New EUCAST definitions of S, I and R from 2019 – German physicians are largely not aware of the changes

Purpose On January 1st 2019, the new EUCAST definitions of susceptibility testing categories S, I and R took effect. The changes in the I category have considerable clinical impact because they lead to major changes in the antibiogram, and misinterpretation may result in inappropriate selection and dosing of antibiotics hampering effective treatment of infectious diseases. We assessed if German physicians are aware of the new definitions and their consequences. Methods We conducted a nationwide web-based survey to assess the knowledge on the new definitions of S, I and R. The survey was addressed to clinicians across all medical specialties working in Germany and was open from May 9th to July 30th 2019. Results The answers of 902 participants were included in the analysis. Most participants were employed at hospitals (79.3%) and had already completed specialist training (86.1%). The predominant specialty was internal medicine (50.6%). Of all participants, 45.7% did not know that there was a change in the definitions of S, I and R, and 65.4% did not feel well-informed about the changes. When the participants had to identify true and false statements regarding the new I, substantial knowledge gaps were apparent. Worst results were achieved by those physicians who are not employed in a hospital but work in their own practice. Conclusion Our survey shows that German physicians are insufficiently informed about the new definitions of S, I and R. Further education is strongly needed to ensure optimal treatment of infectious diseases.