Variability and interpretability of benzylpenicillin inhibition zone edges in Staphylococcus aureus – a multi-center study in Austria

In summary, our study demonstrates that benzylpenicillin susceptibility testing using the EUCAST-recommended methodology is feasible, but accurate and reproducible assessment of zone edges requires both experience and optimal materials. Thorough validation of locally used materials is therefore essential before implementing this approach for routine use.