1. Class Three February 7-9 Culture Characteristics
Microbiology
Class Three
February 7-9
Culture Characteristics

2. Class schedule( Part One)
Check results from week 2.
Record results in templates.
Organisms studied – week 2
S. marcescens
B. subtilis
M. luteus
E. coli

3. Culture characteristics
Use supplement and handout to observe the growth of the four organisms in the slant, deep, broth, and on the plate.
Do the organisms look like one of the examples on your sheet?
Try to record their appearance on your templates

4. Culture observations on the agar plate
Color production( chromogenesis). An example of this is the pink color of Serratia
Growth pattern and characteristics
Amount of growth( scant or heavy)

5. Comparison of E. coli and Micrococcus luteus

6. Colony morphology

7. Colony morphology

8. Margin of the colonies

9. Elevation

10. Broth culture( refer to supplement)
Cloudy
Turbid( Flocculent)
Sediment formation
Pellicle formation

11. Slants Is there growth in the bottom ?
Is there growth on the slant itself
What are the growth characteristics on the slant?
Key words
Aerobic
Anaerobic
Facultative

12. Isolation of Pure culture
Observe your dilution streak of your mixed culture
On the bottom of your Petri dish circle colonies of two organisms
Example
ML/SM mixture – circle yellow and pink cultures
With your inoculating loop lift cells from circled colonies and streak on new plate or inoculate a slant per detailed instructions in class

13. Part One – Completion of week 2 work
When you have finished observing all of your cultures
Place all tubes in rack in hazardous waste
Place all plates in cans in hazardous waste
Wipe down desk top

14. New work( supply table)
Eight Organisms for Study/Table
8 Plates
8 Deeps( if available)
8 Slants
8 Broths

15. Preparation Label all tubes and plates carefully
Assign each member of the group 2 organisms
Transfer the organisms to the culture media using aseptic techniques used in weeks one and two

16. Organisms for study Gram negative organisms
PA - Pseudomonas aeruginosa
PV- Proteus vulgaris
EC- Escherichia coli
EA- Enterobacter aerogenes
Gram Positive Organisms
BS - Bacillus subtilis
SA - Staphylococcus aureus
SE - Staphylococcus epidermidis
SS- Streptococcus salivarius

17. Review for Quiz One Aseptic techniques Culture transfer techniques
Media
Safety precautions
Microscope identification