Professor Kahlmeter has played a pivotal role in international antimicrobial susceptibility testing and clinical breakpoint setting over a period of a quarter of a century, and he served in similar roles both for the Swedish Reference Group for Antibiotics and the British Society of Antimicrobial Chemotherapy. He is known internationally for introducing concepts such as epidemiological cut-off values, devising the EUCAST public consultation process, revising the EUCAST definition of the I-category, introducing the concept of the area of technical uncertainty (ATU), and for developing rapid 4 – 6 hour phenotypic susceptibility testing directly from positive blood culture bottles. 

Starting from 2026, he has stepped down from his duties as technical data co-ordinator in the EUCAST Steering Committee but will continue to contribute to the subcommittee for determining wild type MIC distributions and the setting of epidemiological cut-off values and to be part of the antimycobacterial subcommittee. We thank him wholeheartedly for his efforts for EUCAST for over a quarter of a century.

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The old webmaster bows out and someone new takes over. I have looked after the website and its transitions for exactly 25 years but have no hand in the most recent transition. I am sure you are in good hands and will enjoy the new website.
 

EUCAST assures you that all links to pages and documents that you may have used in national manuals, publications, websites, agency documents and references will continue to be valid also after the transistion. Here is an example - an outdated, previous version of a guidance document on tigecycline dosing , which you may or may not have used for national guidance and have not had reason or time to change. All of these will continue to be active and you should not have to experience "dead links".

I will be available for exchange of views on the old and new websites for some time ahead, as usual at gunnar.kahlmeter(at)eucast.org. The success of EUCAST and the usefulness of the website is evident from the statistics updated a few days ago (see the previous News item). Good luck, enjoy and thank you for your support during all these years. /Gunnar Kahlmeter, EUCAST Technical Data Coordinator and EUCAST Webmaster

Since industry and users sometimes complain that EUCAST fails to warn of upcoming changes we now emphasize that (a) a change is coming, (b) breakpoints will be reduced further and that (c) screening for fluoroquinolone resistance using pefloxacin will be an integral part of proposed changes. We urge laboratories and manufacturers to familiarise themselves with the pefloxacin screen test (already described in the EUCAST breakpoint tables for Enterobacterales, Salmonella enterica and Vibrio spp). Also contact your suppliers of material to ensure that they are ready to meet your requirements.

EUCAST has checked with several major suppliers, and pefloxacin availability is secured for the foreseeable future.

EUCAST has now systematically compared _ MH-F and MH-S to see if the media are interchangeable. MH-F contains 5% mechanically defibrinated horse blood and beta-NAD and will grow also Haemophilus whereas MH-S contains 5% mechanically defibrinated sheep blood but no beta-NAD since MH-S will not grow Haemophilus spp.unless unreasonable amounts of beta-NAD is added.

Based on all results, and excluding Haemophilus, differences between the media were small and EUCAST draws the following conclusions:

• Since MH-F supports growth of more species (in particular, Haemophilus) than MH-S, EUCAST will continue to consider MH-F the standard EUCAST medium for disk diffusion of fastidious organisms unless otherwise specifically stated. This will be evident from the methods section on the website and at the top of species tabs in breakpoint tables. For preparation of MH-F agar plates, see “Preparation of agar plates and broth for EUCAST AST” at https://www.eucast.org/ast_of_bacteria/media_preparation .
• For almost all species and agents (the exception being Haemophilus spp), MH-S can be used instead of MH-F. The MH-S agar plates must contain 5% mechanically defibrinated sheep blood and have the same agar depth as MH-F (4.0 mm with a random variation of ± 0.5 mm). However, EUCAST will not validate MH-S to the same extent as MH-F, and when using MH-S instead of MH-F, it is the responsibility of the user to validate the quality and usability of the medium, for all disks and species included in disk diffusion testing at the laboratory. This is primarily done by use of QC strains but also by comparing local distributions with those available from EUCAST.
• When using MH-S instead of MH-F, all other aspects of the EUCAST disk diffusion method (e.g. inoculum preparation, inoculation of plates, application of disks, disk potencies, incubation and reading of zone diameters) should be adhered to.
• Reading of zone diameters on MH-S should be performed according to EUCAST standard reading instructions for fastidious organisms, except for Streptococcus groups A, B, C and G and trimethoprim-sulfamethoxazole, for which growth within the zone should be ignored and the outer zone edge read.
• EUCAST encourages the involvement of NACs in investigations into the national availability and comparative costs of MH-F and MH-S. NACs can aid by coordinating testing and trouble shooting. NACs may decide to recommend the use of MH-F or MH-S on a national basis. We encourage users to perform further comparisons and validation of MH-S, using the MH agar and disks available locally and to report problems to EUCAST. The EDL can assist in trouble shooting.
• EUCAST will, for each new organism or antimicrobial agent developed for testing on MH-F, perform a parallel, less extensive validation of MH-S to disclose any major discrepancies between the two media.
• Problems with using MH-S, when noted and confirmed by EUCAST, will be listed as a warning on the EUCAST website ( https://www.eucast.org/ast-of-bacteria/warnings ).

Public consultation 1 Aug - 30 Sept, 2025.

EUCAST will start by compiling a list of relevant media manufacturers and distributors each of which will then be asked to respond to a short series of relevant questions. Report company name and contact information to EUCAST via gunnar.kahlmeter[at]eucast.org .

Abstract in CMI.