Re: Contamination

From: Arnold Pizzey (a.pizzey@UCL.ac.uk)
Date: Wed Aug 29 2001 - 05:01:15 EST


Hello Carlos,

I believe that the following should result in a low contamination rate:

i)Always use water as sheath fluid when not sorting; no point in giving
bacteria a toe hold.

ii)Have some disinfectant in the rinse tank; I use 'Roccal' final conc. 1%+
1% NaNO2.

iii)Forget about using 70% ethanol as a disinfectant; the alcohols are
bactericidal primarily due to dehydration effects; all those environmental
organisms will be predominantly Gram-Positive spore bearing and will either
be resistant to or indeed, welcome alcohol as a handy Carbon source. -Use a
disinfectant instead e.g. 'Virkon' If you positively-absolutely have to
clean the fluidics system then I would suggest a surface active agent such
as  'Decon 90'- you can put this in the sheath tank and flush it through
the system overnight (be sure to remove the inline sheath filter prior to
this. Afterward, you will have to flush the system *many* times to remove
the detergent residue -I only do this once every year or so.

With the above regime, my contamination rate is v.low (I would guess much
less than 10%)

Best regards


Arnold
>
>Hello everybody,
>
>I´d having some problems with a subject:
>
>I¹m a user of a FACScalibur device in my Institute, but at the time to try
>to sorting my neuron cells in this machine, all of the cells go out with a
>lot of debris and contamination from other users, just like: yeas,
>bacteria, protozoan, etc. (I do not know exactly what it is).
>Until this moment I still have not found the way to ensure that my cells
>are free from that contamination. To clean the internal hoses I had been
>testing with a 1:10 chlorine solution let it overnight inside the hoses.
>After that I used DD water (about 1 liter in running mode). And then, just
>then, put on in my PBS solution to start my flow. But when I put the
>purified neurons in culture again, invariably become contaminated.
>Could anybody suggest me some kind of protocol to clean out the Cytometer
>before I begin to sort??... Specially because I need a lonely neurons whom
>are very delicate to survive in a culture medium.
>
>Thank you very much.
>
>Carlos Monter
>IBT-UNAM
>Mexico
>cpmonter@ibt.unam.mx
>
>
>
>

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	Arnold Richard Pizzey
	Department of Haematology
	Royal Free and University College London Medical School
	98 Chenies Mews
	London WC1E 6HX
	U.K

	voice:	+44 020-7679-6234
	Fax:	+44 020-7679-6222
	email:	a.pizzey@ucl.ac.uk
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