Try streaking for individual colonies on a Nutrient agar plate and
leaving the plate at room temperature. The S. marcescens should have a
reddish pigment at this temperature. The Staph will not. To differentiate
S. aureus and S. epidermidis, use a coagulase test. S. aureus is
coagulase positive and S. epidermidis is coagulase negative. Innoculate a
small tube of plasma with your G+ cocci and incubate in a 37C water bath
, checking for coagulation every 30 minutes. Hope this helps.
Dr. Jeffrey N. Lee, Biology Dept. E-mail:lee at sol.essex.edu
Essex County College Phone: (201)-877-3535
Newark, NJ 07102
"And all this science, I don't understand.
It's just my job, five days a week,"
- E. John and B. Taupin -
On Mon, 15 Apr 1996, Terry J. Peek wrote:
> I am trying to differentiate between Serratia marcescens and a gram pos. cocci
> that I suspect is Staph epidermidis or S. aureus. I've placed the culture on
> 10% NaCl agar. I'll check the results later this morning. What is the best way
> to seperate these organisms using the resources of a small college lab? Is my
> first step in the right direction? Any suggestions would be appreciated.
> Thanks. Terry