Hi you guys, I’ve just got a problem about bacteria shape. At first, I’ve got a broth tube, which has 2 types of bacteria, with Streptococcus in it as a picture below.

 

 

I’m pretty sure they’re Streptococcus. But after I’ve streaked my plate, it seems like they’re Staphylococcus. As it is a cluster shape. (As picture below)

 

In my opinion, I think it is Streptococcus. Maybe it looks like cluster shape because they’re coiled freely.

What do you guys think? Is it possible that Streptococcus can coiled freely that they look like Staphylococcus?

 

Thanks for your answer. I’m very appreciated.

Ps. You don't have to consider gram staining.

Ps2. If you need more photo, just let me know.

Corrected. You're talking about the Gram-negative in both cases. The Gram-positive were bacilli!

 

In my inexperienced opinion they looked like diplococcus, but a pair isn't really enough to reveal all the planes of division, and there are some spots where they look more staphylo-.

How do you know all the Gram-negative cocci were of the same strain? I think I even see some Gram-negative bacilli underneath the Gram-positives on the middle-right.

Edited March 20, 201510 yr by MonDie

Corrected. You're talking about the Gram-negative in both cases. The Gram-positive were bacilli!

 

In my inexperienced opinion they looked like diplococcus, but a pair isn't really enough to reveal all the planes of division, and there are some spots where they look more staphylo-.

How do you know all the Gram-negative cocci were of the same strain? I think I even see some Gram-negative bacilli underneath the Gram-positives on the middle-right.

Yes, you may see gram negative with gram positive in all parts of the slide haha. That's because I have no experience in microbiology. So I'm not sure about my ability to do gram staining. I think they're the same stain because, at first (in broth tube) it has only 2 types of bacteria in there.

 

Yes, at first I thought it was diplococcus. But my friend said that may be it was heterogeneous bacilli bacteria.

Yes, you may see gram negative with gram positive in all parts of the slide haha. That's because I have no experience in microbiology. So I'm not sure about my ability to do gram staining.

 

You did it correctly. Unless they're acid-fast or endospores, either the decolorizer will break down the violet-stained wall and they will stain pink/safranin (-), or they will retain the crystal violet (+).

 

Good luck!

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Gram is a proper noun!

From Wikipedia:

"Staphylococcus aureus is a gram-positive coccal bacterium"

and

"Streptococcus is a genus of coccus (spherical) Gram-positive bacteria belonging to the phylum Firmicutes[3] and the Lactobacillales (lactic acid bacteria) order. Cellular division occurs along a single axis in these bacteria, and thus they grow in chains or pairs, hence the name—from Greek στρεπτός streptos, meaning easily bent or twisted, like a chain (twisted chain)."

 

So some definitely look like Streptococci.