Identification and antibiotic susceptibility testing

An integral part of clinical decision-making, identifying bacteria and assessing their response to antibiotics is increasingly important due to the rise in multidrug resistant bacteria.

Every day, doctors use identification (ID) and antibiotic susceptibility test (AST) results to determine the antibiotic treatment that is most appropriate for the infectious agent, the site of infection and the patient. These test results also make it possible to track any changes in bacterial resistance to antibiotics.

Bacterial identification

This test identifies the pathogen responsible for an infection.

It must be quick and reliable to:

  • improve patient care,
  • improve management of outbreaks,
  • fight health-care associated infections.

Antibiotic susceptibility testing

Antibiotic susceptibility testing determines the susceptibility of a bacterial strain to a panel of antibiotics.

  • The microorganism is placed in contact with the antibiotics and the test reveals if the microorganism will grow or not in the presence of the antibiotics.
  • This information is reported to the clinician as the Minimum Inhibitory Concentration (MIC), the measure of a microorganism’s susceptibility or resistance to an antibiotic.
  • Antibiotic susceptibility testing is used to detect bacteria’s mechanisms of resistance to antibiotics.

Clinicians use antibiotic susceptibility test results to help determine the most appropriate treatment for the infection and the individual patient.

The challenge

Bacterial identification and antibiotic susceptibility testing play an essential role in patient care and the control of antibiotic resistance mechanisms by:

  • Indicating which antibiotics are most likely to treat an infection,
  • Reducing the empirical prescription of "broad-spectrum" antibiotics, which are partly responsible for the rapid increase in antibiotic resistance,
  • Avoiding the unnecessary prescription of antibiotics in order to reduce healthcare costs.

ID/AST tests also play a role in epidemiological monitoring, making it possible to track changes in antimicrobial resistance patterns in healthcare settings.

Our solutions


  • Identification (ID)

bioMérieux, world leader in bacterial identification, has the broadest offer of automated and manual solutions.

The API gallery range revolutionized microbiology when it was launched on the market in 1969. This highly-trusted method allows the phenotype identification of all types of microorganisms (approximately 700 bacteria and yeast).

bioMérieux is the market leader in automated bacterial identification and antibiotic susceptibility testing with its VITEK® range, which identifies routine microorganisms as well as the more rare ones (over 300 microorganisms).

  • Results can be obtained as quickly as 3 to 7 hours thanks to the combination of analysis software and an original, miniaturized consumable, the VITEK® 2 card, which is available for a wide range of antibiotics.
  • For the more complex microorganisms, VITEK 2 can be combined with complementary manual methods: the  API® range for identification, RAPIDEC® CARBA NP to detect resistance, and ETEST® for antibiotic susceptibility testing.

bioMérieux also uses the MALDI-TOF mass spectrometry method, which is fully integrated with bioMérieux's VITEK® MS platform, making it possible to identify a microorganism’s genus and species in just a few minutes.


  • Antibiotic susceptibility testing (AST)

Antibiotic susceptibility testing (AST) is essential to adapt the patient’s antibiotic treatment and fight antibiotic resistance.

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

It is used to determine treatment for patients with infections such as sepsis, pneumonia, meningitis, endocarditis or osteomyelitis and for managing the treatment of high-risk patients such as patients with cystic fibrosis and immunocompromised individuals.

bioMérieux has two complementary systems to perform antibiotic susceptibility testing, considered to be one of the most important tests for diagnosing and treating infectious diseases.

  • Our VITEK® 2 system for the identification of bacteria and antimicrobial susceptibility testing (ID/AST) performs automated MIC testing covering the vast majority of testing needs. As a pioneer in the field of resistance interpretation software, bioMérieux has integrated the Advanced Expert System (AES™), reference in its field, into the VITEK® 2 platform.
  • ETEST® is a technique allowing the very simple measurement of an antibiotic's Minimum Inhibitory Concentration (MIC):
    • ETEST® complements VITEK® 2 technology by allowing:
      • Testing of rare or slow-growing bacteria that cannot be tested using primary AST methods,
      • Detecting or confirming antimicrobial resistance,
      • Meeting the need for extended-range MICs to guide and refine treatment of critically ill patients.