I have tried twice to get it to work. Both to get it to my DNA (which was a big mess in 
the end) and using indirect with anti-bodies (sometimes ok but most of the time huge 
background and a lot of aggregates). My experience is that the q-dots tend to aggregate 
and stick to the membrane of the nucleus. With bacteria I would think accessibility might 
be a problem. The paraffin does not help either but with thin enough sections I guess it 
would be doable. I would try first one q-dot staining before doing multi-colour FISH. The 
few times I was successful the signals were absolutely great, that was indirect using a 
digoxigenin labeled probe. You can also try a combination of both q-dots (when you get one 
or two to work in you FISH) and conventional dyes.

Good luck,
Mariette

on 08-06-2010 21:01 Carl Boswell said the following:
> Hi all,
> A recent query came up here for which I had no answer.  Someone wants to 
> do multichannel FISH (up to 7 labels) and I immediately thought of 
> quantum dots.  However I don't know how easy it is to get Qdots into a 
> fixed bacterium.  The specimen will be paraffin embedded and sectioned 
> gut of an insect.  Any thoughts?
> 
> Thanks,
> c
> 
> Carl A. Boswell, Ph.D.
> Molecular and Cellular Biology
> University of Arizona
> 520-954-7053
> FAX 520-621-3709