|I have spent 30 years on bacterial identification. We have only
|experience with 'heterotrophic mesophilic groups'
|Today, I would say there are 3 kinds of approaches:
|1. 16S rRNA sequencing. - The rich man's choice
|2. Phenotyping or chemotyping
| A: 10-40 tests - Routine
| B: 30-200 tests - Reference laboratories.
One phenotypic beased method which falls neatly into this category is
pyrolysis mass spectrometry (PyMS)
The major advantages that PyMS has over other diagnostic methods is that it
is rapid, both for a single sample and in the (automated) throughput of
samples. Typical sample time is less than 2 minutes. It is applicable to all
(culturable) micro-organisms and is sensitive enough to allow the analysis of
a single colony (typically 10^6 cells) from a culture plate.
Pyrolysis is the thermal degradation of complex material in an inert
atmosphere or a vacuum. It causes molecules to cleave at their weakest points
to produce smaller, volatile fragments called pyrolysate. A mass spectrometer
can then be used to separate the components of the pyrolysate on the basis of
their mass-to-charge ratio (m/z) to produce a pyrolysis mass spectrum which
can then be used as a "chemical profile" or fingerprint of the complex
General idea is that you analyse your unknowns with reference strains and then
observe which reference strain looks most like your unknown. For more
information visit the Aberystwyth PyMS home page
|3. Miscellanous methods - When you know what you are looking for.
| Serology (Salmonella), selective medium (Legionella), PCR
| (Mycobacterium), etc.
Dr Roy Goodacre
E-mail: rrg at aber.ac.ukhttp://gepasi.dbs.aber.ac.uk/roy/rgcv.htm
Voice : +44 (0)1970 621947 Fax: +44 (0)1970 622354
Snail : Inst Biol Sci, Univ Wales, Aberystwyth, Dyfed SY23 3DA, WALES