Sverre Skeidsvoll wrote:
>My problem is as follows:
>We have used same enterococci to grow against trimethoprim in
>two different media.
>Media nr.1 was from Mueller-hinten and showed enterococci
>sensitiv to trimethoprim !
>Media nr.2 was from Gibco and showed the same enterococci
>resistant to trimethoprim !
>I cannot understand why this same bacteria is sensitiv and then
>resistant in two media
>that should be the same. Different agar ?
>Please help me !
You didnt mention type of testing nor specify medium nr. 2.
A general problem in testing against trim can be that media
contain folic acid, which "couteracts" the effect of blockage of
folic acid synthesis of trim. Mueller-Hinton when free of
trim-antagonists is good for testing trim.
Eberhard Kniehl MD, Karlsruhe, Germany
Karlsruhe - Germany