Minimum Inhibitory Concentration Testing White Paper

Antimicrobial susceptibility tests are performed, typically in clinical microbiology laboratories, to provide an in vitro measurement of susceptibility and resistance. This is performed by determining the concentration of drug required to inhibit an organism to a specific degree, termed the Minimum Inhibitory Concentration (MIC). Ideally, this then provides a reliable prediction of patient outcome relative to therapy. As more therapeutic choices become available, the value of detecting antimicrobial resistance becomes ever more important and the need for optimisation of the antimicrobial agent increases.

Minimum inhibitory concentration testing, although typically used in a clinical setting can also be applied to products within the healthcare industry. The screening for alternatives to antibiotics is of increasing importance within the pharmaceutical and healthcare industries. In addition, synergies between certain new alternative antimicrobial compounds have also shown promising results.

MIC Testing is a standard method used to determine the in vitro susceptibility testing of bacteria and/or yeasts that grow aerobically. There are a number of available methodologies for susceptibility testing including Broth Microdilution, Disk diffusion and Gradient diffusion. The method developed at Lucideon involves the use of the ‘Broth Microdilution Method’, so called because it involves the use of small volumes of broth dispensed in sterile, plastic microdilution trays. As one of the first methodologies developed, it has historically been the most commonly used technique. It is therefore often termed the ‘Gold Standard’ of susceptibility testing.