Human Microflora

Question 1

Skin is difficult to colonize. Why?

Answer 1

It is dry, salty, acidic, and has protective oils

Question 2

Skin microflora
10^__ microbes in moist areas. List 5

Answer 2

10^11
Scalp, ears, armpits, genital, and anal

Question 3

Skin microflora is usually mostly gram _____. Most tolerate ______ and ______. Name 2 species and one disease with causes.

Answer 3

Gram-positive
Tolerate salt and dryness
Staphylococcus epidermidis
Cutiacterium acnes (degrades skin oil, inflames sebaceous glands, and causes acne)

Question 4

Very few microbes survive in the stomach. Why? Name one and the disease it causes, and the other that survives in what atypical condition, with the disease it causes.

Answer 4

High acidity
- Helicobacter plyori (spirochete shape)
[burrow into protective mucous lining and cause ulcers]
- Achlorhydria is loss of acidity caused by malnourishment that allows pathogen growth
- Vibrio cholerae survive, causes cholera

Question 5

The intestine contains between 10^– and 10^– bacteria/gm of feces. The ratio of anaerobes to facultative organisms is __:__

Answer 5

10^11- 10^13 bac/g
1000 anaerobes: 1 facultative

Question 6

Name two organisms that inhabit the intestine and their functions

Answer 6

1) Bacteroides thetaiotaomicron
- anaerobe
- breaks down complex carbs into absorbable compounds
2) Escherichia coli
- facultative anaerobe
- catabolizes gluconate (component of secreted mucus)