Environmental Lab Report

General Microbiology Laboratory

Environmental Report

Steven

10/30/2012

Dr. Angela Case

2012/2013

INTRODUCTION:

We are always interested in what shares our environment that could possibly be harmful us. We have learned that microorganisms are almost everywhere. Including, the water we drink, the air we breathe, and the earth we walk on. This study was done to see the classes of microbes that can be found in some select areas in our environment. We expect to find a variety of potentially harmful organisms in the areas chosen for this study. The question is, what are some of the organisms we may come into contact with daily, that are known, harmful bacteria?

MATERIALS AND METHODS:

The methods that I have learned and observed in class were followed.

Using sterile cotton tipped applicators and sterile saline for dry surfaces, specimens were swabbed, from the following areas.

1. Human Nasal Passage : Labeled as N

2. Human Throat: Labeled as T

3. Public Water Fountain Basin: Labeled as W

4. Seat by Room 208: Labeled as S

5. Bathroom Floor by the Sink: Labeled as B

6. Bottom of a Backpack : Labeled as P

The sample contaminants were then transferred by swab to agar surfaces by the prescribed aseptic transfer technique as follows:

N and T were inoculated on one blood agar dispensed Petri plate side by side, each occupying one half (1/2) of the plate.

W, S, B, and P were placed onto another nutrient agar dispensed Petri plate, each occupying one quarter (1/4) of the plate.

The inoculated plates were then placed into an incubator at 37 degrees centigrade for 24-48 hours (7 days due to class scheduling). After the incubation time the plates were removed from the incubator and the colonies were observed for intensity of growth, number of different colonies, and colony morphology. Results were recorded per Results Table 1.1.

Using the following materials, a sample of two (2) separate colonies from each cultured specimen were transferred to a slide using aseptic techniques. A total of twelve (12) smears were prepared, and heat fixed.

Materials Required:

1. Agar plates containing the cultured specimens

2. Clean glass slides

3. Inoculating loop

4. Bunsen burner

5. Grease pencil

6. Distilled water

7. Paper towel

Procedure:

Step 1. Slides were labeled N1and 2, T1 and 2, W1 and 2, S1 and 2, B1 and 2, P1 and 2 using a wax pencil.

Step 2. A drop of distilled water was placed on each slide just after they were sterilized by a quick pass through the Bunsen burner.

Step 3. Using a sterilized and cooled inoculating loop, a small amount of a sample colony was scraped (holding the top of the dish just slightly open) and gently mixed into the drop of distilled water. This was repeated for all 12 slides.

Step 4. Each slide was passed through the flame until it was dry.

The smears were now heat fixed and ready to be stained. A gram stain technique was performed as follows:

Materials:

Reagents 1. Primary stain - Crystal Violet

2. Mordant - Grams Iodine

3. Decolourizer - Grams Decolourizer

4. Counterstain - Safranin

Procedure:

Step 1. The heat fixed bacterial smears were placed on a slide rack and flooded with the primary stain - Crystal Violet for 30 seconds.

Step 2. Rinsed with distilled water.

Step 3. Mordant - Grams iodine was applied for 10 seconds

Step 4. Rinsed with distilled water.

Step 5. Decolourizer was applied to each slide on a slant at a rate of one drop per second for 10 drops and rinsed immediately.

Step