Microbiology
Class Three
Spring and Fall Semester
Culture Characteristics
Day 3
•Review culture:
Exp 2B, Isolation of
pure cultures form
SPD, Streak Plate
Dilution, Technique.
(Exp 1, 2A)
Procedure: page 15 &
page 19
•update Journals
Exp 3, Culture
Characteristics
•Discussion
•Procedure: page 23
Charts
Quiz next Week
Case Study
Class schedule( Part One)
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Check results from class 3.
Record results in templates.
Organisms studied – class 3
S. marcescens
B. subtilis
M. luteus
Culture characteristics
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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
Culture observations on the agar
plate
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Color production( chromogenesis). An
example of this is the pink color of
Serratia
Growth pattern and characteristics
Amount of growth( scant or heavy)
Comparison of E. coli and Micrococcus
luteus
Colony morphology
Margin of the colonies
Elevation
Colony morphology
Broth culture( refer to supplement)
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Cloudy
Turbid( Flocculent)
Sediment formation
Pellicle formation
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
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Part One – Completion of class 3
work
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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
Ex# -2/B -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
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Exp 2B,
Isolation of pure
cultures form SPD, Streak
Plate Dilution, Technique.
Exp 3, Culture
Characteristics
Day 4
•Discussion
Procedure: page 15 & page 19 •Procedure: page 23
Culture per table:
Pick, using aseptic
PA, EC,EA , PV,
technique and a needle, a
SA, SS, BS, SE,
unique colony and transfer
to a labeled slant.
Inoculate each
•TSA plate, SPD
ML > yellow
culture into a
•TSA slant, surface labeled media
BS > white
•TSA Broth
Per table
SM > red
Prep for Incubation @ Room Temp
Prep for Incubation @ 37C
Exp 2A, Isolation of Pure Cultures
•Streak Plate Dilution
Technique , SPD
review
•Spread Plate Technique
SM, Serratia marcescens,red
ML, Micrococcus luteus,yellow
cultures
SM/ ML
BS, Bacillus subtilis, white
BS/SM
SM/ ML
BS/SM
22C/24hr
SPD
SPD,SM/ML RF
cultures
SPD,BS/SM RF
SM/ML RF
SP
BS/SM RF
Materials: mixed cultures: SM/ML & BS/SM , one per table, 4 TSA Plates per person
New work( supply table)
Experiment #3
Eight Organisms for Study/Table
 8 Plates
 8 Deeps( if available)
 8 Slants
 8 Broths
Key Organisms for study
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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
Preparation
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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
Review for Quiz One
1.
2.
3.
4.
5.
Aseptic techniques
Culture transfer techniques
Media
Safety precautions
Microscope identification