Bacteria to Cell Culture - How many bacteria should I add to cell culture (Jan/16/2011 )

Hi,

I've started to a new research about cytokine expression. I'll add bacteria to osteoblast cell culture to see cytokine expression. But I dont know How many bacteria I should add to how many cell? I read articles they say 50, 100 MOI . What is this MOI? How can I calculate it?

Please help me I have to do the experiment tomorrow.

MOI= multiplicity of infection. I'm not a microbiologist, so I don't know how to calculate it, other that it will be a measure of the number of cells needed to cause infection in a particular system or volume.

As bob1 said, MOI is multiplicity of infection. It means the number of infectious units per host/target unit.
So in your case, number of bacteria per osteoblast cell.

Eg. for an MOI of 50 you would have 50 bacteria per single osteoblast.