6.2 Bacteria as pathogens

Question 1

How do bacteria cause disease?

Answer 1

Invasion and destruction of host tissues
Production of toxins

Question 2

TRUE/FALSE: Salmonella is an endotoxin

Answer 2

True

Question 3

What type of toxin is Staphylococcus spp. classified as

Answer 3

Exotoxin

Question 4

How do endotoxins affect a host?

Answer 4

• There are lipopolysaccharides in the membranes of gram negative bacteria that have toxic effects
• If the bacterium is broken down they are released
• Often not fatal
• Local to the site of infection

Question 5

Infection and symptoms of salmonella

Answer 5

• Usually in the intestine
• Endotoxins cause inflammation of the gut lining
• Leads to diarrhea as water is not being absorbed
• Taken in through the mouth in contaminated water or food
• Causes fever, weakness, aching

Question 6

How to exotoxins affect a host?

Answer 6

• These are molecules produced by bacteria that are released outside the cell
• Spread around the body in the bloods/body fluids where they affect host cells
• Far from site of infection

Question 7

Infection and symptoms of Staphylococcus Aureus

Answer 7

• Toxins are produced that overstimulate the nonspecific immune system
• Leads to huge inflammatory response (toxic shock) - often fatal
• Only causes disease if it gets inside the tissues of the body through wounds/damage
• Gram positive

Question 8

How does Mycobacterium Tuberculosis act as a pathogen?

Answer 8

Host tissue invasion

Question 9

How does tuberculosis affect the host

Answer 9

Taken into lungs by droplet infection
Invades cells and slowly multiplies, especially in people who are weak, malnourished, or immunocompromised
Thick, waxy covering that protects them from the enzymes of the macrophages allowing them to remain in the lungs dormant