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Antimicrobial testing

In vitro assessment of the ability of a compound to kill or inhibit growth of bacteria is important during drug development in order to select and optimize leads, as well as to predict/estimate potential in vivo efficacy. Zenit science offers assays that determine the minimum inhibitory concentration (MIC), minimum bacteriocidal concentration (MBC) and kinetics of bacteriocidal activity (the time-kill assay).

Zenit Science offers

Our commitment to quality ensures reliable and reproducible data generated by experienced molecular biology scientists.

All assays are optimized to fit microtiter formats, requiring only low amounts (0.1 ml) of your precious samples material.

When choosing our standard package solutions prices are readily visible in the ordering system.

We ensure a rapid turnaround to faciliate efficient identification of promising leads early in drug development – One week following compound delivery.

Cost-effective standard packages can be directly ordered using our online system. We also offer tailoring of assays according to specific customer needs.

Antimicrobial Efficacy Assays

Standard assays

Assessment of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of your sample against a panel of bacterial strains (consisting of E. coli, S. aureus, P. aeruginosa, K. pneumoniae).

Assessment of the kinetics of bactericidal activity (time-kill) against either Escherichia coli or Staphylococcus aureus. Survival is measured after 0, 0.5, 2, 5 and 24 hours.

Colistin is included as internal control in the assays, and all samples are run in triplicate to ensure reliability and statistical power.

Customized Assays

Other strains, incubation timepoints, or medias than described above are available upon request.

MIC and MBC determination


The minimum inhibitory concentration (MIC) assay is used to determine the lowest concentration at which a compound inhibits growth of a particular bacterium in a particular medium. In order to build a more complete picture about breadth of activity, the assay is typically repeated for a several of bacterial strains. Zenit Science follows the EUCAST guidelines for susceptibility testing, using Mueller-Hinton II Broth as standard medium.

We also offer customization of the assay according to specific customer needs. Examples are assessment of alternative bacterial strain (sensitive or antibiotic resistant), additional time points of assessment, or the use of alternative (non-standard) growth medium [1] during the experiment.


The minimum bactericidal concentration (MBC) assay is used to determine the lowest concentration at which a compound kills a particular bacterium in a particular medium. Together with the MIC assay one can determine whether the effect of the compound is growth inhibitory or bactericidal.

The raw data showcases the minimal variability in MIC determination at Zenit Science, as evidenced by the growth assessment (optical density/OD) of Escherichia coli following treatment with varying doses of Colistin.

The time-kill kinetic assay

The time-kill kinetic assay is used to determine the rate at which the bacteria are killed upon exposure to your sample/compound. This assessment is a starting point in understanding the kinetics of infection elimination during treatment. The read-out of the assay is a graph showing the number of surviving bacterial cells versus duration of exposure to compound.

Zenit Science offers a package service which includes the assessment of time-kill kinetics of your compound against either Escherichia coli (gram negative bacterium) or Staphylococcus aureus (gram positive bacterium). Survival is measured after 0, 0.5, 2, 5 and 24 hours.

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