Bacterial Identification Assays

Mark Segal segal.mark at epamail.epa.gov
Tue Jun 17 15:06:07 EST 1997

jjc3 at LEHIGH.EDU wrote:
> I teach a laboratory class in bacteriology for undergraduates. Near the
> end of the class, I have them doing identifications of bacterial unknowns
> using the standard "traditional" methods that we all learned. After they
> were done with their initial identifications last year, I had them use the
> Biolog plate system to do quick re-identifications using modern laboratory
> methods along with computer analysis. My problem is that I was very unhappy
> with the Biolog system; it was unable to clearly identify some bacterial
> strains that the students named easily using the older morpho/physiological
> methods. My question is: does anyone have any recommendations for more
> accurate test systems that I can have my students perform for bacterial
> identification?
> Does any company make anything more accurate then Biolog plates or is that
> the height of technology?
> Thanks for the help,
> Jim Campanella
> Lehigh University
> Dept. of Biological Sciences
> Bethlehem, PA 18015
It appears that the "modern" methods vary greatly in reliability
depending upon whether the isolate is common in clinical situations or
is an isolate rarely associated with humans. The databases upon which
these systems depend seem greatly skewed toward clinical specimens, and
thus should not work as well with environmental non-clinical types.  

If you took your "unknowns" and first checked to see how Biolog matched
with traditional methods, you would know whether the problem is with the
system or the students. Remember that all the systems mentioned by
respondents to your question are still dependent on phenotypic
expression of the traits that they measure, and the problems associated
with variable expression, while the evolving world of bacterial
identification is moving towards genetic, vs phenotypic, comparisons.

Good luck!  I'll be interested in knowing whether any of these systems
is considered reliable for non- clinical isolates.
Mark Segal; U. S. Environmental Protection Agency
401 M St. S.W.; Washington, DC 20460
Ph.:  (202) 260-3389; Email : segal.mark at epamail.epa.gov

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