PORTALS OF ENTRY

PORTALS OF ENTRY - coagulates blood (this same enzyme is...

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PORTALS OF ENTRY: Skin Mucous membranes (Respiratory, GI, STD's) We mentioned that pathogens must: 1. Enter the host 2. Attach to host tissues 3 Damage the host 4. Grow and multiply withing the host 5. (In the case of a communicable disease---escape the host) Lets look at the above in a bit more detail: A. Skin: parenteral route (inoculation), rusty nail, burns, all provide entry. Sex and inhalation or ingestion provide mucous membranes to a pathogen evolved to take advantage of these sites. Bacterial Pathogens have proteins called "adhesins" or ligands which promote attachment. M protein of streptococcus aids attachement and evasion of host defenses. Bacterial Enzymes that help it infect: 1. Leucocidins: Kills phagocytes, WBC's, 2. Hemolysins: Lyse RBC's also some WBC's to disrupt area of infection. 3. Coagulase: Staphylococcus aureus
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Unformatted text preview: coagulates blood (this same enzyme is what activates the Staph Latex Test in lab). Clots can wall off growing organism from blood and phagocytes, although it limits the spread of the organism. 4. Kinases: Streptokinase a good example. These break up clots to allow for spread of the organism. Streptokinase used medically to dissolve coronary clots in a coronary attack. 5. Hyaluronidase: Dissoves cellular cement-- responsible for blackening of wounds as in gangrene infections. 6. Collagenase: Breaks down collagen in connective tissue. Gelatin extracted from collagen. 7. Sideophores: scavage iron out of body fluids. 8. Invasins: These enzymes can act on actin protein to rearrange the cellular skeleton so that the pathogen can penetrate cells (Salmonella can do this)....
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This note was uploaded on 01/23/2012 for the course MCB MCB2010 taught by Professor Smith during the Fall '09 term at Broward College.

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