Unit 3: Artificial Culture Media

Question 1

advantages of traditional culture

Answer 1

• ability to compare amount of growth of diff org
• isolate pathogens for susceptibility testing
• isolated unexpected pathogens

Question 2

disadvantage of traditional culture

Answer 2

TIME. culture usually 16+ hours. days for fungi and mycobacteria

Question 3

purpose of transport media

Answer 3

preserve org in a state as close as possible to condition that was presented when collected from patient

Question 4

goal of transport media

Answer 4

maintain viability w/o overgrowth by any particular org

Question 5

transport media contains

Answer 5

nutrients, moisture support life not reproduction, agar minimize air exposure, neutralizing agent to prevent toxicity

Question 6

3 purposes of culture media

Answer 6

• growth + isolation of all bacteria present
• determination of pathogens vs contaminants or colonizers
• sufficient growth for testing (ID and susceptibility)

Question 7

5 functions of media

Answer 7

• recover small numbers pf potential pathogens
• cover for variety of pathogens
• inhibit normal flora
• aid in preliminary screening of pathogens
• allow differentiation in mixed cultures

Question 8

properties of agar as media (5)

Answer 8

• dissolve readily, clarity w/minimal colour, resilience for streaking
• withstand 121 C sterilization
• gels at 32-40C melts at 85 C
• can be melted and re-solidified
• antibiotics and other heat-labil substances can be added

Question 9

concentration range of agar to make solid plates

Answer 9

1-2 percent

Question 10

concentration range of agar for motility studies

Answer 10

0.05 - 0.5 percent

Question 11

concentration of agar in broths for anaerobes, microaerophiles

Answer 11

0.075-0.1 %. slight gelling inhibits air currents therefor mimics oxygen diffusion