Uknown ID: Mixed Results

About microscopic forms of life, including Bacteria, Archea, protozoans, algae and fungi. Topics relating to viruses, viroids and prions also belong here.

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Joined: Thu Apr 30, 2009 2:46 am

Uknown ID: Mixed Results

Post by tmena27 » Thu Apr 30, 2009 2:52 am

Today was the last day of identifying my unknown in lab. Unfortunately, I'm getting some odd results:
For my gram negative bacteria, I have done the following tests and am undecided between E. coli and E. aerogenes
Glucose (+) (with gas bubble)
Lactose (+) (with gas bubble)
Indole (-)
Methyl-red (+)
Voges-Proskauer (+)
Citrate (+)

I'm confused. All my tests are showing Enterobacter aerogenes as my organism. So why is my Methyl-Red test coming out positive (the whole tube is practically red)? Any suggestions? I'm not able to do any more lab tests and must use this information to figure it out. Is there variability with this test?

Would really appreciate some help. Thank you.

King Cobra
King Cobra
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Joined: Thu Feb 14, 2008 7:40 pm

Post by Cat » Sat May 02, 2009 6:12 pm

Your results indicate Citrobacter freundii or Klabsiella ozaenae.

See: ... ;init:.jpg

Why did you do both VP and indole? VP distinguishes between 2 bacteria only: E. coli and Enterobacter. If you have something else it is useless. Indole test already ruled out E. coli.

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