EUCAST disk diffusion test for routine antimicrobial susceptibility testing

During 2009 - 2010 EUCAST is developing a disk diffusion test for routine antimicrobial susceptibility testing. ESCMID has decided to take responsibility for the development and upkeep of the EUCAST disk diffusion test over the next several years.

The method is derived from the Kirby-Bauer method, variants of which are currently widely used in Europe, but is calibrated to EUCAST MIC breakpoints.

The method is based on two media, Mueller-Hinton agar without supplements (MH) for non-fastidious organisms, including enterococci, and MH with 5 % horse blood and 20 mg β-NAD/L (MH-F) for Streptococcus spp. including Streptococcus pneumoniae, Haemophilus spp. and other fastidious organisms. 

The plates are incubated at 35 ± 1 ºC for 18 ± 2 h within 15 minutes from application of the disks. MH plates are incubated in air and MH-F plates in 5% CO2.

Breakpoint tables with tentative zone diameter breakpoints were published December 21, 2009.

EUCAST breakpoints and commercially available material and systems for AST - important information to laboratories (updated 2010-03-16).  CLICK here. 

The preparedness of manufacturers of AST materials (media, plates, disks) and AST systems - click here for the latest information (2010-06-09).