Fwd: ID for micro-organims

Yersinia yersinia at CYBERNEX.NET
Tue Dec 7 14:34:46 EST 1999

Dic writes,

<I want know what is the preferred way for identify micro-organisms in 
pharmaceutical laboratory.  Do you use MIDI, VITEK, API or biochemical 
tests (catalase, oxydase,TSI) are suitable?>

My experience is with Vitek and API, in conjunction with some biochemical 
testing. For instance, on all gram pos cocci I'd do a catalase test, and 
on catalase positives, a staphaurex or staphyloslide (then confirmation 
of staphaurex positives with a tube coagulase test). All gram neg rods 
I'd do oxidase tests on, too.

No ID system is perfect, so there are occasions when it is necessary to 
run supplemental tests, usually biochemical or antibiotic (some organisms 
are differentiated by resistance to a particular antibiotic). Two 
examples of this would be Flavobacterium oryzihabitans vs. Chryseomonas 
luteola, which are differentiated by reactions to ONPG and esculin 
hydrolysis, and Staph. hominis vs. Staph. saprophyticus - S. hominis is 
novobiocin susceptible. But by no means are those the only examples.  

I can't speak to the other ID systems, but both Vitek and API come with 
manuals which suggest additional biochemical tests in the event of an 
unclear ID (and API has a very nice telephone database as well).


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