Bacterial Pathogenicity

Question 1

What are the 6 factors which promote bacterial colonization inside a host?

Answer 1

1. The ability to adhere to host cells and resist physical removal.
2. The ability to invade host cells.
3. The ability to contact host cells.
4. The ability to resist phagocytic engulfment (attachment and ingestion).
5. The ability to evade immune defenses.
6. The ability to compete for iron and other nutrients.

Question 2

Provide 3 examples of physical, nonspecific removal of bacteria from the human body.

Answer 2

1. Constant shedding of surface epithelial cells
2. Bacterial ejection by coughing, sneezing, vomiting and diarrhea
3. Bacterial removal by bodily fluids (ie saliva, blood, mucous and urine)

Question 3

Name 2 bacterial mechanisms for adherence to host cells.

Answer 3

Pili and adhesins

Question 4

To cause a disease, what 4 things must an organism do?

Answer 4

1. Maintain a reservoir before and after infection in environment or host
2. Enter a new host
3. Replicate and colonise within new host
4. Cause harm to host

Question 5

Whether infectious disease upon exposure occurs depends upon which 3 aspects?

Answer 5

1. The microorganism (ie virulence)
2. The number of bacteria entering the host
3. The quality of the host’s defense mechanisms