I recently grew bacteria in a petri dish. What kind is it??

Question

Description: It's now white, circular, flat, and translucent.

If anyone knows the name of this bacteria that would be helpful, or even an online guide to identify it based on pictures.

Answer 1

can you do a gram stain on it? see if it's gram positive or gram negative. it sounds like a staph. to me. if it's gram positive, put a drop of hydrogen peroxide on it (the kind in your medicine cabinet will work, you don't have to have the concentrated stuff). if it bubbles, it's probably staph.

the first step is the gram stain.

if it's gram positive, do a catalase test (that's what the hydrogen peroxide test is). if it's positive, it's staph. if it's negative, it may be strep.

if it's gram negative, and is a short fat rod, it's more than likely a coliform, since they are so abundant. follow up tests on these are oxidase and indole testing, then go from there.

the source of your specimen will give you a clue as to what the possibilities are.

Answer 2

tough question - most of the bacterial colonies I've grown are like that. How did you inoculate the plate with the bacteria? Did you apply some kind of culture to the plate or did you just leave it open to the air, or what? That might possibly give you a clue, but I expect that you're going to need some more details than just the colony (plaque) appearance.

Answer 3

that's hard to say. you'd have to take a sample and look in a microscope to get the specific bacteria.