Micro Ch 15 Flashcards
What is Pathogenicity?
- the ability to cause a disease
What is virulence?
- the extent of pathogenicity
What are the three portals of entry?
- Mucous Membrane
- Skin
- Parenteral (direct into tissue)
What is M-Protein?
the adhesin present in cell wall of S. pyogenes causing strep throat and rheumatic fever
Adherane is how a disease…..
infects a tissue
What can prevent an infection?
- low stress
- general health
- good immune system
Adhesins/Ligans are…
- glycoproteins or lipoproteins present on cell wall, capsule, fimbrae, flagella
- attach to receptors on host
Receptors are…
- sugars (mannose, fructose)
What is Mycholic Acid?
the adhesin for TB or Leprosy in cell wall
What is M-Protein?
the adhesin present in cell wall of S. pyogenes causing strep
Why is M-Protein so dangerous?
- evades phagocytosis
- acid/heat resistant
What use Fimbriae as an adhesin?
- e-coli
- gastroenteritis
- UTI
What are Exotoxins?
- part of metabolism
- used in Gram+ve and Gram-ve
- proteins
- able to circulate
What are 4 examples of Exoenzymes?
- Coagulase
- Kinase
- Hyaluronidase
- Collagenase
What is coagulase?
- used in S. aureus
- causes blood clots
- cause MRSA
What is Kinase?
- breaks fibrin clot
- used nu S. pyogenes
What is Hyaluronidase?
- breaks hyaluronic acid used in connective tissue and muscle
- used by S. pyogenes (necrotizing fasciitis)
- used by C. perfunges ( gangrines)
- blackens skin and leads to a quick spread through body
What is Collaginase?
- dissolves collagen
- C. perfringes (gangrenes)
What is a toxoid?
neutralized exotoxin used in vaccines
What are Endotoxins?
- Lipid A
- from LPS regionin outer membrane of gram-ve bacteria
- cause fever leading to septic shock
- cannot be neutralized
- can cause nausea, vomiting, diarrhea, clots, miscarriage
3 Types of Exotoxins
- “Classic”
- Membrane-Disrupting
- Superantigens
Describe Classic Exotoxins
- always has two classic polypeptide chains (A&B)
- A- active part
- B- binding
What are four examples of Classic Exotoxins?
- Diptheriotoxin
- binds to resp tract
- shuts down protein synthesis
- suffocates host
- Tetanospasmin
- binds to neurons
- inhibits GABA inhibiting relaxation causign spasms
- Botulinum
- found in canned foods
- neurotoxin
- inhibits release of ACh
- flaccid paralysis
- death
- Vibriotoxin
- endotoxin
- triggers cyclic AMP
- causes rice water stools
- causes severe dehydration
- facilitates shock
What are three examples of Membrane Disrupting endotoxins?
- Blood Agar
- hemolysin disrupts membranes of RBC
- S. Pyogenes
- Leukocidins
- WBC
- S. Pyogenes
