Introduction
In groups of four, we were required to design our own experiment that involved measuring bacteria. Using the data, we created a formal lab report that explained our findings. We also created a poster that concisely displayed our results.
Peer Review and Instructor Feedback
These five images above show the edits we made to the report
Poster
Final Draft
Bacteria Quantity on Post-Hand Washing Surfaces
Abstract
This study’s aim is to raise awareness about what object that is touched after people wash their hands contains the most bacteria, namely the tissue dispenser and the bathroom doorknob. Bacteria was gathered from the men’s and women’s bathrooms on the ground floor of Shepard Hall. The tissue dispenser and the door plate from the men’s and women’s bathroom were swabbed and then placed on the Luria Broth in a petri dish, where the bacteria was sealed with tape and grown for a week. The results state that the number of bacteria on the tissue dispenser in the men’s bathroom was higher than that on the doorknob; however, the women’s bathroom displayed higher amounts of bacteria on the doorknob than on the tissue dispenser.
Introduction
Bacteria are found everywhere and most strains can cause diseases, which is why it is crucial to be aware of how people interact bacteria. One of the best ways to reduce the risk of transmitting bacteria is by maintaining hand hygiene. Bathrooms are havens for bacteria, and people are concerned if touching objects after washing their hands reduces the risk of contamination.
The purpose of this experiment is to see which bathroom, either men or women, has the most bacteria on objects that are touched post-hand washing. In this experiment, the amount of bacteria on the tissue dispenser and the doorknob of the men and women bathroom is being tested because they are the two most commonly touched areas after people wash their hands. To conduct this experiment, bacteria from the tissue dispenser and the doorknob will be collected using the sterilized swabs and grown in a petri dish for a week.
The basis for this research comes from a study conducted at the University of Westminster, London by Dr. Patrick Kimmit. The study is called, “Evaluation of the potential for virus dispersal during hand drying: a comparison of three methods”. In this study, Dr. Kimmit analyzed the amount of bacteria dispersed by the hand dryers, a post-hand washing object, in public bathrooms. What they concluded was that bacteria and viruses can spread rapidly through hand dryers. What Dr. Kimmit’s team provides is a catalyst for further investigation on how people can reduce bacterial contamination in a bathroom after washing their own hands.
For this experiment, it was hypothesized that in both bathrooms, the amount of bacteria on the tissue dispenser will be greater than the amount of bacteria on the doorknob because the moisture from the hands present on the tissue dispenser will allow for greater bacteria reproduction.
Materials and Methods
To conduct this experiment, both the men’s and women’s ground floor bathrooms in Shepherd Hall to gather bacteria were selected for this study. A total of four agar plate dishes and four cotton swabs were used to collect bacteria from the bathrooms. An agar plate, known as a petri dish, contains a solid growth medium called Luria Broth (LB), which contains agar plus nutrients used for the culture and growth of bacteria.
In the experiment, two agar plate dishes were used for gathering bacteria in the men’s bathroom, while the other two dishes were used for gathering bacteria in the women’s bathroom. In each of the bathrooms, one agar plate dish was used to gather bacteria from the doorknobs, while the other agar plate dish was used to gather bacteria from the tissue dispenser using one separate swab for each collection of bacteria. For the tissue dispensers, the entire front side of the push handle was swabbed thoroughly in both bathrooms. Similarly, the doorknob was completely swabbed, leaving no part untouched.
After gathering bacteria from both the doorknobs and tissue dispensers in the men’s and women’s bathroom, the plates were secured by taping the lid onto the gel base. Additionally, the front of each plate was labeled with the bacteria collector’s name and the location from which the bacteria was collected. They were then placed in plastic bags, separating them by gender.
All the plates were placed in a box that receives no light, and a room that was approximately 78℉. After one week, the agar plate dishes were removed from the box, and the observation period began. Each plate was analyzed for the quantity of dots, length of large pieces, shape, and color of bacteria. Through these observations, the location that carried the most bacteria was determined.
Results
Figure 1. Comparison of bacteria found in bathrooms
| Bathroom | Object | # of yellow colored bacteria | # of white colored bacteria |
| Women | Tissue Dispenser | 1 | 4 |
| Doorknob | 2 | 2 | |
| Men | Tissue Dispenser | 4 | 10 |
| Doorknob | 3 | 1 |
The results partially support the hypothesis, because the men’s bathroom follows the hypothesized trend, while the women’s bathroom does not. For the men’s bathroom, the bacteria grown from the tissue dispenser resembled a long paint splat that was dark yellow. There were also 14 bacterial dots that surrounded the longer bacteria. However, the bacteria from the doorknob had four tiny dots, three that are yellow and one that was white, none of which were near the magnitude of the male tissue dispenser.
The swabs of bacteria from the women’s bathroom revealed that the tissue dispenser had four little white dots and one yellow dot. From the doorknob, the bacteria appeared to consist of one that was lily pad shaped and appeared to be slightly clear. Although the doorknob in the women’s bathroom had fewer bacterial dots, the total amount of bacteria was greater in the doorknob gel plate. Figure 1 displays the differences between the color of the bacteria and the number of bacteria found.
Figure 2. Bacteria collected from tissue dispenser in men’s bathroom
Figure 3. Bacteria collected from doorknob in men’s bathroom
Figure 4. Bacteria collected from tissue dispenser in women’s bathroom
Figure 5. Bacteria collected from doorknob in women’s bathroom
Discussion
The initial hypothesis was proven partially correct after the completion of this experiment. The results that were determined through the study demonstrated that the women’s bathroom had greater amounts of bacteria on the doorknob than the tissue dispenser. However, the men’s bathroom confirmed what was stated in the hypothesis, that there was a greater amount of bacteria on the tissue dispenser than the doorknob.
A reduced amount of bacteria on the tissue dispenser in the women’s bathroom can be justified by the lack of moisture on the dispenser or reduced bacteria contact. Without the moisture, bacteria would find it more difficult to reproduce; without individuals touching the dispenser, bacteria levels would never increase. Similarly, an increased amount of bacteria on the doorknob in the women’s bathroom is likely due to increased moisture, or increased bacteria contact.
This leads to the conclusion that in the women’s bathroom, individuals are either not washing their hands or not drying their hands. If individuals do not wash their hands after using the restroom, they have no need to touch the dispenser, and most of the bacteria on their hands are left on the doorknob. If individuals do not dry their hands, they have no need for a tissue which allows them to avoid the dispenser, and they add moisture to the doorknob, making it bacteria-friendly.
There are several aspects of this experiment that require attention. Before collecting the bacteria, there was no knowledge of how often each object was cleaned. This could have led to inaccurate findings regarding the quantity of bacteria found on each surface if they were disinfected. While the bacteria was growing, the temperature was not monitored for constancy. Fluctuations in temperature can cause abnormal bacterial growth. Also, no precise tools were used to quantify the number of bacteria. Results were based on observation and qualitative estimates that can vary with large percentages of error.
Previous studies, like that of Dr. Kimmit, have noted how bacteria and viruses can disperse rapidly through hand dryers. Since hand cleaning is a concern for individuals, especially in healthcare settings and the food industry, further research can compare the efficacy of tissue dispensers compared to hand dryers.
References
Kimmitt P, Redway K. Evaluation of the potential for virus dispersal during hand drying: a comparison of three methods. Journal of Applied Microbiology. 2016;120(2):478–486. https://onlinelibrary.wiley.com/doi/full/10.1111/jam.13014
Self Assessment
One thing that I was able to achieve during this assignment was my engagement with the collaborative and social aspects of the writing process. Since we worked in groups, this was a prime opportunity to work with others a collectively write an essay. When writing the full report, I noticed the differences between my style of writing and my group members’. These linguistic differences were obstacles because they impeded the sensibility of the writing. Using the writing process, we were able to edit, revise, and clarify the entire piece.
For this assignment, we also had to conduct research. Utilizing online databases, and library resources, we were able to find articles that related to our topic.
In our writing, we had to formulate and articulate a stance, which I think we successfully did. Our assignment clearly stated the difference in bacteria between bathrooms and the results we observed.
Finally, this was a unique opportunity to engage in genre analysis and multimodal composing because we wrote a lab report and created a scientific poster. Both of these are new mediums of science writing that we had not done in class before.
Farhan's Writing for the Sciences Portfolio 