MIC and zone distributions and ECOFFs

MIC and zone diameter distributions and ECOFFs

  1. EUCAST MIC and zone diameter distributions and ECOFFs
  2. Correlation between MIC values and inhibition zone diameters


The EUCAST software, originally created in 2003, for displaying distributions of MIC-values (generated with methods calibrated to reference broth microdilution or for some agents and species, agar dilution) and inhibition zone diameters (generated with EUCAST standardised disk diffusion methodology) was re-programmed during 2020 and re-launched on 24 November, 2020. Each graph is shown in two versions where one is constructed by just adding up all approved distributions, and the other by giving each distribution equal weight before constructing the aggregated distribution. The later is generated through converting numbers to per cent before aggregation. This prevents large distributions from dominating or even "obliterating" smaller distributions and allows all distributions equal weight. During 2021-2022 distributions are curated in accordance with EUCAST SOP10.2 and all distributions and ECOFF values gradually reviewed. A dedicated software for the calculation of zone diameter ECOFFs has been created and will be applied during 2023.


The distributions are based on collated data from a total of more than 30 000 distributions containing more than several million MIC values and zone diameters. The distributions include data from national and international studies such as resistance surveillance programs and and MIC distributions from published articles, the pharmaceutical industry drug development programmes, veterinary programmes and from individual laboratories. Histograms display wild type and non-wild type organisms, together with EUCAST epidemiological cut-off values (ECOFFs) and tentative ECOFFs (TECOFF).


Access to MIC and zone diameter distribution data.

For researchers interested in using the detailed individual distributions for projects, the database curators may decide to provide that data upon written (email) request. Requests should outline the purpose to which the data will be applied, and based on that information, curators or owners of data may demand to be listed as authors in any publications arising from the research.


The distributions should never be referred to in any epidemiological context since data from many time periods and many countries have been aggregated.


The 2020 updated version of the ECOFFinder program is available from the EUCAST website. This is a tool made available by EUCAST Scientific Secretary John Turnidge for people wanting to assess MIC distribution data. Caveats for use of the program has been added 2020 (see first page of Excel file).


For questions and comments, open the question form EUCAST wild type distributions and choose the relevant subject. 

Contributions of MIC and Zone diameter distributions can be made using the following Excel file templates: 



The curators of the database are currently Gunnar Kahlmeter, Erika Matuschek, Jenny Åhman and John Turnidge.


Submit MIC distributions to Gunnar Kahlmeter or Erika Matuschek.


For Copyright issues, go to the EUCAST home page.






































Instructions and templates for webmaster


1. Instructions 


2. Template for import of MICs and ECOFF stats 


3. Template for import of zones and ECOFF stats 


4. Import of new MIC-data


5. Import of new zone data