Module 4 Bacterial Virulence and Pathogenicity

Question 1

The ability to cause disease by overcoming host defense; all pathogenic bacteria

Answer 1

Pathogenicity

Question 2

The degree of pathogenicity; some pathogen have low virulence

Answer 2

Virulence

Question 3

Factors to cause disease

Answer 3

1. Pathogens must gain access to the host
2. Adherence to host tissues
3. Penetrate or evade host defenses
4. Damage the host tissues ; not all can damage, rather host toxins or waste materials that can cause the disease

Question 4

Portals of Entry

Answer 4

Mucous membranes, skin, parenteral route

Question 5

Increase the virulence of pathogenic species; Prevent the phagocytic cell from adhering to the bacterium (phagocytosis)

Answer 5

Capsules

Question 6

• Heat-resistant and acid-resistant protein produced by Streptococcus pyogenes (virulence factor)
• Prevents phagocytosis
• Helps adhere in epidermal keratinocytes
• Responsible for bacteria to form microcolonies
• Responsible for invasion of epithelial cell

Answer 6

M protein

Question 7

Bacterial enzymes that coagulate (clot) the fibrinogen in blood

Answer 7

Coagulases

Question 8

Is a plasma protein produced by the liver, is converted by coagulases into fibrin, the threads that form a blood clot (shield for phagocytosis)

Answer 8

Fibrinogen

Question 9

• Bacterial enzymes that break down fibrin and thus digest clots formed by the body to isolate the infection.
• Used therapeutically to break down blood clots causing heart attacks
• Opposite of coagulase

Answer 9

Kinases

Question 10

• Another enzyme secreted by certain bacteria, such as Streptococci.
• Involved in the tissue blackening/ gas gangrene of infected wounds
• Help microorganism spread from its initial site of infection
• Produced by some clostridia that cause gas gangrene

Answer 10

Hyaluronidase

Question 11

• Produced by several species of Clostridum
• Facilitates the spread of gas gangrene (myonecrosis)

Answer 11

Collagenase

Question 12

• Enzymes produced by some pathogens that can destroy a class of antibodies called IgA antibodies
• As a defense against adherence of pathogens to mucosal surfaces (nasal and respiratory tract)
• E.g. Nisseria gonorrhea, N. meningitidis

Answer 12

IgA Proteases

Question 13

Surface proteins produced by microbes which when in contact with the host cell membrane, leads to dramatic changes in the membrane at point of contact

Answer 13

Invasins

Question 14

Results to disruption in the cytoskeleton of the host cell

Answer 14

Membrane ruffling

Question 15

Proteins secreted by pathogens to obtain iron. Released into the medium, where they take the iron away from iron-transport proteins by binding the iron even more tightly.

Answer 15

Siderophores

Question 16

Poisonous substances that are produced by certain microorganisms

Answer 16

Toxins

Question 17

The capacity of microorganisms to produce toxins

Answer 17

Toxigenicity

Question 18

Presence of toxins the blood

Answer 18

Toxemia

Question 19

Produced inside some bacteria as a part of their growth and metabolism and are secreted by the bacterium into the surrounding medium or released following lysis.

Answer 19

Exotoxins

Question 20

Are altered exotoxins that cannot cause the disease but can stimulate the body to produce antitoxins

Answer 20

Toxoids

Question 21

Are part of bacterial cells, and not a metabolic product. Part of the outer portion of the cell wall of gram- negative bacterial.

Answer 21

Endotoxins

Question 22

Any life-threatening decrease in blood pressure

Answer 22

Shock

Question 23

Shock caused by bacteria

Answer 23

Septic shock