NA 176

DIN Standards Committee Health Technologies

Project

Clinical laboratory testing and in vitro diagnostic test systems - Susceptibility testing of infectious agents and evaluation of performance of antimicrobial susceptibility test devices - Part 3: Discdiffusion agar reference method for testing the in vitro activity of antimicrobial agents against rapidly growing aerobic bacteria involved in infectious diseases

Abstract

This part of ISO 20776 describes one reference method, disc diffusion agar, for determination of general antimicrobial susceptibility or resistance. The disc diffusion interpretive result may be a guide for the clinician, and reflects the activity of the drug under the described test conditions, by taking into account other factors, such as drug pharmacology, pharmacokinetics, or bacterial resistance mechanisms. This allows categorisation of bacteria as “susceptible” (S), “intermediate” (I), or “resistant” ®. In addition, disc diffusion testing distributions can be used to define wild type or non-wild type bacterial populations. Although clinical interpretation of the disc diffusion zone of inhibition diameter value is beyond the scope of this part of ISO 20776, modifications of the basic method are required for certain antimicrobial agent - bacteria combinations to facilitate clinical interpretation. These modifications are included in a separate Annex of this document. It is necessary to compare other susceptibility testing methods (e.g. broth micro-dilution or diagnostic test devices) with this reference method for validation, in order to ensure comparable and reliable results.

Begin

2021-03-03

WI

00140148

Planned document number

DIN EN ISO 20776-3

Project number

06302076

Responsible national committee

NA 176 BR - Steering Committee of DIN Standards Committee Health Technologies  

Responsible european committee

CEN/TC 140 - In vitro diagnostic medical devices  

Responsible international committee

ISO/TC 212/WG 4 - Microbiology and molecular diagnostics  

Contact

Dipl.-Ing. (FH)

Elisabeth Beck

Alexander-Wellendorff-Str. 2
75172 Pforzheim

Tel.: +49 7231 9188-27
Fax: +49 7231 9188-33

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