13 replies to this topic

[prabhubct]

If Colony plated on plate coming below agar, is it contamination?

[Akdor]

Hi,

When you plate bacteria onto a Medium-Agar plate the bacteria should growth on the surface of the agar, otherwise your plate its contaminated from the time of preparation.

[pito]

Depends on what you call "below", its hard to tell.

Sometimes people think its "below", while in fact its just an optical "illusion". Or sometimes bacteria can grow into the medium/agar...

Its hard to tell, but if you have doubts (and never seen this before with that specific bacterium) then just trow it out...

[metionina]

I would say yes, contamination.
But just try to isolate them!

[prabhubct]

pito, on 05 September 2012 - 11:58 AM, said:

Depends on what you call "below", its hard to tell.

Sometimes people think its "below", while in fact its just an optical "illusion". Or sometimes bacteria can grow into the medium/agar...

Its hard to tell, but if you have doubts (and never seen this before with that specific bacterium) then just trow it out...

Its not optical illusion. I collected colony by 1-10ul tip. I have to pierce the gel to reach it. I collected it. It has grown in LB. planning to check it.

Edited by prabhubct, 06 September 2012 - 04:23 AM.

[pito]

prabhubct, on 06 September 2012 - 04:01 AM, said:

pito, on 05 September 2012 - 11:58 AM, said:

Depends on what you call "below", its hard to tell.

Sometimes people think its "below", while in fact its just an optical "illusion". Or sometimes bacteria can grow into the medium/agar...

Its hard to tell, but if you have doubts (and never seen this before with that specific bacterium) then just trow it out...

Its not optical illusion. I collected colony by 1-10ul tip. I have to pierce the gel to reach it. I collected it. It has grown in LB. planning to check it.

Ok

then its most likely contamination.

[Akdor]

The next time you prepare your LB plates take one and keep it Overnight at 37°C. If something grows on it discard the rest. This will save you time and money.

[prabhubct]

pito, on 06 September 2012 - 07:50 AM, said:

prabhubct, on 06 September 2012 - 04:01 AM, said:

pito, on 05 September 2012 - 11:58 AM, said:

Depends on what you call "below", its hard to tell.

Sometimes people think its "below", while in fact its just an optical "illusion". Or sometimes bacteria can grow into the medium/agar...

Its hard to tell, but if you have doubts (and never seen this before with that specific bacterium) then just trow it out...

Its not optical illusion. I collected colony by 1-10ul tip. I have to pierce the gel to reach it. I collected it. It has grown in LB. planning to check it.

Ok

then its most likely contamination.

Can you say what contamination would grow below agar surface? Is it fungi? or bacteria? could they be anaerobic bacteria growing below surface?

[ascacioc]

i would put my money on fungi but you never know unless you spend time to regrow them and do a simple microscopy

[pito]

prabhubct, on 07 September 2012 - 01:03 AM, said:

pito, on 06 September 2012 - 07:50 AM, said:

prabhubct, on 06 September 2012 - 04:01 AM, said:

pito, on 05 September 2012 - 11:58 AM, said:

Depends on what you call "below", its hard to tell.

Sometimes people think its "below", while in fact its just an optical "illusion". Or sometimes bacteria can grow into the medium/agar...

Its hard to tell, but if you have doubts (and never seen this before with that specific bacterium) then just trow it out...

Its not optical illusion. I collected colony by 1-10ul tip. I have to pierce the gel to reach it. I collected it. It has grown in LB. planning to check it.

Ok

then its most likely contamination.

Can you say what contamination would grow below agar surface? Is it fungi? or bacteria? could they be anaerobic bacteria growing below surface?

Most likely fungi yes.

Could be a bacterium too.. hard to tell, you would need to look at it under the microscope.

[prabhubct]

Did fungi not supposed to grow on antibiotic containing LB? b/c they didn't? As far as I know antibiotic may not be inhibiting fungi growth.

[pito]

prabhubct, on 07 September 2012 - 08:09 AM, said:

Did fungi not supposed to grow on antibiotic containing LB? b/c they didn't? As far as I know antibiotic may not be inhibiting fungi growth.

Not sure I understand you correctly.

Fungi can grow on medium containing antibiotic yes.

[prabhubct]

pito, on 07 September 2012 - 08:13 AM, said:

prabhubct, on 07 September 2012 - 08:09 AM, said:

Did fungi not supposed to grow on antibiotic containing LB? b/c they didn't? As far as I know antibiotic may not be inhibiting fungi growth.

Fungi can grow on medium containing antibiotic yes.

but my colony are not growing on medium containing antibiotic. So I am assuming they are not fungi.

Edited by prabhubct, 07 September 2012 - 08:17 AM.

[pito]

prabhubct, on 07 September 2012 - 08:17 AM, said:

pito, on 07 September 2012 - 08:13 AM, said:

prabhubct, on 07 September 2012 - 08:09 AM, said:

Did fungi not supposed to grow on antibiotic containing LB? b/c they didn't? As far as I know antibiotic may not be inhibiting fungi growth.

Fungi can grow on medium containing antibiotic yes.

but my colony are not growing on medium containing antibiotic. So I am assuming they are not fungi.

Oh ok.
Its possible that its not a fungi.
Hard to tell.