oxidase test

[Gary Lum]

Jean MacFaddn's Biochemical tests for identification of medical bacteria
2nd ed says, 

Do not attempt oxidase test from any glucose containing media. 
Fermentation will inhibit oxidase enzyme activity and result in possible
false negatives.  Oxidase should only be performed on non-selective
and/or non-differential media.  Not from EMB, MAC, XLD.

The platinum or plastic or glass is because iron from nichrome can
catalyse oxidation of the phenylenediamine reagent leading to false
positives.

Regards

Gary

PS If I find more stuff at work I'll let you know.  I recommend to my
staff that oxidase should only be performed off blood or chocolate from
our media repertoire.


--
******************************************************** 
Dr Gary Lum
Director of Microbiology and Pathology
Royal Darwin Hospital

Microbiologists do it with culture and sensitivity
Meet me at http://www.ozemail.com.au/~glum/
Come and visit http://www.ozemail.com.au/~agar
E-mail me at mailto:glum at ozemail.com.au
********************************************************