The beginning of this summer has been filled with agar plates!! When studying microbes, it is crucial to be able to cultivate and grow these little creatures in the lab. To do this, we fill small plastic dishes with a jelly solution full of nutrients. Each microbe has their own requirements as far as what nutrients or conditions they grow in, so every pathogen is a bit different!
For my Listeria monocytogenes studies, I utilize two main types of agar plates: sheep's blood or an Oxford antibiotic treated plate.
Blood agar plates are some of the best in my opinion! Most human pathogens can grow on these, so they are not selective, but they are consistent. These are used to determine quantity of infection in specific reproductive tissues in my studies.
The Oxford antibiotic treated plate has a chemical in the antibiotic that prevents *almost* everything except Listeria from growing. This is called a selective plate because it only allows our select microbe to grow!