Different counts in MacConkey Agar

david.lawton1 david.lawton1 at ntlworld.com
Sun May 28 07:54:28 EST 2000


"Lynn" <kees.lyn at xtra.co.nz> wrote in message
news:3930ECAC.728D at xtra.co.nz...
> david.lawton1 wrote:
> >
> > "Yjgent" <yjgent at aol.com> wrote in message
> > news:20000526213618.02915.00000277 at ng-fz1.aol.com...
> > > >In this lab we're working with E.Coli (ATCC 25922 and wild type) and
we
> > > >routinely use MacConkey Agar inclusion plating as a counting method
for
> > > >these microorganisms.
> > >
> > > I was taught a long time ago NOT to measure a colony count from a Mac
> > plate.
> > > Only a non selective agar like TSA or a Blood Agar plate can be used
to
> > count
> > > colonies.
> > > John Gentile M(ASCP)                   President - Rhode Island Apple
> > Group
> > > yjgent at aol.com
> > > Microbiologists do it with culture.
> > Depends on the formulation and what you are trying to count.
> > For years we used a MacConkey that surpressed gram - positives combined
with
> > a blood agar for urine.
> > You can use Mac for water counts, though not recommended
> >
> > Dave
>
>
> Why is it not recommended for water counts, what would be more suitable?
> Lynn

Membrane lauryl sulphate broth, presuming your looking for E. coli or
coliforms
Dave







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