Micro lab #7

What are the three types of heat methods used to control microorganisms? provide exampmes

Low temperature (Freezing)
Dry heat (Hot air ovens)
Moist heat (Autoclaving)

What are the ways of determining the effectiveness of heat? (3)

TDT (thermal death time)
TDP (thermal death point)
DRT (decimal reduction time)

describe TDT (thermal death time)

Minimum time to kill 100% at a fixed temperature.

Describe TDP

Minimum temperature to kill 100% in 10 minutes.

Describe DRT

Time to reduce the population by 90% (1-log) at a fixed temperature.

What are the 2 types of raditation?

Ionizing (Xrays/gamma)
non Ionizing (UV)

What does Uv do ?

Makes two T's stick together (thymine dimer).

What are the 2 ways that cells can fix the UV describe them

Light repair (Photolyase unsticks the T's.)
dark repair (Cut out damaged DNA and replace it)

____ waveleght radiation has ___ deleterius effect

shorter
more

What are the common antimicrobial agents describe them ?

disinfectants (objects)
Antiseptics (skin)
Antibiotics (inside body)

How can you idenetify the effectivenest of antimicrobial agents ?

dilution test

What is the disk diffusion method (kirby bauer)

shows what antibiotics is best at stopping/killing bacteria by looking at clear areas

describe what this measn on a Kirby Bauer test ?
Big clear circle Susceptible =

Small clear circle Intermediate =

No clear circle Resistant=

The antibiotic works well.

It works a little.

It doesn't work.

the kirby bauer (disk diffusion method ) is a ___

qualitative

Whats an e text ?

help find the smallest amount of an antibiotic needed to stop bacteria from growing.

What is MIC? what does it mean?

Minimum Inhibitory Concentration (It is the smallest amount of antibiotic that stops bacteria from growing.)

What is the Broth Dilution Test?

test that finds the smallest amount of an antibiotic needed to stop bacteria from growing (MIC).

difference between all 3 ?
Kirby-Baue
E-test
Broth dilution

Which antibiotic works?
How much antibiotic is needed?
How much antibiotic is needed?

how do you determine the MIC in broth?

the first clear one