[Microbiology] Re: Brown E.coli

Francesca marco_fra at liceposta.it
Tue Jun 14 07:08:06 EST 2005

Brown colour could be due to the oxidation of some intermediates
of p-toluic acid metabolism. I guess that also the agar plate has
change colour to brown.

"Trond Erik Vee Aune"
<trondaun at biotech.REMOVETHISBEFOREREPLYING.ntnu.no> ha scritto
nel messaggio
news:4290506A.7040001 at biotech.REMOVETHISBEFOREREPLYING.ntnu.no...
> JEDilworth wrote:
> > Years ago (70's) I recall having an E. coli that was
extremely mucoid
> > that produced huge zones on a Kirby Bauer plate (for the
> > drugs). It was from a renal patient and was not typical at
all. Renal
> > patients tend to have very atypical strains of everything
> > they're treated so much.
> >
> > I don't remember if it was brown. I have seen Pseudomonas
> > that was brownish red, however. Was the organism oxidase
positive? I
> > would check that if I had it on a patient's culture plate.
> >
> > I assume you're doing some sort of further testing/research
to elucidate
> > a particular strain of EC. Clinical labs don't go that far,
and I'm
> > sorry if I'm uneducated in that area.
> Thanks for your answer. We're quite sure the strain is lin239,
and that
> there's been no mutations in it. The wierd thing is that when
we grow it
> on solid media with lots of m-toluic acid it produces this
> pigments. I didn't know that E.coli was capable of this, I've
> heard of brown colonies before. So I was wondering if people
have seen
> this happen before, and maybe suggest what the metabolism is. I
> that some other enterococci can produce browin pigments, so it
may be a
> homologue pathway, but which one, and what is the purpose of
the pigments?
> Trond Erik
> > Judy Dilworth, M.T. (ASCP)
> > Microbiology
> >
> > "Trond Erik Vee Aune"
> > <trondaun at biotech.REMOVETHISBEFOREREPLYING.ntnu.no> wrote in
> > news:d6f81c$rei$1 at orkan.itea.ntnu.no...
> >
> >>Hi,
> >>
> >>A collegue of mine have managed to get brown E.coli lin239
colonies on
> >>solid media.
> >
> >
> --
> Trond Erik Vee Aune
> Department of Biotechnology
> Norwegian University of Science and Technology
> Email: trondaun at REMOVETHISBEFOREREPLYING!!biotech.ntnu.no
> http://www.biotech.ntnu.no/molgen
> - Must be sad being a dyslectic, agnostic insomniac, lying
>    awake during the night, wondering if there really is a dog

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