Presentation by Andreas Schleicher Tackling the School Absenteeism Crisis 30 ...
Differentiation of Gram (+) cocciMann
1. Differentiation of
Gram (+) cocci
*
Mannitol Salt Agar
*
Gram Stains
*
Mannitol Salt agarSelective mediaSelects for members of the
Staphylococci7.5% NaCl
Differential MediaCarbohydrate source of mannitolPhenol red
3. *
Catalase
(-)
+
*
Hemolysins
*
HemolysinsChecked after growth on sheep red blood cell agar3
kinds of hemolysis:
a-greenish/brownish zone around colonies; not true hemolysis
but discoloration of rbcs
b-zone of rbc hemolysis or clearing; due to the production of
streptolysin O or streptolysin S from Streptococcus sp. or
hemolysins from Staphylococcus aureus
g- no hemolysis
6. • The purpose of this activity is for you to learn how to identify
an
unknown organism in the laboratory.
• You will be given information about your organism.
• Your job is to interpret the data and determine the genus. You
should
attempt to also identify the species. Getting the species wrong
will not
count against you unless you misidentify a species that we have
covered in the laboratory section of the course.
Background Information
• The assignment for this laboratory is a PDF. You MUST print
out the
assignment pages and fill them in by hand, as you would do in
the
laboratory.
• You have been given a tube of bacteria labeled with the letter
M2.
• You streak a loopful of the culture onto Tryptic Soy Agar, and
incubate
at 37C.
Colony morphology
After your
7. incubation, you
pull out your TSA
plate and this is
what you find.
Gram stain morphology
You Gram stain
your organism and
this is what you
observe under the
microscope.
Capsule stain
You perform a
capsule stain.
Glucose Fermentation
You perform a
8. carbohydrate
fermentation test
with glucose.
Lactose Fermentation
You perform a
carbohydrate
fermentation test
with lactose.
Sucrose Fermentation
You perform a
carbohydrate
fermentation test
with sucrose.
Mannitol Fermentation
You perform a
10. organism is
streaked in the
letter C area.
Coagulase
You perform a
coagulase test.
Your organism is
streaked in tube B.
A
B
EMB agar
You streak your
organism on EMB
agar and incubate
at 37C.
11. Motility test
You perform a
motility test. Your
organism is in tube
B.
A B
Hemolysis
You streak your
organism on blood
agar. Your
organism results
are in area A.
TSI
You inoculate your
organism into TSI
agar.
12. Oxidase test
You perform an
oxidase test.
Catalase test
You perform a
catalase test. Your
slide is on the A
half of the slide.
A B
Gelatinase test
You perform a
gelatinase test.
Your organism
is in tube B.
A
13. B
Lipase test
You perform a
lipase test. Your
organism is on the
A half of the plate.
A B
HE
You inoculate your
organism into HE
agar.
Getting Ready for your
Laboratory Unknown
Assignment
14. Colony morphology
• 1) Look at one individual
colony that is separated from
the others.
• 2) Write down each category
and then how each colony
looks.
• For example: the colony
morphology of the organism
highlighted by the arrow is:
Form – entire, Elevation – and so
on through the categories. For the
unknown, you are only required to
complete, Form, Elevation,
Margin, Surface, Opacity and
Chromogenesis
Gram stain morphology
• Gram stain morphology is composed of 3 parts:
1) Is the stained organism gram- positive or gram-negative?
2) What is the morphology (shape) of the individual organisms?
You can have:
Gram (+) rods(bacilli)
15. Gram (-) rods (bacilli)
Gram (+) cocci
Gram (-) cocci
3) Are the cells in a specific arrangement?
Test Results
• Everyone will be given their own
powerpoint that corresponds to the
organism that they are assigned.
The unknown worksheet is a PDF on
D2L. All unknown results MUST be
filled out by hand with a pen, as
they would be in the laboratory.
• 1) As you look at the PowerPoint slide
for each test, there will be a picture of
what happened with your organism.
On the worksheet, fill out what the
results of the test are. For example:
fill out whether this organism on the
right is amylase positive or negative,
not visual observations about the
organism or media.
Summary of Test Results
• In the last section, you will analyze your results and write a
summary.
16. Tell me in your own words, how you used your results to come
to a
presumptive identification.
• Also, draw a flow-chart/ dichotomous key of how you arrived
at your
results. I have provided a link for use as a resource”
• https://creately.com/blog/diagrams/what-is-a-dichotomous-
key/
https://creately.com/blog/diagrams/what-is-a-dichotomous-key/
Identification
• In the spaces provided, write down the identity of your
bacterial
unknown.
• You are being graded on identifying the proper genus. You
will not be
penalized for an incorrect species unless you misidentify a
species that
we covered in the laboratory.
• Know that you are awarded points for each step of the
assignment that
was done correctly. The final identification is only worth a few
extra
points.
1
17. BIOL 362 Unknown Project
Name______________________________________________
Tube ID_______________
Describe the colony morphology of your isolated and pure
bacterium. (Include all 6 categories except for size
and consistency) (12 points)
_____________________________________________________
_____________________________________
_____________________________________________________
_____________________________________
_____________________________________________________
_____________________________________
_____________________________________________________
_____________________________________
_____________________________________________________
_____________________________________
_____________________________________________________
_____________________________________
Gram stain morphology (6 points)
_____________________________________________________
________
Does the organism sporulate? (2 points)
18. _____________________
Record the results of the following tests (36 points):
Capsule
Stain________________________________________________
______________________________
Glucose Fermentation
_____________________________________________________
__________________
Lactose
Fermentation__________________________________________
______________________________
Sucrose
Fermentation__________________________________________
______________________________
Mannitol
Fermentation__________________________________________
_____________________________
Urease________________________________ _______________
_____________________________________
Citrate_______________________________________________
22. What is the genus of your organism? (4 points)
____________________________________
What is the species of your organism?
___________________________________
