I am working on antibiotic susceptibility testing of Staphylococcus aureus isolated from milk samples. I have used cefixime disc (5μg) in the study but I couldn't find the relevant CLSI standard for it. Staphylococcus aureus?
it depends what you want to show. If you want a generally good comparison standard, you might want to choose a decent drug. Vancomycin for MRSA or cefoxitin (FOX) could be a better standard than the one you mentioned.
Both CLSI, as well as EUCAST, have breakpoints for those on S. aureus