Ch.14: Principles of Disease and Epidemiology

Question 1

_________ ___________: normal microbiota protect the host against colonization by potentially pathogenic microbes by competing for nutrients, producing substances harmful to the invading microbes and affecting conditions such as pH and available oxygen

Answer 1

Competitive exclusion

Question 2

Where in the body are microbes found?

Answer 2

skin, eyes nose, throat, mouth, large intestine, and urinary and reproductive tract

Question 3

Microbes such as E.coli are called __________ ________. They ordinarily do not cause disease in their normal habitat in a healthy person but may do so in a different environment.

Answer 3

opportunistic pathogens

Question 4

Summarization of Koch’s Postulates:

Answer 4

1. The same pathogen must be present in every case of the disease
2. The pathogen must be isolated from the diseased host and grown in pure culture
3. The pathogen from the pure culture must cause the disease when it is inoculated into a healthy susceptible animal
4. The pathogen must be isolated from the inoculated animal and must be shown to be the original organism.