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Pseudomonas Aeruginosa in bottled water

drinking water; P.aeruginosa; Pseudomona; drinking water contamination

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carinaevora

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Posted 06 August 2019 - 07:48 AM

Hello.

 

Need your help.

 

I'm doing an investigation work in Angola, in a remote place. I came across this new bottled water company. They have a nice lab but lacks some material. 

I was asked to help them. 

 

The water pH is around 4,76 to 5,20...low EC (4 - 5 microS); no fecal coliforms; E.fecalis; but positive for P.aeruginosa.

 

Detection of P.aeruginosa was carried out using membrane filtration method and incubated in centrimide agar.

 

Then i realise that the CN culture media did not have or was not added the nalidixic acid.

.

The colonies that grow are small, not caracteristic of P.aeruginosa.

 

I do not have any confirmation test (oxidase test), only fluorescente lamps.

 

My question is what can i do? what other bacteria can grow in centrimide agar without nalidixic acid?

 

I attached pictures.

 

Thank you in advance.

 

Carina.Attached File  20190720_151118.jpg   56.99KB   1 downloads


Edited by carinaevora, 06 August 2019 - 07:50 AM.


Charles.C

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Posted 06 August 2019 - 03:20 PM

Hello.

 

Need your help.

 

I'm doing an investigation work in Angola, in a remote place. I came across this new bottled water company. They have a nice lab but lacks some material. 

I was asked to help them. 

 

The water pH is around 4,76 to 5,20...low EC (4 - 5 microS); no fecal coliforms; E.fecalis; but positive for P.aeruginosa.

 

Detection of P.aeruginosa was carried out using membrane filtration method and incubated in centrimide agar.

 

Then i realise that the CN culture media did not have or was not added the nalidixic acid.

.

The colonies that grow are small, not caracteristic of P.aeruginosa.

 

I do not have any confirmation test (oxidase test), only fluorescente lamps.

 

My question is what can i do? what other bacteria can grow in centrimide agar without nalidixic acid?

 

I attached pictures.

 

Thank you in advance.

 

Carina.attachicon.gif 20190720_151118.jpg

 

Hi Carina,

 

Apparently, potentially, various species, eg I saw this quote for water analysis  -
 

 

It was observed a moderate growth of E. coli, E. aerogenes  and  S.  typhimurium  in  the  m-Cetrimide  medium (RGI < 10% in relation to the Triptone soy agar) while S.aureus, P. mirabilis and S. flexneri were inhibited (RGI < 0.001%). (RGI = relative  growth index)

These results confirm that to achieve enough inhibitionin the m-Cetrimide medium, it is necessary to add different inhibitors, including antibiotics, such as  nalidixic acid or fucidin and cephaloridine.

 

 

It is usually more advantageous to focus on confirmation (or not) as to whether the culture obtained matches the target species or not.

You will probably need to obtain some oxidase test strips , etc

 

also see -

 

https://microbiology...ony-morphology/


Kind Regards,

 

Charles.C


carinaevora

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Posted 06 August 2019 - 04:07 PM

Thank you very much.

 

I suspect that but i assumed that might be other Pseudomonas sp…

 

Will focus on confirmation test.

 

Kind regards



Charles.C

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Posted 07 August 2019 - 06:41 AM

Thank you very much.

 

I suspect that but i assumed that might be other Pseudomonas sp…

 

Will focus on confirmation test.

 

Kind regards

 

I sympathise,

 

I have never worked with this species but the confirmation process in BAM looks quite lengthy.

 

Maybe iso's Procedure is simpler (often is).


Kind Regards,

 

Charles.C





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