I can appreciate the problems you have encountered in relation the
identification of Bacillus species. The mannitol reaction in my
experience is just too unreliable and over estimated as a taxonomic
marker. Addtionally there are some strains of B licheniformous which
produce almost identical reactions to Bacillus cereus during the
We currently use the nitrate reaction,glucose fermentation and VP
reaction to differentiate Bacilus cereus isolates from related species.
This scheme is recommended in the applicable British standard. Again
however the whole system does not stack up to a 100 % definitive
I know some work on ribosommal RNA grouping has been conducted. I had
the thought you might care to investigate this area and perhapes employ
PCR as a alternate to sensor to that employed in ribo typing
In article <8ngd8m$am5$1 at nnrp1.deja.com>,
riyazandrabi at my-deja.com wrote:
> I am working on DETECTION OF FOOD PATHOGENS BY PCR.My work requires me
> to isolate and identify microorganisms from food.Presently I have got
> some dichotomous keys downloaded from internet and schemes from some
> mannuals for this purpose.I particularly follow the Microbiology
> by Cappiccino and Sherman.I want to know if this mannual is sufficient
> for the purpose.If not please help me in finding a reliable scheme of
> identification.I have faced many problems during identification of
> microorganisms.Presently,I'll mention one.In the above mentioned
> the identification scheme recognises only three species of Bacillus
> viz,B.cereus,B.subtilis and B.megatherium.Further,the scheme shows
> all mannitol negative are B.cereus.I took all the mannitol -ve
> species and ran a PCR reaction using the primers specific for
> B.cereus.Do you know what was the result,only some of them showed
> positive results.So please guide me.Thanks in advance.
>> Riyaz Andrabi
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