A Zone of Inhibition Test (also known as the Kirby-Bauer Test, Antimicrobial Susceptibility Test, Disk Diffusion Test or Agar Diffusion Test) is a quick way to assess the antimicrobial activity of a material or solution in relation to a target microorganism. This is a test that has been used for years and was first developed in the 1950’s and then standardized by the World Health Organization in 1961. Typically the test is a qualitative test which is commonly used in the clinical setting to assess an antibiotic’s effect on a selected microorganism. As antimicrobial embedded products have entered the market place, the Zone of Inhibition test is now being used throughout industry to assess the inhibitory nature against an array of different microorganisms. This test performs best if the antimicrobial is able to leach out of the material. It is a quick analysis to screen an antimicrobial product for inhibitory activity against a panel of different microorganisms.
Materials tested typically include leachable antimicrobial which has been embedded in plastics, textiles, solids, surfaces, liquids, gels, etc. as well as antibiotic solutions. The Zone of Inhibition test is a common and basic microbiological test commonly used throughout the medical device and pharmaceutical industries. Guidance for the susceptibility test from a clinical perspective may be found in the CLSI supplement M100. As a well-known contract laboratory in both the Pharmaceutical and Medical Device industries, we are highly experienced in performing Zone of inhibition testing using a large variety of microorganism.
- CLSI Supplement M100 “Performance Standards for Antimicrobial Susceptibility Testing”