Metabolic products of pathogenic bacteria

N10 naviagtor10 at hotmail.com
Thu Feb 12 18:33:39 EST 2004


"Jane Gonzales" <jrpatto at emory.edu> wrote in message
news:BC51243F.27E6%jrpatto at emory.edu...
> Good Morning!
>
> I'm attempting to provide the research for chemists devising a new method
> for detecting pathogenic bacteria in food, and have what I thought would
be
> a simple question. However, after several days of intensive research, I
have
> not been able to put my finger on it, most likely due to my lack of
working
> knowledge in microbiology!
>
> Would anyone be so kind as to inform me where I can find a list or
database
> (or ANYTHING!!) of the metabolites/products/gases/stuff exuded/given
> off/produced by bacteria,specifically those involved in food poisoning and
> food spoilage? I've located a database of metabolic pathways, but do not
> have the background to determine which of the end-products would actually
be
> excreted by the cell into the environment.
>
> I am grateful for any help that is offered!
>
> ---

Hi Jane

I really dont think you are going to be very lucky on this one unless you
can a find list of
exotic compounds ,characteristic and specific to the types  of organisms you
have mention.

Im fairly familar with the metabolic products of most group II food borne
pathogens and nothing really stikes me as target
which might be usufull as an organism specific identifier  in a food matirx.

Frankly I would be predict that detection or quatation by metabolite
production would be a very
unreliable technique for many reasons.

Firstly consider the example of Salmonella which may be present but capable
of infection in levels as
low as  10 cells per KG of food mateial !!!! You are not going ot detect
many metabolites from that level of contamination
and then ad the various factors of metabolic stress due to food processing
and things become more even difficult for you.

Pcr based systems would and do however detect such low low levels of
contamination with accuracy and rapidity.

Also unless you go for exotics my guess is that most food matrices will
contain a mozaic of microbial metabolites in
almost random patterns depending on the type of processing and various
factors relating to ingredients.

Also may metabolites are common to  several genera and few are group
specific enough in isolation to
unqiuely identify a particular organism or even genus of organism.

Genreal metabolite detection and their effect on conductivity and
capacitance was the basis of  Impdeance technique.

These were higly non specific and required elegant cultural situations to
produce
presumtive isolation of specific target organism..in other words cumbersome
and at best an interesting system for no specific pesudo quatation.


If you turn your attenion to toxin detection  as an idndicator of specific
pathogenic contamination then you pressuppose
toxin is produce in all instanses of contamination which it is not.

I really dont want to pour water on your vison but the best tools we have
for rapid and accurate detection of  food borne pathogens
todate focus  around PCR and ELISA assay. Ememrging techquies invovle probes
tragetign cel wal structures and intra cellualr structures but
not metabolites.

Perhapes you could expand a little more on the proposed technique just in
case I havent fully understood the direction thi sresearch wil take.

Best N10









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