Please note the following susceptibility reporting updates for Staphylococcus spp. that will take effect Monday, June 5, 2023:
- Nafcillin, which is not directly tested, will no longer be reported and will instead be replaced with Oxacillin
- Cefazolin, which is also not directly tested, will be reported (except in CSF) as a “see comment” for 6 months before complete removal on 1/2024
Oxacillin results will trigger the following comments, as appropriate:
- “This organism tested resistant to oxacillin, which infers resistance to nafcillin and cefazolin”
- “This organism tested susceptible to oxacillin, which infers susceptibility to nafcillin and cefazolin”
- Note: In CSF sources, the Oxacillin comment is modified to exclude cefazolin verbiage
Oxacillin breakpoints for the non-S. lugdunensis coagulase-negative Staphylococci will be updated to the current CLSI/FDA breakpoints so as to not overcall methicillin resistance.
- Changed from S ≤0.25/R ≥0.5 to S ≤0.5/R ≥1
Vancomycin will be reported on all staphylococci without cascade/selective reporting rules
Please contact ASET or the Micro Lab with any questions.