a disease which can be transmitted to humans from animals
Ex. Rabies
What is another name for a neuron? What is its function?
- nerve cells
- receive incoming signals and sends outgoing signals to target cells
What is the name of the narrow gap found between neurons?
-synapse
At which point of a rabies infection can the immune system possibly intercept the virus?
- the synapse before it reaches into the CNS, 10 day period
- treatment: post exposure prophylaxis
What does the post exposure prophylaxis treatment consist of?
- Rabies vaccine (active immunization): stimulate patient to make their antibodies to bind rabies virions
- rabies immunoglobulin (passive immunization): pre-formed antibodies that bind rabies virions
Based on the lecture material, what is an example of a commensalism opportunist, zoonotic pathogen, strict/true pathogen, and a environmental opportunist?
- Commensal Opportunist: Staphylococcus epidermidis
- zoonotic pathogen: rabies virus
- strict/true pathogen: Corynebacterium diptheriae
- environmental opportunist: Pseudomonas aeruginosa
