Identifying an Unkown bacteria. - (Aug/27/2008 )
Hi I need help identifying an unknown bacteria.
According to my gram stain I have a gram negative bacteria that are bacillus shaped. However the other test that I have performed suggest that I may have a Gram positive bacteria. The test are as follow:
Catalases Results are negative
Amalyse results are negative
Bacteria does not digest Casine
TSI: Bacterial growth on agar slant the agar was turned yellow/yellow with no bubbles.
SCA: Bacteria did not catablolize citrate
EMB: There was no bacterial growth
MSA: Bacteria turned the media bright yellow.
Pseud Agar F: Clear color colonies on media
VRB: No colony growth on media
MacConky Agar: No colony growth on media.
I need to identify at least the family name. Any help is appreciated.
According to my gram stain I have a gram negative bacteria that are bacillus shaped. However the other test that I have performed suggest that I may have a Gram positive bacteria. The test are as follow:
Catalases Results are negative
Amalyse results are negative
Bacteria does not digest Casine
TSI: Bacterial growth on agar slant the agar was turned yellow/yellow with no bubbles.
SCA: Bacteria did not catablolize citrate
EMB: There was no bacterial growth
MSA: Bacteria turned the media bright yellow.
Pseud Agar F: Clear color colonies on media
VRB: No colony growth on media
MacConky Agar: No colony growth on media.
I need to identify at least the family name. Any help is appreciated.
Gram stain only tells something about cell wall structure, nothing to do with biochemical or physiological processes. If you performed a good Gram stain (good technique is critical for results in everything you do) and you have red rods, then Gram negative it is.
Beware of some bacteria that is not classified using gram, i.e. mycobacterium, because it can be misleading.
Have you tried typing via API 20One?
You could try 16s Ribosomal sequencing and comparing to known species.
at last an answer that makes sense in a molecular biology forum, thank you...
+1
Agree - the results are not consistent with the usual suspect bugs one encounters as unknown in micro teaching labs. You could hope the original question was based on observations of a pure culture. I'd not try API for any grouping. Suggest you start with a fresh streak and a single colony for inoculum. Plan your work in terms of sequence of significant tests and run controls for each. Some of the tests applied above are traditonally signficant for only some bacteria and results with other groups have not been described with accuracy or are variable. For example (and as you may have considered) staph aureus would product acid or acid with no gas on TSI and mycobacteria may or may not grow on EMB. Also run an oxidase.
I'll correct "bacterie" - mycobacteria are certainly Gram positive by properly conducted stain as well as cell wall composition.