Antimicrobial susceptibility testing: harmonisation across Europe

At the turn of this century, there was considerable variation in antimicrobial susceptibility testing (AST) breakpoints used in Europe. The UK, France, The Netherlands, Germany, Norway and Sweden had their own national breakpoint committees and each published their own set of breakpoints. Laboratories in European countries without a national committee often subscribed to the US Clinical and Laboratory Standards Institute (CLSI) breakpoints and AST methodology, as the only system that was perceived as having some international standing.

Such disparity in breakpoints meant that it was difficult for the European clinical community to communicate regarding international AST and surveillance issues. There was a strong possibility that an isolate reported as resistant to a particular antimicrobial in one country could be reported as susceptible in another.

It was clear that harmonisation of AST breakpoints and standardisation of methodology was required across Europe. This would necessitate a joint strategy – the coming together of the six strong national breakpoint committees in Europe, together with representatives from the European Society of Clinical Microbiology and Infectious Diseases (ESCMID), and later with input from the European Medicines Agency (EMEA) and the European Centre for Disease Prevention and Control (ECDC). Thus, the European Committee on Antimicrobial Susceptibility Testing (EUCAST) was formed in 1997.