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What bacteria does this TSI test indicate?

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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What bacteria does this TSI test indicate?

Postby SweetSarah » Mon Feb 27, 2012 5:46 am

I'm not sure what organism it would be based on my TSI result. I couldn't find anything like it in the book or online. Any help and further explanation would really be appreciated :)

TSI had red butt (alkaline) and black (H2s) on slant. There was no acid (or yellow) production.
However, I've read online that the H2S can sometimes mask that so I'm not really sure how to tell if there was acid production though I doubt there's any. The majority of the tube is red btw and the black color is only at the top...could that indicate a type of Pseudomonas maybe? thanks

Here's some my other test results that makes me think my Enterobacteriaceae maybe a Pseudomonas (but I could be wrong for all I know it may be something else?? though I doubt it's Proteus anymore due to the glucose test)

Glucose: negative (tube stayed same color, not change at all)
Lactose: Negative
Nitrate: positive
Urease: negative (tube stayed same yellow color)

TSI: Alkaline (red) butt with black slant.
**How do I write this result by the way?? such as in like A/K or K/K form or something along the lines if that makes sense.
Also, it looked like tiny, thin pink rods under the microscope. and all the media plates I used (for example blood agar, MAC, and PEA) all had a black coloration formed on it, so am assuming it's hydrogen sulfide (H2S).
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Postby SweetSarah » Mon Mar 05, 2012 11:02 am

***hey everyone never mind about this question./ I already figured it out just saying this in case anyone else try to answer but I have other questions I could use your help on!
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Re: What bacteria does this TSI test indicate?

Postby eaglepriest » Sun Apr 29, 2012 11:59 am

sounds like proteus. is that what it turned out to be?
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Re: What bacteria does this TSI test indicate?

Postby SweetSarah » Sat Jun 09, 2012 11:30 am

eaglepriest wrote:sounds like proteus. is that what it turned out to be?


Hey, I actually thought that was what it would be...but actually it turned out to be pseudomonas. I'm still a bit shocked with the correct answer, but at least I was able to figure it out by time....but with some help like I've got here and from others... but I'm done with that class now and glad I got to ace it. Sorry about not replying before. I honestly thought no one would answer since I made that note and just actually haven't bothered checking up on my old questions here. Thanks though for being concerned and asking me about it! :)
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Re: What bacteria does this TSI test indicate?

Postby SweetSarah » Sat Jun 09, 2012 11:36 am

eaglepriest wrote:sounds like proteus. is that what it turned out to be?

I also want to add: My gram negative was pseudomonas, which I got right, but unfortunately I got my gram positive wrong (I was thinking along the lines of micrococcus or the side of bacteria that were catalase positive but it turned out it was actually negative and I did that one test wrong somehow (I dont know why or how that could happen!) but it was supposed to be s.pneumonia). Just because of one little mistake, all my results ended up being ruined and not making sense, hence why I kept asking questions here since I was confused outta my mind! :|
So that did knock my grade down but at least I fortunately made it up with the final exam! the unknowns experiments almost killed my grade. I'm still surprised I got an A. but I barely made it by a point! Still happy though, I mean an A is an A, not like they can tell what percentage it was cuz still it's an A :)
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Postby JorgeLobo » Sat Jun 09, 2012 11:44 am

Good job Sarah. It couldn't have been Proteus spp.. Red butt is consistent with Glucose fermentation - characteristic of enterics. Was it Shewanella (formerly Pseudomonas) putrefaciens?
A common problem of most ID excercises is that they don't ask students to run controls - that would have helped with your catalase problem. So you didn;t use blood agar for the Gram +?
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