Why does my plate have so much/so little bacteria on it?
Not all bacteria can grow in the medium we used, and some grow very well, even in the refrigerator. An empty plate doesn’t mean you don’t have any bacteria, just that the swab didn’t pick up enough or that it picked up bacteria that don’t like this medium. Likewise, plates that look like they’re totally covered in bacteria don’t mean you’re really dirty, just that the bacteria grew a lot on their way back to the lab before we got them onto the plates. Starting from just one cell you can get to millions in just a few hours in the right conditions.
What are the conditions you used to sample and grow the bacteria?
We swabbed skin with sterile q-tips and swirled them in LB media and stored at 4 degrees Celsius. 100 microliters of the liquid media was spread onto LB-agar plates five days after the swab and grown at room temperature. The first set of photos was taken after 48 hours of growth.
Isn’t this kind of gross?
Bacteria have a pretty bad reputation, but we depend on microbes to keep us healthy and only a very small percentage of bacteria can make you sick. We want to understand the bacteria on our skin better, to accept and nurture the bacteria that are part of our bodies’ ecosystems.
Are you collecting my DNA?
Nope, our project focuses exclusively on the bacteria that live on the human skin. In the human body bacterial genes outnumber human genes by a wide margin, we’re interested in learning more about these microbial genomes and how they interact with us and with each other.
What are you going to do with all this bacteria?
We’re not totally sure yet. We’ll probably make some cheese soon, but there are many possibilities as we learn more about the differences and similarities between the microbes we collected from different people, different places, and different body parts.
Have other questions? Send us an email!