One thing to do, is clean the carboy you store your water in, there are
saprophytic bacteria that will still grow although minimized by your
filters, etc.  I would suggest doing a good clorox wash of carboy, and do
it routinely before refilling.  This problem was discussed on histonet some
time ago, check archives, and there are publications written on the subject.  

At 08:43 AM 1/8/01 +0000, you wrote:
>Hi All,
>
>We had some problems with a Warthin Starry last week. (Is this an
appropriate stain for suspected Cat Scratch disease?) Finished slides were
covered witha background of bacteria. Usual places for these to get in are
either via a dirty section floating ba
>
>So, we set out to make up fresh solutions, change baths etc. Which lead to
any interesting debate. I had always 'assumed' that water from our
deionisation plant would be bug free. Water passes through a coarse filter
on the supply side, passes a UV lamp,
>
>Other suggestion was that we obtain 'sterile' water from Micro. This has
been through process above, then autoclaved. Any bugs would still be there,
but dead. They'd still stain up, though ?
>
>Is there a quick test I can do to see if bugs are present in the holding
tank ? Suggestions range from sending sample to Micro to see if they can
grow anything, or evaporating some water onto a slide, then doing a Gram on
the deposit.
>
>
>Any thoughts please,
>
>Richard
>
>
>
>
Gayle Callis
Veterinary Molecular Biology
Montana State University
Bozeman MT 59717-3610
406 994-4705
406 994-4303