I know that we have Gram + and Gram - bacteria. I just noticed that there is a third category: non-gram staining !!!! What is considered to be non-gram staining???!!!!
Gram - = a bacterium that does not retain the violet stain used in Gram's method.
Gram + = a bacterium that retains the violet stain used in Gram's method
Does it make sense to have a 3rd category?
Here are some examples:
Gram + = Corynebacterium
Gram - = Bordetella
non-gram staining = Ehrlichia (obligate intracellular)

I know that we have Gram + and Gram - bacteria. I just noticed that there is a third category: non-gram staining !!!! What is considered to be non-gram staining???!!!!
Gram - = a bacterium that does not retain the violet stain used in Gram's method.
Gram + = a bacterium that retains the violet stain used in Gram's method
Does it make sense to have a 3rd category?
Here are some examples:
Gram + = Corynebacterium
Gram - = Bordetella
non-gram staining = Ehrlichia (obligate intracellular)

Hi,
Yes, there are some non gram staining bacteria. Mycoplasma and ureaplasma are the example.
Even, mycobacterium species does not stain well on gram stain. But,they are considered gram positive.
Legionella is considered gram negetive, but they are also poorly stained
But, I am not sure about non-gram staining = Ehrlichia (obligate intracellular)

I hope this helps.

Hi,
Yes, there are some non gram staining bacteria. Mycoplasma and ureaplasma are the example....they are also poorly stained

Thanks a bunch.


But, I am not sure about non-gram staining = Ehrlichia (obligate intracellular)


Ehrlichia = Strict intracellular pathogen of white blood cells. They belong to family Rickettsiaceae. They cause Erlichiosis which is a tick-trasmitted zoonosis. My book considers them non-gram staining. (they seem to be related to the ATP deficient Chlamydia but they apparently can make some ATP (not as much as needed).)


I hope this helps.

It helped a lot. Thanks :)

Thanks a bunch.



Ehrlichia = Strict intracellular pathogen of white blood cells. They belong to family Rickettsiaceae. They cause Erlichiosis which is a tick-trasmitted zoonosis. My book considers them non-gram staining. (they seem to be related to the ATP deficient Chlamydia but they apparently can make some ATP (not as much as needed).)



It helped a lot. Thanks :)
Thanks a lot.

What I understood is that most of the spirochtes, chlamydie and rickettsiae are very thin. So they do not stain well on gram stain. But, they are considered gram negetive.
Thanks for mentioning that Ehrlichia belong to family Rickettsiaceae

Thanks a lot.

What I understood is that most of the spirochtes, chlamydie and rickettsiae are very thin. So they do not stain well on gram stain...

Hmmm... I don't think you can say that about Spirochetes. For example, Borrelia, Treponema & Leptospira are definitely gram negative. I doubt they even come close to being poorly or non-gram staining. Rickettsia and Chlamydia most likely don't stain very well. I guess we can make a general statement about those. Legionella & Mycobacteria are aerobic Bacilli but we have many Bacilli that are clearly gram - or gram +. I don't think we can make a general statement about Bacilli.

"Non-Gram staining" mostly are acid fast bacilli.

"Non-Gram staining" mostly are acid fast bacilli.

hmmm...I don't think so. Only Mycobacteria are acid-fast bacilli. All the other ones aren't.

hmmm...I don't think so. Only Mycobacteria are acid-fast bacilli. All the other ones aren't.
Ehrlichiae are gram-negative cocci and stain dark blue to purple with Romanowsky stain(due to their acidophillic nature). Mycoplasma and Nocardia are acid fast. What else? :)

Ehrlichiae are gram-negative cocci and stain dark blue to purple with Romanowsky stain(due to their acidophillic nature). Mycoplasma and Nocardia are acid fast. What else? :)

You said acid-fast bacilli, not cocci (Ehrlichiae are not bacilli). Nocardia are partially acid-fast. Mycobacteria are acid-fast. Mycoplasmas don't have peptidoglycan but I am not so sure if it's acid-fast. I'll have to check on that. If you say they are they probably are.

You said acid-fast bacilli, not cocci (Ehrlichiae are not bacilli). Nocardia are partially acid-fast. Mycobacteria are acid-fast. Mycoplasmas don't have peptidoglycan but I am not so sure if it's acid-fast. I'll have to check on that. If you say they are they probably are.

Oh.. my mistake I meant if they are neither gram positive nor gram negative they most probably will be acid fast bacteria (not bacilli). :)

Hi,
Is this link helping?

http://www.buddycom.com/bacteria/nongram.html