help identify this enterobacteriaceae

Greg Rose gdrose at
Tue Aug 5 20:57:32 EST 1997

Thanks to all who helped me on this project.  As it turns out,  all of
the members of the class who had this same organism also had a weird
mixture of results.  The organism is:  Citrobacter freundii...  weird
huh?  Citrate negative?  

Particular Thanks to Dr. Cartwright at Hennepin County Medical Center.
Couldn't thank you personally Dr. Cartwright, your e-mail return
address didn't work.  Your help was right on the money!

Thanks again!

"Gregory D. Rose" <gdrose at> wrote:

>I am stuck.  Trying to identify my unknown in medical microbiology
>class.  Have it narrowed to maybe.. thats MAYBE two organisms:  E. coli
>and Proteus Vulgaris.  My results have not been overly convincing
>however.  Here goes.

>Medium sized gray colonies with white center, alpha hemolytic on BAP
>It ferments lactose (purple colonies with green sheen on EMB)
>TSI was acid/acid no gas, no H2S produced
>SIM was + + +  (very positive for H2S here but negative on TSI)
>Urease negative
>Pdase negative
>Citrate negative
>Lysine negative
>Ornithine negative
>IMViC - + - -

>Help...  please.

>respond by e-mail if possible to:  gdrose at
>Thank you

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