Bacteria in Boys' and Girls' Living Environments

This topic submitted by Donald, Ashley, Tekk, Eric (frederde@muohio.edu) at 7:03 pm on 10/25/01. Additions were last made on Friday, November 1, 2002. Section: Wagner

Abstract
This lab was designed to enable students to gain a familiarity with the bacteria in their everyday environment, as well as to give them an introduction to procedures used to collect bacteria and grow bacteria to be studied. In this lab, we will ask the students to (1) collect various samples of bacteria, and (2) learn and use proper streak plate techniques so that the data can be easily classified according to how much bacteria is in a sample.

Introduction
To get you more excited about the experiment here are some interesting facts and history of bacteria. Although bacteria live all around of us, most of it is relatively harmless. In fact, only a very small fraction is harmful to us humans (Encarta Online 2001). However, the effect of these few harmful bacteria can be lethal. During the Middle Ages the “Plague” or “Black Death” ravished Europe between 1348-1351 somewhere between 25 and 35 percent of the population died. In certain cities, villages, and areas the number of deaths soared to 60% or higher (Noble et al. 1998). The name of the bacteria that caused this death is Yersinia pestis, and was spread by rats. Another notable outbreak was of Cholera (Vibrio cholaerae) that hit Europe and Asia in the 19th century, and as recently as the 1990s was found in South America. One final bacterial disease is tuberculosis (Mycobacterium tuberculosis), which has claimed millions of human lives throughout human history (Encarta Online 2001). For these reasons, people want to be more aware of the bacteria that they interact with on a daily basis for individual self-knowledge and health. Another common bacteria that live on us that is of health concern is Staphylococcus. This nasty little thing lives in the air and water and on the human body typically on the upper pharynx (throat) and is responsible for pneumonia and septicemia (Encarta Online 2001).
The Dutchman Antoni van Leeuwenhoek recognized bacteria in the late 17th centery. He was a microscope maker and spent many hours grinding and regrinding the glass for his microscopes. He was the first person to describe what he discovered under his lens (Encarta Online 2001). It is due to van Leeuwenhoek that we are able to see bacteria and are thus able to do this experiment. Thanks Antoni!
Since bacteria are so common many people are familiar with them. Have you ever stopped to think about how much of a role bacteria play in your daily lives? Encarta Online Encyclopedia states that bacteria are:
[M]icroorganisms that lack a nucleus and have a cell wall composed of peptidoglycan, a protein-sugar molecule. Bacteria are the most common organisms on earth and are intimately connected to the lives of all organisms.
Bacteria are small and are everywhere. This experiment is designed to show that bacteria live all around us, and are part of our daily lives.
In this experiment the boys’ and girls’ living environments of Peabody Hall (2nd & 3rd floors) will be sampled for bacteria. The bathrooms on each floor and two dorm rooms on each floor will be used for the study. In each of the designated zones (See diagrams for individual specimen zones) samples will be collected and then allowed to grow in Petri dishes. After the maturation process of the bacteria each sample will either be labeled 1- high bacterial growth, 2- medium bacterial growth, 3- low bacterial growth, or 4- no bacterial growth. Based on the amount of bacteria found to have grown in the Petri dish, a point value will be assigned to each. The living environment with the highest bacteria count (based upon total points) will be declared the dirtiest, and will be the recipients of the coveted Dust Bunny Award, which they can then proudly, and rightfully, so display. This is the first, and hopefully annual, competition between the girls’ and boys’ living areas of Peabody Hall for the coveted Dust Bunny Award. On completion of the experiment, each researcher will be able to collect bacteria samples and use proper streak plate techniques.
The purpose for doing this experiment is to discover whose living environment is dirtier, the boys’ or girls’. The Null hypothesis is that neither living environment will have more bacteria than the other. The research hypothesis is that the boys’ living environment (3rd floor) will have more bacteria then the girls’ living environment (2nd floor).
This experiment is designed to enhance the understanding of bacteria and increase the awareness of the quantity of bacteria around us. Because they cannot be seen with the naked eye, we often forget about bacteria and the repercussions they can have on our health. Consequently, sometimes humans are careless and may be exposing themselves to harmful bacteria. We hope this lab will remind us of the importance of cleanliness.

This friendly little guy’s name is Clostridium botulinum and causes botulism poisoning. (http://www.lima.ohio-state.edu/biology/monera.html)
Materials
Cotton swabs
Petri dishes
Agar
Cellophane tape
Masking tape
Pen, pencil, marker
Microscope
Latex gloves

Methods
We based this experiment in part on the Miami University’s MBI 123 class and their labs.

Samples of bacteria will be taken from various locations on the second and third floors of Peabody hall. Locations include the sinks, showers, toilets, and door handles of the bathrooms and keyboards, computer mice, and door handles from dorm rooms (See Diagrams1-3 for more detail). This is done by taking cotton swabs and streaking them in the sampling areas mentioned above. A streak plate technique will be used in order to measure whether there are many bacteria, few bacteria, or no bacteria. In the Petri dish we will streak the cotton swabs seven to ten times on one half (Side A) and two to four times on the other (Side B)(Figs. 1 & 2). The amount of bacteria will be determined by the growth on either half of the dish. If there is no bacterial growth on the entire plate then it will receive a score of 0. If there is low bacterial growth on the heavily stroked half of the plate and none on the lightly stroked half than it will receive a score of 1. If there is high bacterial growth on the heavily stroked side but none on the lightly stroked side it will receive a score of 2. If there is high bacterial growth on the entire plate then it will receive a score of three. A simple spreadsheet will be used to calculate the results. Data will be entered into the spreadsheet and using addition the point values for each floor will be tabulated. The floor that receives the highest score will be deemed the dirtiest and will receive the Dust Bunny Award.

Procedure
1) Go to designated area with your materials (you will receive your location and materials in seminar)
2) Remove a cotton swab from the package. Do not touch either end of the cotton swab.
3) Wipe one end of the cotton swab on the designated surface.
4) Open Petri dish.
5) Wipe the end of the cotton swab about seven to ten times on one half of the agar. Then wipe the same end of the cotton swab on the other half 2-4 times. (See Fig. 1)
6) CLOSE PETRI DISH! Leaving it open can allow bacteria in the air to contaminate the sample.
7) Tape Petri dish closed with cellophane tape.
8) Make sure Petri dish will not open.
9) Really, if it opens the sample will be no good.
10) Record place (location number) and time on a piece of masking tape and apply it on the top of the dish between the two halves. (See Fig. B)
11) Return the Petri dish to the location where you received it.

Fig 1 Fig 2

DIAGRAM 1 -SOUTH BATHROOM

DIAGRAM 2 -NORTH BATHROOM

DIAGRAM 3- LIST OF OBJECTS TO BE SAMPLED FOR BACTERIA
List of Sample Areas
Bathrooms (North & South)
1. Below Seat Back
2. Seat Cover Back
3. Seat Cover Side
4. Toilet Handle (Flusher)
5. Bathroom Door Handle (Inside)
6. Sink Handle Knob (Hot)
7. Sink Drain
8. Paper Towel Dispenser Knob
9. Shower Drain
10. Shower Handle/Knob
Dorm Rooms (2 on each floor)
1. Light Switch
2. Door Handle (Inside)
3. Left Mouse Button
Data Sheet
-Only one data sheet needed

Bacterial Growth High (3pts) Medium (2pts) Low (1pt) None (0pts) Points
Sample
Boys' Floor
(1-13 North Bathroom/Dorm rooms & 14-26 South Bathroom/Dorm rooms)
1
2
3
4
5
6
7
8
9
10
11
12
13
South Bth/Dm
14
15
16
17
18
19
20
21
22
23
24
25
26
TOTAL POINTS

Bacterial Growth High (3pts) Medium (2pts) Low (1pt) None (0pts) Points
Sample
Girls' Floor
(1-13 North Bathroom/Dorm rooms & 14-26 South Bathroom/Dorm rooms)
1
2
3
4
5
6
7
8
9
10
11
12
13
South Bth/Dm
14
15
16
17
18
19
20
21
22
23
24
25
26
TOTAL POINTS

The research timeline is quite simple. On a date to be determined we will take all the samples during class. The samples will be allowed to grow for one week. After the growth process we will then examine the Petri dishes under microscopes to determine the amount of bacterial growth. A T-test will be used to determine if the amount of bacterial growth differs between the boys’ and girls’ living areas.

Day 1 – swab Petri dishes
2 - growth
3 - growth
4- growth
5- growth
6- growth
7- growth
8- Petri dishes will be observed and checked for bacterial growth, then point values will be assigned to each dish.

Works Citied
“Bacteria”. Microsoft Encarta Online Encyclopedia 2001 http://encarta.msn.com (2 Oct.
2001).
Bartlet, Margaret A., (2000) Diagnostic Bacteriology: A study guide. F.A.
Davis Company.
Board, R.G., Jones, Dorothy, & Skinner, F.A., (1992), Identification
Methods in Applied and Environmental Microbiology. Blackwell Scientific
Publications.
Isaac, Susan and Jennings, David, (1995) Microbial Culture: Introduction to
Biotechniques. BIOS Scientific Publishers Limited.
Noble, Thomas F.X., Strauss, Barry S., et al. (1998) Western Civilization: The
Continuing Experiment. Houghton Mifflin Company.
Singleton, Paul, (1992) Introduction to Bacteria: For Students of Biology, Biotechnology,
& Medicine. John Wiley & Sons.
"Staphylococcus," Microsoft Encarta Online Encyclopedia 2001 http://encarta.msn.com (2 Oct. 2001).
Ohio State (Lima) Website: http://www.lima.ohio-state.edu/biology/monera.html (2 Oct. 2001).