RE: Counting bacteria?

From: Olindo Assis Martins Filho (oamfilho@netra.cpqrr.fiocruz.br)
Date: Mon May 17 1999 - 09:13:08 EST


I never use the flow to count since we do not have a way to control the 
flow rate sample to sample without a calibrating beads as true count for 
example. However, if you want to check viability from different culture 
conditions, I suggest you to use trypan blue as a dye and look for changes 
on FL2 axis. Dead cells will be trypan blue positive. I have used a 
protocol that work very well. We prepare a 0,4% trypan blue solution in 
physiologic saline. Use 25 microliters of this solution plus 250 
microliters of cell (bacteria, protozoan, etc) suspension.Incubate for 10 
minutes at room temperature. Run into the cytometer using appropriate 
adjustments for SSCxFSC and the standard for FL1 and FL2 in your 
instrument.



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