Unknown 23A Rewrite
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Transcript of Unknown 23A Rewrite
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Unknown #2
May 12, 2001
Identifying unknowns
PURPOSETo effectively prepare bacterial smears, Gram stains each smear, and to be able to tell the
difference between Gram positive and Gram negative bacteria
Materials and methodsReagents needed for Gram stain:
Crystal violet
Grams iodine
95% ethyl alcohol
Safranin
Staining tray
Slide warmerGlass slides
Bibulous paperLens paper
Microscope
Inoculating needleBunsen burner
Liquid methanol for fixation
Striker
GlovesGowns
Goggles
Preparation of Bacterial
A drop of distilled water was placed toward the center of the slide. Heat inoculating needle with Bunsen burner until entire wire is red. With same
hand being used to hold inoculating needle, remove lid from TSA broth
containing a pure culture.
Pass neck of the TSA broth tube through flame. Place this small amount of bacterial inoculum into the drop of water on the slide.
Gently agitate the distilled water and spread the inoculum on the slide by moving
the inoculating needle in a circular motion. Pass neck of TSA broth tube through flame and recap. Pass inoculating needle through flame. Place slide with inoculum and water onto slide warmer and heat until dry. Once dry, quickly dip the slide into a solution of liquid methanol to fix or set
the bacteria on the slide. Place the methanol fixed slide onto the slide warmer to
dry completely.
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Part B: Gram Stain1. Place slide containing a bacteria smear on the staining tray.
2. Cover the entire smear with Crystal Violet and allow this reagent to sit on the smear for
one minute.
3. Gently rinse off Crystal Violet stain with distilled water. Aim the water above the smearso as not to dislodge the bacteria with the stream of water.
4. Dry the outer edges of the slide using a Kimwipe.
5. Cover the entire smear with Grams Iodine and allows this reagent to sit on the smear forone minute.
6. Again, holding the slide at a 45 angle, gently rinse off Grams Iodine with distilled
water.7. Dry the outer edges of the slide using a Kimwipe.
8. While counting to three seconds (one thousand one, one thousand two, one thousand
three), add 95% ethyl alcohol in a drop-wise manner.
9. Immediately after reaching three seconds rinse off the ethyl alcohol with distilled water
and dry the outer edges of the slide.10. Cover the entire smear with Safranin and allow this reagent to sit on the smear for 45
seconds.11. Rinse off the Safranin with distilled water and dry the outer edges of the slide.
12. Place the stained slide into a book of bibulous paper and close the book. Apply firm, but
not excessive, pressure to the book to blot the slide dry.13. Air dry as necessary
ResultsGram stained bacterial smear under 1,000 x magnifications. Cells of this smear were bacillusshaped, arranged in chains, and purple in color. The purple color indicates that it is a Gram
positive bacterium.
CONCLUSION/DISCUSSION I assume that the bacterium that is in tube 23A is a gram positive bacterium. It is bacillus
in shape and has pairs in small clusters and is purple in color.
PURPOSE
Unknown #2
Cell shape Bacillus
Cell arrangement Pairs, small clusters
Cell color Purple
Gram reaction Positive
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This test is to see if the microorganism has the ability to resist penicillin. Penicillin resistance is a
sign of
Materials and methods
Mueller Hinton agar plate Striker Gloves Gowns Goggles Inoculating needle Bunsen burner Liquid methanol Tweezers Penicillin disk
Results
The result is that the bacterium was penicillin resistant. There was no zone of clearance. Thebacteria grew right up to the penicillin on the plate. The bacteria on the lawn look afterincubation looked off white and had an irregular form. It also lobate margins, as well as a convex
elevation
CONCLUSION/DISCUSSION
The penicillin resistant is to determine if the bacteria have an abundance b-lactamase. Thebacteria resisted the antibiotic disk you can see it in the picture of the plate with the penicillin
antibiotic disk on it.
Unknown CONCLUSIONAfter running the tests I can assume that the bacterium contained in the test tube is Bacilluscereus.Bacillus cereus is an endemic, soil-dwelling, Gram-positive, rod-shaped, beta hemolytic
bacterium.Bacillus cereus is an aerobe, and like other members of the genus Bacillus can
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produce protective endospores.
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Unknown
23A
GramStainGram positive
Gram
positive rodPurple
Rod
penicillin
restitance
test
Streptococcus pyogenes
streptococcus salivarius
Staphylococcus aureus
Staphylococcus epidemidis
micrococcus roseus
micrococcus luteus
Bacillus subtilis
Bacillus cereus
bacillus
shaped
Bacillus subtilis
Bacillus cereus
penicillin
resistant
Bacillus cereus
penicillin
susceptible
Bacillus subtilis
coccusshaped
Streptococcus pyogenes
Streptococcus Salivarius
Staphylococcus aureus
Staphylococcus
epidemidis
Micrococcus roseus
micrococcus luteus