Growth & Culture of Bacteria

1
Growth Culture of Bacteria
2
Binary Division

• 1 to 2 to 4 to 8 to ?

3
Phases of Growth

• Lag
• Adapt to nutrients
• Log
• Active growth
• Stationary
• Death Growth rate
• Death
• Nutrients consumed
• pH too low (why?)
• Optimize curves in production

4
(No Transcript)
5
(No Transcript)
6
(No Transcript)
7
Measuring Growth

• Direct Counts
• Petroff-Hauser Chamber
• Pros vs. Cons
• Serial Dilution
• 10-fold serial dilutions
• Pros vs. Cons
• MPN (Most Probable Number)
• Put 10, 1, and 0.1 ml into 10-mls broth
• Repeat 5 times per volume
• Statistical accurate sampling
• Public Health Standards are written for MPN

8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
Measuring Growth-contd

• Turbidity
• Spectrophotometer
• Scale
• Transmittance
• Optical Density or Absorbance
• Filtration
• 0.45 - 0.2 um sizes
• Grid Pattern on Filter
• Standards for Public Health
• 0 E.coli / 100 ml of water
• Also used for sterilization

13
(No Transcript)
14
(No Transcript)
15
Physical Factors -philes

• pH
• Acido-, Neutro-, Alkaliphiles
• Canned foods-Hot Pack vs. Pressure Cooking
• High Acids- tomatoes
• Neutro-corn, beans, meat
• Temperature
• Psychro-, Meso- Thermophiles
• Growth Curve
• Problems

16
(No Transcript)
17
Note the drop-off as you get closer to the
Optimum!
18
What effect would have a fever have on
Mesophiles??
19
Temperature Problems

• Thermophiles
• Hot tubs-public
• Heat Resistant Enzymes in PCR
• Psychrophiles
• Cold food (growth in transit)
• Listeria grows in hot dogs

20
Salt Concentration

• Halophiles
• Great Salt Lake
• Salt Pork

21
(No Transcript)
22
Physical Factors contd

• Moisture
• Beef Jerky
• Lyophilization (Freeze Dry)
• Oxygen
• Aerboes vs. Anaerobes ------ ----------
• Osmotic Pressure
• Pseudomonas grows in distilled water
• Jelly- Jams (high sugar)
• Salt Pork (high salt)

23
Nutritional Factors

• Carbon Source
• Auto- or Hetero-
• CO2 or Organic compounds
• Nitrogen Source
• NO3- gt NO2 gt NH3 to Amino Acids gt Proteins
• Sulfur
• Phosphorus
• Trace Elements
• Fe, some required
• Host Sideophores bind Fe

24
More -trophs

• Auxotrophs
• Can live on simple compounds
• NO3-, Glucose
• Make all Amino Acids, Vitamins, etc.
• Prototrophs
• Require complex compounds
• Vitamins, Amino Acids
• Fastidious
• Most Pathogens

25
Types of Media

• Complex Medium
• Peptones, Yeast Extract
• Fastidious
• Prototrophs
• Synthetic Medium
• Minimal Media
• Auxotrophs

26
Exoenzymes

• Secreted into environment
• Catabolize food products
• Protease, DNAase, Amylase, Lipase
• Used in identification

27
(No Transcript)
28
Oxygen Requirments

• Classification
• Aerobic
• Anaerobic
• Falcultative Anaerobic
• Microaerophilic
• Outline for Topic
• Media
• Cultivation
• Oxygen Toxicity

29
Flluid Thioglycollate Medium (FTM)

• Peptones, Yeast Extracts, Glucose
• Thioglycollate-binds O2
• Agar-slow diffusion of O2
• Rezaruin- O2 indicator

30
FTM Media
31
Growth Chambers

• Candle Jars
• Microaerophillic
• Gas-Paks
• Anaerobes Faculatative Anaerobes

32
(No Transcript)
33
Why Anerobes vs. Aerobes

• O2 is reactive-toxic (binds e-s)
• Requires 4 e-s to form water
• Intermediates are Free Radicals
• Free Radicals steal e-s
• Oxidization of compounds
• Loss of energy from compounds
• DNA molecule breaks

34
(No Transcript)
35
(No Transcript)