Bacterial Metabolism

Question 1

What are two ways of molecular diagnosis of a species?

Answer 1

1. PCR to amplify slow growing and noncultivatable bacteria

2. Restriction Fragment Length Polymorphism to see the source of the bacterium

Question 2

What does the oxidase test indicate?

Answer 2

Oxidase test differentiates between aerobes from faculative anaerobes. Tests for presense of cytochrome oxidase.

Question 3

How can you tell the difference between Shigella/Typhoid and E.Coli?

Answer 3

Presense of Hydrogenase in E.Coli - producing CO2 and H2 from formate.

Question 4

What would typically have a positive nitrate test?

Answer 4

Anaerobic Bacteria

Question 5

What temperature do most pathogens grow at?

Answer 5

10-45C, Mesophilic

Question 6

What media selects growth for gram positive over negative?

Answer 6

Mannitol Salt Media - 7.5% NaCl

Inhibits growth of gram negative.