virulence factors

•Streptococcus pneumoniae produces____

IgA protease

Grow intracellularly •Escape the phagosome:

ListeriaandRickettsia.

-S. pyogenes produces ___ to Prevent phagocytosis

M protein

Diphtheria toxin: mode of action

Same as P. aeruginosa (pseudomonas) Exotoxin A ADP-ribosyl transferase Inactivates elongation factor 2 Inhibits host protein synthesis

-S. pneumoniae, H. influenzae, and K. pneumoniae, produce a ___ to Prevent phagocytosis

capsule

Exotoxins Preformed toxins:

food poisoning, ex. S. aureus

Exotoxins Hemolysins

•: break down red blood cells -Example: Streptococcus pyogenes (Beta) •Strep and staph aureous is Beta hemolytic

Clostridium tetani

•Blocks the release of inhibitory neurotransmitters (glycine and GABA) across the synaptic cleft. •Constant stimulation by acetylcholine, resulting in spastic paralysis.

Clostridium botulinum

•Botulinum toxin binds to presynaptic nerve terminal •Receptor binding is irreversible -Prevents presynaptic acetylcholine release -Results in FLACCID paralysis and skeletal muscle weakness

Endotoxin:

•Lipopolysaccharide, LPS -Attached to bacterial cell (All gram negativerods)

Endotoxin

•Only in Gram negative bacteria •Growing cells continually release cells small amounts of LPS.

Staphylococcus aureus produce ___

•coagulase •Coagulates fibrinogen forming abscesses

Exotoxins Cytotoxins

•destroy host cells -Example: Clostridium perfringens phospholipase C •

Pseudomonas produces ___

•elastase -Breaks down elastin in skin and connective tissue -

Streptococcus produces ___

•hyaluronidase -Breaks down the hyaluronic acid

Exotoxins Neurotoxins

•interfere with neural transmission Example:Clostridium tetanitetanus toxin

Grow intracellularly •Prevent phagosome/lysosome fusion:

- Mycobacterium

Antigenic variation:

- Neisseria gonorrhoeae

Exotoxins •Enterotoxins

-Example: Vibrio cholerae cholera toxin •GI tract ie. Vomiting diarrhea

Grow intracellularly •Break down H2O2:

-Staphylococci produce catalase

Siderophores

-lactoferrin, transferrin, ferritin, or hemin

•Streptococcus pyogenes:

C5a protease

•LPS binds to __ and ___ on monocytes and macrophages

CD14 and toll like receptor 4 (TLR4) on monocytes and macrophages -Induces IL-1 and TNFα production

Phospholipases

Clostridium perfringens phospholipase

Superantigen :Gram positive cocci Streptococcus pyogenes: Streptococcal pyrogenic exotoxin A

Streptococcal pyrogenic exotoxin A

Pore-forming exotoxin

Streptococcus pyogenes Streptolysin O-creates a pore and destroys cell

Superantigen :Gram positive cocci Staphylococcus aureus:

TSST 1

Cholera toxin

irreversibly activates the Gs regulatory protein ¯ activates adenylate cyclase ¯ causing cAMP concentration to rise ¯ triggering the cell to pump Cl- and water into the intestinal lumen ¯ causing diarrhea

-Staphylococcus & Streptococcus produce ___ to destroy leukocytes and macrophages

leukocidins