The same enterococci; resistant/sensitiv in two media (trimethoprim)

Eberhard Kniehl 100674.1442 at CompuServe.COM
Sat Apr 13 20:51:34 EST 1996

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. 
Good luck
Eberhard Kniehl MD, Karlsruhe, Germany

Eberhard Kniehl
Karlsruhe - Germany

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