EN ISO 20776-1:2006

Foreword
Introduction
1 Scope
2 Terms and definitions
3 Test procedures
  3.1 General
  3.2 Medium
  3.3 Antimicrobial agents
  3.4 Preparation of inoculum
  3.5 Inoculation of microdilution trays
  3.6 Incubation of microdilution trays
  3.7 Reading results
  3.8 Special test situations where the MIC result might give
      unreliable results
4 Quality control
Annex A (normative) Requirements for Mueller-Hinton broth
Bibliography
Annex ZA (informative) Relationship between this European
         Standard and the Essential Requirements of EU
         Directive 98/79

ISO 20776-1:2006 describes one reference method, broth microdilution, for determination of MICs. The MIC reflects the activity of the drug under the described test conditions, and can be interpreted for clinical management purposes by taking into account other factors, such as drug pharmacology or bacterial resistance mechanisms. This allows categorization of bacteria as susceptible (S), intermediate (I), or resistant (R). In addition, MIC distributions can be used to define wild type or non-wild type bacterial populations. Although clinical interpretation of the MIC value is beyond the scope of ISO 20776-1:2006, modifications of the basic method are required for certain antimicrobial agent - bacteria combinations to facilitate clinical interpretation. These modifications are included in a separate table. It is advisable to compare other susceptibility testing methods (e.g. routine methods or diagnostic test devices) with this reference method for validation, in order to ensure comparable and reliable results.