unknown 23a rewrite

8/2/2019 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

unknown 23a rewrite

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