Microbiology Chapter 15

Front 1

Pathogenicity

Back 1

Ability to cause disease in a host

Front 2

Virulence

Back 2

Degree of pathogenicity

Front 3

Portals of Entry

Back 3

Mucous membranes (respiratory tract, gastroinestinal tract, genitourinary tract, conjunctiva) Skin, Parenteral route (break in skin)

Front 4

Skin

Back 4

Largest organ of the body
good barrier
some microorganisms can use hair follicles & sweat glands ducts as portals of entry

Front 5

Mucous Memebranes

Back 5

Most common portal of entry for microogranisms

Front 6

Respiratory Tract

Back 6

lysozyme. mucus and ciliary escalator

Front 7

Gastrointestinal Tract

Back 7

HCl and digestive enzymes

Front 8

Genitourinary Tract

Back 8

Urine flow and basic pH

Front 9

Conjunctiva of the eye

Back 9

tears and lysozyme

Front 10

Lysozyme

Back 10

damages gram postive cell wall

Front 11

Parenterally

Back 11

microorganisms introduced beneath skin and mucous membranes by punctures, bites, cuts, abrasions, injections and wounds

break in skin

Front 12

Variolation

Back 12

small pox vaccine introduces infected tissue into skin of a healthy individual. Recipent usually developes mild disease, recovered and immuned.

Front 13

LD50

Back 13

Lethal dose 50% is dose or number of microbes that kills 50% of exposed hosts

Front 14

ID50

Back 14

infective dose 50% is number of microbes that produces diseae in 50% of exposed hosts

Front 15

Adherence

Back 15

Surface molecules on a pathogen called adhesions or ligands bind specifically to complementary surface receptors on cells of certain host tissues

Adherence or attachement of microbial adhesin to host cell receptor is required for infection

Front 16

Adherence and HIV

Back 16

CD4 receptor
Adhersion = HIV gp120, receptor = host T cell CD4

Front 17

Glycocalyx

Penetration of Host Defenses

Back 17

capsule increases virulence by inhibiting phagocytosis

Front 18

Cell Wall Components

Penetration of Host Defenses

Back 18

M protein of the Strepococcus pyogenes cell wall and frimbrae.
Enhances adherence to epithelial cells and inhibits phagocytosis

Front 19

Enzymes

Penetration of Host Defenses

Back 19

excreted by microorganism that breakdown host defenses

Front 20

Leukocidins

Back 20

Kill WBCs

(staphylococcus & streptococcus)

Front 21

Hemolysins

Back 21

Lyse RBCs

(staphylococcus & streptococcus)

Front 22

Coagulases

Back 22

clot fibrinogen to form fibrin clot

(staphylococcus - boil lesion)

Front 23

Kinases

Back 23

Dissolve blood clots

(streptococcus)
Streptokinase

Front 24

Hyaluronidase

Back 24

Breaks down hyaluronic acid, matrix that holds connective tissue together

(streptococcus - necrotizing fascaiitis)

Front 25

Collagenase

Back 25

Breaks down collagen, connective tissue of muscles

(clostridium - has gangrene)

Front 26

DNAses

Back 26

Breaks down DNA in pus making less viscous

Front 27

Microbial Damage

Back 27

Direct damage
Toxins

Front 28

Direct Damage

Back 28

Growth and replication of pathogen in cell is harmful

Front 29

Toxins

Back 29

Exotoxins and Endotoxins

Front 30

Exotoxins

Back 30

proteins produced mostly by Gram (+) POSTIVE cells and excreted into medium.

cytotoxic, neurotoxic and enterotoxic

Front 31

Endotoxins

Back 31

Lipid A component of LPS layer of cell wall of Gram NEGATIVE cells.

chills, fever, weakness, achiness, shock and death


endotoxins are released whtn the cell dies

Front 32

Antitoxins

Back 32

antibodies produced by host immune system that specifically binds to and inactivates a toxin

antibodiy binds to antitoxin, it's specific

Front 33

Toxoid

Back 33

exotoxins inactivated by heat or chemical treatment that are used as vaccines to stimulate formation of antitoxins

(tetanus toxoid used as tentus vaccine)

deactivates toxins in a vaccine

Front 34

Tetanus

Back 34

neurotoxin

exotoxin

Front 35

Lipid A Endotoxin

Back 35

Lipid A of LPS of Gram negative cell walls cause fever, shock, death