Need help identifying Microbiology lab UNKNOWN!

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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Need help identifying Microbiology lab UNKNOWN!

Post by audacity123 » Fri May 01, 2015 6:38 pm

PRS: Positive for fermentation (acid) + gas
PRL: Positive for fermentation (acid) + gas
PRG: Positive for fermentation (acid) + gas
Citrate: Negative (was a green color)
MR: Positive (all red)
VP: Negative (no red color)
Nitrate: Positive w/o adding zinc (nitrate to nitrite)
Thioglycollate Broth: Shows Facultative Anaerobic
SIM: Negative for H2S (no black), Positive for indole and motility
Nutrient Gel: Negative (stayed gelatin in cold water)
Urea: Negative (no color change)
Motility: Positive
Litmus Milk: Negative for Casin (no curd), positive for acid, neg for Litmus Reduction (turned pink)
Catalase: Positive (bubbles)
Oxidase: Negative
TSI: Positive for Glucose, Lactose and/or sucrose fermentation, negative for gas
Pheny: Negative (no color change)
Tryptone Broth: Positive for Indole

Spirit Blue: Negative
EMB: Positive for growth and purple sheen (? might have been green at first since one of my plates grew with a green metallic sheen like E.Coli does but might of changed to purple after a couple weeks of being refridgerated but now I forget unfortunately)
PEA: Negative, no growth
NA: Positive for growth, no color
Mannitol Salt: Negative, no growth.

As for adding Iodine to a starch plate, I stupidly forgot to record the results but I'm pretty sure the entire plate turned black (not sure if thats a positive or negative result)

Gram Stain showed Gram Positive rods, which is why I'm leaning toward some kind of Bacillus, Corynebacterium or Clostridium. Unfortunately, I forgot to look for spores (and have a hard time finding them anyway) and as some charts suggest online, E. Coli matches most of my tests as well (so could it be a possibility that I might have read my gram stain wrong, as stupid as that sounds?) Most charts show conflicting results on most Bacillus and I'm just getting overwhelmed at this point.

Any help or suggestions? I first decided on Bacillus Polymyxa but asked my professor if that was a candidate and she said no (yeah, she didn't give us a list of ALL the possible unknowns - so unfair and frustrating!)

Answers aren't needed, but any kind of help you can provide to help me pick a direction would be extremely appreciated!

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Post by Moseng » Thu Jul 23, 2015 7:37 am

Very comprehensive post here. I really loved it. Thanks

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