Chapter 15 - Microbial Mechanism

Question 1

________ is the ability of a microbe/pathogen to cause disease in a host.

Answer 1

Pathogenicity

Question 2

______ is the enhanced ability of a pathogen to cause infection.

Answer 2

Virulence

Question 3

_______ is the characteristic or trait of the pathogen that makes it harmful. This can be capsules, toxins, antigenic variation, etc.

Answer 3

Virulence Factor

Question 4

________ are the different ways by which a microbe can cause an infectious disease.

Answer 4

Mechanisms of Pathogenicity

Question 5

_______ are non-oral entry, pathogens can be directly deposited into tissue or bloodstream, and typically involve an injection into a blood vessel.

Answer 5

Parenteral route

Question 6

______ is the number of pathogens required to make 50% of the population sick. _____ measures the virulence of a microbe and infectious pathogens have varying values.

Answer 6

ID50 (Infectious Dose 50)

Question 7

Low ID50 is an indicator of _______.

Answer 7

High infectiousness -> very virulent/dangerous

Question 8

High ID50 is an indicator of ______.

Answer 8

Low infectiousness -> low virulent/dangerous

Question 9

______ is the amount of toxin required to kill 50% of the population and measures the potency of a toxin. Toxigenic pathogens have varying values.

Answer 9

LD50 (Lethal Dose 50)

Question 10

Low LD50 means _______.

Answer 10

High lethality and very toxic.

Question 11

High LD50 means _____.

Answer 11

low lethality/ not very toxic.

Question 12

_______ is the ability of pathogens to attach to host tissue/cells.

Answer 12

Adherence (adhesion/attachment)

Question 13

______ are substances on the pathogen that bind to receptors on the host cell.

Answer 13

Bacterial Adhesins (ligands)

Question 14

______ are found on Streptococcus mutans.

Answer 14

Capsules

Question 15

_______ are found on E. coli O157:H7.

Answer 15

Fimbriae

Question 16

______ are found in the cell wall of Streptococcus pyogenes.

Answer 16

M proteins

Question 17

______ can be found in the cell wall of Neisseria gonorrhaea.

Answer 17

Opa proteins

Question 18

_________ are found on Treponema pallidum.

Answer 18

Hooks

Question 19

_________ helps form blood clots, which stop blood flow, and host defenses cannot reach the bacterium. Bacteria can also surround themselves inside a clot.

Answer 19

Coagulase

Question 19

_______ breaks down blood clots surrounding the bacterium, which allows the bacterium to spread freely throughout the body.

Answer 19

Kinase

Question 20

_______ breaks down hyaluronic acid in connective tissue.

Answer 20

Hyaluronidase

Question 21

_______ breaks down collagen in connective tissue.

Answer 21

Collagenase

Question 22

________ destroys IgA.

Answer 22

IgA Protease

Question 23

______ are poisonous substances produced by pathogens that can produce fever, cardiovascular problems, diarrhea, and shock.

Answer 23

Toxin

Question 24

_______ is the ability of a pathogen to produce a toxin.

Answer 24

Toxigenicity

Question 25

______ is the presence of toxins in the bloodstream.

Answer 25

Toxemia

Question 26

______ is a chemically modified toxin which is no longer toxic. ______ is non-toxic toxin that stimulates the immune system to make antibodies.

Answer 26

toxoid

Question 27

______ is an antibody against a toxin (NOT towards the bacteria)

Answer 27

Antitoxin

Question 28

Toxin production involves bacterial _____ that carry genes for toxins.

Answer 28

Plasmids

Question 29

________ act as an antigen that triggers an immune response to produce Ab’s. An example of ______ is toxin.

Answer 29

Immunogen

Question 30

A _______ immunogen is a good stimulator of immune response, meaning that antibodies are made which result in no fever. An example of _____ Immunogen would be protein toxins.

Answer 30

Strong

Question 31

A ______ immunogen is a poor stimulator of the immune response, meaning no antibodies are made, resulting in a fever. An example of ________ immunogens would be lipid and polysaccharide toxins.

Answer 31

Weak

Question 32

______ are secreted by living cells; mostly gram-positive bacteria, some gram-negative bacteria, and do not usually have a fever

Answer 32

Exotoxins

Question 33

_____ are part of the dying bacterial cell wall, are secreted by gram-negative bacteria only, and are lipid portions of the LPS that break off and result in fever.

Answer 33

Endotoxins

Question 34

______ are composed of proteins, are highly toxic, have a low LD50, do not induce fever, and are neutralized by antitoxin.

Answer 34

Exotoxins

Question 35

______ are composed of lipids, have a high LD50, low toxicity, induce fever, and are not neutralized by antitoxin.

Answer 35

Endotoxins

Question 36

_______ are Ag that cause a very strong immune response, cause proliferation of T cells, that release cytokines, which induce fever, nausea, vomiting, and shock.

Answer 36

Type 1 (Superantigen)
(Only exotoxin to induce a fever)

Question 37

_______ cause lysis of host cells by disrupting their C.M., by forming channels in the phospholipid layer.

Answer 37

Type 2 (Membrane-Disrupting Toxins)

Question 38

______ consists of 2 parts, is the most common type of exotoxin, and works by inhibiting protein synthesis in host cells.

Answer 38

Type 3 (A-B Toxins)

Question 39

_________ can contaminate the food supply, provoke an allergic response, and are carcinogenic. Aflatoxin is an example of ________.

Answer 39

Fungal Toxins

Question 39

________ causes damage to intestinal lining resulting in diarrhea or dysentery, avoids host defenses by growing in phagocytes and antigenic variation.

Answer 39

Parasitic Protozoa

Question 40

________ are not very pathogenic, use the host’s nutrients or tissue without killing the host, and are present in the GI tract in large numbers interfering with host food absorption. This leads to symptoms of fatigue and weight loss.

Answer 40

Parasitic Helminths