Pioneering diagnostics

Minimum Inhibitory Concentration of an Antibiotic

We have two complementary systems to perform one of the most important tests for diagnosing and treating infectious diseases.


Why it’s important

The Minimum Inhibitory Concentration (MIC) is a measure of the sensitivity of microbes to antibiotics or antifungals (antimicrobials). Organisms are tested for growth in various concentrations of antibiotic. This allows microbiologists to see which concentration (MIC) of antimicrobial will be effective against the pathogen.


  • The MIC of an antibiotic is a determining factor in choosing or refining patient treatment.
  • It is used for determining treatment for patients suffering from infections such as sepsis, pneumonia, meningitis, endocarditis or osteomyelitis or managing the treatment of high-risk patients such as those suffering from cystic fibrosis or immunocompromised individuals.

Our product offering

  • bioMérieux’s VITEK® 2 system for organism identification and antimicrobial susceptibility testing (ID/AST) performs automated MIC testing covering the vast majority of testing needs.
  • bioMérieux's Etest® is a diffusion technique on agar plate allowing the very simple measurement of an antibiotic's Minimum Inhibiting Concentration (MIC):
    • Etest complements VITEK 2 Technology by allowing:
      • testing newly issued antibiotics that are not available on VITEK 2 cards,
      • testing rare or slow-growing organisms that can’t be tested by primary AST methods,
      • detecting or confirming antimicrobial resistance,
      • meeting the need for extended- range MICs to guide and refine treatment of critically ill patients.

What is Etest?

The Etest strip comprises a gradient of antibiotics increasing from a low concentration at one end to a high concentration at the other end.
It is placed on a Petri plate inoculated with bacteria and incubated overnight.
The MIC is read on the Etest strip at the point where bacterial growth stops.