Currently, I would like to confirm the ratio of live/dead pathogen(bacteria) in urine patient sample using dye. However, there are a lot of other cells (including WBC, RBC, Epithelial cell and etc.), thus it is very difficult to figure out the ratio live/dead bacteria. So I think that if I could purify bacteria only from urine patient sample, staining will be working. How can I purify bacteria only from urine patient sample?