Unknown Bacteria. Halps!

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: Tue Nov 24, 2009 9:02 pm

Unknown Bacteria. Halps!

Post by weyrcat » Tue Nov 24, 2009 9:33 pm

*Main Interest: My interpretations.. When I think its cleared.. is it? etc,

Incubated at 37*C, on Brain-Heart Agar.
Original Vial has scum at the top, and some sediment at the bottom. Img=http://weyrcat.com/med/09nov_unknown_7004a.png. Also: Blue chip (piece of lid.) Was told to ignore.

Appeared Gram+Cocci(?) under Oil Immersion.
--Well.. mostly.. some appear Bacilli, but there are strings of cocci. Wish I'd snapped the 14-15 unit string. I assumed Rod before I got to Oil Immersion, but it does look so Cocci.

[*]Glucose- Acid, no Gas.
[*]Lactose- No Acid, No Gas.
[*]Sucrose- Acid, no Gas.

[*]Protease+ (Clearing on Milk Plate.)
[*]Lipase- (No Clearing on Tributrin plate)
[*]Amylase? No Growth.

Catalase- Positive. Immediate bubbling. **Note: Lab Tech did this test by putting the H202 on the Tributyrin plate.. wonder if that skewed it.
H2S- (No black gunk.)
Motility... The SIM butt seemed to have no motility (And very little growth. Looked almost like no growth), but the growth slant I did seemed to have a brown haze behind the growth. My apologies for not having these photos.
Indole- negative. No red in sample.
Nitrate- Positive. Ooh, pretty purple.
Citrate- I'll go with Negative, since it looks like nothing grew (and the only things on the list that's positive is S.typhimurium and E.aerogenes anyway.)

Have a generous list to choose from, and though it seemed to point directly at Micrococcus luteus (as a +C stain), someone already had it and it was Given that it needed to be incubated at 30*C. Since mine's Given that it's 37*C, that's right out.

Was told to ReStain, so I'm waiting on the new growth slant (fridged the orig tube).

Going with the Sugars, what it could still possibly be (assuming the initial stain was bad,)

S.marcesens (-R) Differences- Lipase(+) Motility(+)
B.lichenformis (+R) Differences- Lipase(+) Motility(+) *PS Cannot do Spore Stain at this lab.
S.faecalis (+C) Differences- Catalase(-) Protease(-) Motility(-) Nitrate(-) But thats alot.

and close but the Lactose doesn't match:
S.aureus (+C) Differences- Lipase(+) Protease(-)

*Note; one Lab Tech (who isn't supposed to help us) looked confused after she perused my results, mentioning that I got some positives that shouldn't be. Well, there are only 3positive, and SHE convinced me the Protease was PosClearing. She thinks the sample in contaminated. Instructor looked at my Stain, and said its NOT contaminated, but when he looked up my result he had me repeat the number as if "Really? O_o" and recommended I restain... He said if I was still worried about contaminate he'd allow me another Bac without penalty. (If you present your result and are wrong, you have to try again and he drops you a letter grade.) grr
BUT... you only get 3 tries.. couldn't get more than that in before the Dec05 due date anyway! Start my second run tomorrow (after slant is grown.)

I really wanted to figure it out myself. Now.. I'm irritated.

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