Day 0: Starting from the upper left hand corner of each petri dish and going in a clockwise direction I swabbed the surface of my phone, my computer mouse pad on my laptop, under my nail, and the power button on microscope #21. I initially predicted that the power button would have the the largest amount of bacteria and the largest variety of bacteria because there are several different people that use the microscope in our lab. I also had an idea that there would be a fairly large amount of bacteria underneath my nails because of coming in contact with many different surfaces, foods and other types of bacteria filled places or things throughout the day. For my phone screen and laptop I thought there would be bacteria similar to under my nail since I am the main person who used my phone and my laptop.
Day 2: After 2 days I only saw growth from the bacteria under my nail in a lawn formation on both the 24°C and 37°C plates of about 170 individual cells and 2,200 individual bacterial cells, respectively. There appears to be growth on the 24°C plate in the microscope power button section of my plate but I had accidentally touched the swab from under my nail in that spot. The denser lawn on the 37°C plate in comparison to the 24°C plate for under my nail make sense because even though my nails are longer since they are acrylics the bacteria growing underneath them would be used to or thrive at temperatures closer to body temperature - 37°C. At this point I wasn't able to distinguish if there were any different types of bacteria from under my nail. I was surprised that there was not any growth in the other three surfaces that I tested.
Day 7: On the final day of observation I could differentiate between 3 different types of bacteria from under my nail on the 37°C plate. One type was more of an orange color and had 2 colonies, the second type was a white/tan color and surrounded the outer edge of the lawn and the last type was the one I initially saw from day 2 and was a darker yellow color. The 24°C plate for under my nail had 2 distinguishable type of bacteria one that was also a white/tan color and surrounded the outer edge of the lawn and the second type was the one I initially saw from day 2 and was a darker yellow color. My phone screen and computer mouse pad from the laptop still did not show any bacterial growth after one week. However the power button from microscope #21 had 1 type of bacteria forming 3 colonies at 24°C (excluding the growth that came from accidentally touching the "under my nail" swab to that section). Finally on the 37°C plate there was the same type of bacteria as the 24°C plate but with only one colony formed.
Conclusion: Overall I was surprised by my results but also somewhat relieved that the two things I use most often, my phone and my laptop, did not show any growth or I probably would have been pretty grossed out! Under my nails is not much better though, and I did not think there would be THAT much bacteria even though my mom always told me when I was younger to try to wash under my nails too when I washed my hands before eating. I think that since the microscope power button is such a small surface there wasn't bacteria growth and because the bacteria that would be transferred from someone's finger when turning the button on may not be able to survive on that surface and at that temperature in comparison to an environment that it would be accustomed to such as someones hands or fingers. I made several slides of my bacteria from the plates that showed bacterial growth and was not able to obtain any pictures other than what looked like white smears, I was not able to determine the specific types of bacteria on my plates.
Hello Karissa,
ReplyDeleteInteresting how your microscope power button 24°C petri dish had more growth than the 37°C, I expected higher temperature equals more bacteria. But when you think about it, your nails had more bacterial growth at 37°C because body temp is 37°C. Microscopes are kept at room temperature therefore logically, room temperature dish would have more growth because room temperature bacteria are "better" suited for that temp.
Also, the few posts I read, yours was the only with the number of estimated bacterial colonies, that was a good piece of information to add.