Petri dishes are used, not for eating, but for growing microorganisms. Let’s say you swab someone’s throat to see what’s growing back there. First, you’d dunk the swab into some liquid nutrient broth and incubate it for a few days. This allows the bacteria to grow to petri dish appropriate levels. Next, you’d dip a little loop into the broth and smear some of the liquid onto agar in a petri dish. Depending on the type of agar you have, you can select for certain types of bacteria. From there, depending on how good your swabbing technique was, you’ll be able to separate out the bacteria cells so that after another few days of incubation, you’ll get individual colonies. After that, it’s just a matter of identifying what kind of bacteria made a particular colony!
Alexander Fleming and Mold
There once was a guy named Alexander Fleming who was studying influenza. He swabbed some of his own mucus onto a petri dish while sick with a cold and then left for a two-week vacation. Upon return, perhaps due to an unattentive lab technician, his petri dishes had grown moldy. A fastidious person probably would have thrown them out without a second thought, but not Fleming. He observed them.
This observation would change the course of medicine forever. Fleming noticed that the bacteria didn’t grow near the mold and postulated the mold must be producing something, some kind of chemical, that inhibited bacteria growth. What Fleming had discovered was antibiotics speficially penicillin. Fast forward to today and not only do we use antibiotics liberally, but we overuse it to the point where bacteria are becoming resistant to them!
The War Between Microorganisms
What it really comes down to, this story about the petri dish and penicillin, is that war constantly rages between microorganisms. Right under our nose. Or in our nose. Fungi produce chemicals to inhibit bacteria. Bacteria evolve ways to evade these chemicals. The fungi then must come up with different chemicals. The bacteria continue to evolve. And so on and so forth, the microscopic battle of survival rages on. Thanks to the petri dish and a guy who took a couple weeks off, we’ve been able to harness some of the weapons of this war to keep our own species alive.
No Dishwasher, No Problem
The petri dish is yet another simple and basic science tool that has become so much more. It’s a symbol of life changing and history changing discoveries. It represents how far we’ve come when it comes to medicine and medical technology. What’s even more impressive is that the petri dish is still being used today in labs everywhere.
If you want to own your very own petri dish without having to deal with the whole germs and swabbing thing, then head to our atelier to purchase a petri dish bracelet, necklace, or pair of earrings. Sure, they’re a great gift to yourself, but they also make a great gift for microbiologists, lab technicians, infectious disease doctors, and starry-eyed pre-med students who just finished their microbiology lab class.
written by Science with Evie