staphylococcus aureus

[news]

I work in a medical microbiology labor
I have a problem with koagulase reaction
Can somebody help me????
we work with a koagulase -reagens from the firma
murex
but in the last time we have more and more false negative
reations.
Can give me some tips or know someone better products?
Especially  with MRSA we have problems and with "normal" resistant
Staphylococci too
thx


Sorry of my bad English ( isn't my mother- language)