Kitchen Lab
I started out the kitchen lab experiment by buying gelatine, chicken bouillon cubes, small containers and sugar. I added all ingredienys into boiling water, I doubled the recipe because my containers were larger than a petri dish, which was recomended. I stirred the mixture for ten minutes on low heat, so that the mixture cooled some. I then evenly distributed the solution into the two containers, quickly putting the lid on them so that they don't get contaminated.
I left the two containers in the fridge for four hours to let the growth medium set
The first container became my air sample, that I otained by holding the dish right next to the air conditioner
My second container became my door handle sample, I used a Q-tip to swab my outer door handle to my dorm room and rubbed it on the growth medium in a zigzag pattern
Once I obtained the samples I placed them upside down in my closet for several days, about halfway through I discover that the medium is no longer gel like. It had turned into more of a broth, so I flipped the samples over so that I would be able to still have bacterial growth and be able to observe it later.
Air Sample
Door Handle Sample
On day six I retrieved my containers and made my observations, which are detailed below.
Observations
Air Sample
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Bacteria clumped and thicker in middle then had projections out to edge of container, this can best be seen in video above due to the movement
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No shape just general clumped form with smaller projections
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The bacteria was a cloudy white color
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Some air bubbles were present
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Can't observe texture or exact shape because growth medium turned to broth so the bacteria is within the medium rather than on top of it
Door Handle Sample
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Bacteria had several clumps throughout the broth, seemed random in pattern
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No general shape to clumps, however, some were thicker and more concentrated than other
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The bacteria was a cloudy white color, a few green pieces observed as well
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A lot of air bubbles were present on top and within the broth, indicating lots of fermentation
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Again, cannot observe texture or exact shape due to the nature of the broth
Research
With reference to a study (1) done at Drake University on the microbes found on door handles, I can deduce what is normally found on a sampled door knob. The researchers found 49% gram negative bacteria on the culture and they were yellow in color and had a tetrad coccus shape. Gram positive colonies were also found on the door and were a white color and had a staphylococcus aureus arrangement. Staphylococcus aureus, which is a cluster of round cells, is the leading cause of skin and soft tissue infections, they can range from not very important infections to serious infections such as bloodstream infections, pneumonia, or bone and joint infections (2). S. aureus is commonly transmitted to others by hands, which is probably why it was found on a door knob. Most skin infections do not require treatment, however, others require incision and antibiotic treatment. This study gives me one prediction of what could be on a door handle, hoewever, this is a very limited sample.
The most comon bacteria found in the air are Micrococcus, Staphylococcus, Bacillus, and Pseudomonas (3). Micrococcus, which is round in shape, is commonly found on skin and is relatively harmless, however, in immunocompromised people it can be an oppurtunistic pathogen. Staphylococcus is that bacteria discussed previously that can range from very serious to not at all. Bacillus, which is rod shaped, is a tough and harmless bacteria found in soil, water, dust, and sometimes the human digestive tract. The last common bacteria found in air is pseudomonas, a rod shaped bacteria that again is oppurtunistic and won't normally infect healthy individuals. Although the bacteria found in air is probably endless these four give us a good idea of some of them.
Although I wasn't able to determine shape due to my culture medium being more of a broth rather than agar, based on my research I would guess that I would observe some Staphylococcus, which seems like the most common bacteria found in the air and on door handles. If I were to recreate this experiment to try to solve my culture media issues, I would acquire proper petri dishes so that I could follow the recipe more precisely.
(2) http://www.health.state.mn.us/divs/idepc/diseases/staph/basics.html
(3) http://www.moldbacteria.com/bacteria/what-bacteria-are-really-in-indoor-environments.html