Tel: (USA) (UK) Email:

Minimum Bactericidal Concentration (MBC) Assay

The minimum bactericidal concentration (MBC) is the minimum concentration of antibacterial agent required to kill a specific bacteria. MBC can be identified by determining the lowest concentration of antibacterial agent that reduces more than 99.9% of the viability of the initial bacterial inoculum. In antibacterial testing, MBC is a supplement to Minimum Inhibitory concentration(MIC). The MIC test shows the lowest level of antibacterial agent to inhibit the growth of microorganisms, while MBC shows the lowest level of antibacterial agent that causes the death of microorganisms. This means that even if a specific MIC exhibits a good inhibitory effect, inoculating bacteria on agar may still cause the proliferation of bacteria, because the antibacterial agent at this concentration will not cause the complete death of the bacteria. It is generally believed that MBC does not exceed four times the MIC, and the antibacterial agents is considered to have bactericidal effects. Since MBC is the lowest concentration of bactericidal drugs, it is measured in ug/mL. If the MBC of the tested drug against the tested microorganism is ≧32 times MIC, it can be determined that the microorganism has developed resistance to the tested drug. The MBC test allows the determination of the minimum reagent concentration necessary to achieve the bactericidal effect. It is worth noting that this method allows the antimicrobial agent to contact the tested organism for a longer time, about 18 hours. Therefore, the test result is the lowest concentration required to kill the test organism, including all other factors contributing to the bactericidal effect.

Minimum-Bactericidal-Concentration-Assay Figure 1. Minimum Inhibitory (MIC) and Minimum Bactericidal Concentration (MBC) Assays. (a) MIC assay plate layout for testing six different morpholino oligomers (MOs) in duplicate from 16 μM to 0.25 μM. 200 μL of MO is added in duplicate to row A and diluted by serial twofold dilutions (100 μL transfer) to row G. Row H contains the positive and negative controls. (b) Mock OD600 sample data for a single MO. The dashed box indicates the MIC of 4 μM (lowest dilution with mean OD600 ≤ 0.063). (c) Mock CFU/mL data for rows A-C in (b). The inoculum concentration was 5.2 × 105 CFU/mL. The MBC is defined as a 3-log reduction (≤5.2 × 102 CFU/mL), so the MBC is 16 μM.(Hong M. Moulton, et al. 2017)

Our Procedures

MBC detection uses a broth micro-dilution method similar to MIC. The detection process is as follows:

  • First, a pure culture of a specific microorganism is grown overnight, and then diluted to an appropriate concentration in a growth-supporting broth (usually Mueller Hinton broth).
  • After the compound to be tested is serially diluted, an equal volume of the designated microorganism is used to inoculate all the dilutions of the test product. The test tube or microtiter plate is then incubated at an appropriate temperature and duration.
  • Observations were made afterwards, where turbidity indicated the growth of microorganisms, and the lowest concentration of bacterial growth was not visually observed, that is, MIC.
  • To determine the MBC, a dilution representing the MIC and at least two more concentrated dilutions of the test product are plated and counted to determine the survival CFU/ml. Reach the lowest concentration that can inhibit the 99.9% activity of the tested bacteria, that is, MBC.

Our Advantages

  • Our MBC test is a reliable and relatively inexpensive detection tool, which can rank multiple antibacterial agents by potency for screening.
  • Our MBC test can be used to evaluate formulation problems, especially when the formulator suspects that the active ingredient is affected by other ingredients.
  • Ensure high efficiency and quality for MBC detection services
  • Competitive price in the market of MBC testing services
  • Ensure 24/7 online service
  • Timely result feedback

Our MBC Testing Services

  • Culturing to be detected standard test bacteria
  • Minimum Bactericidal Concentration testing
  • Statistics analysis experimental results

We combine infection and analytical expertise to provide our clients with the most powerful portfolio of antiviral and antimicrobial in vitro testing services. Facing an increasing demand for new antiviral and antimicrobial compounds for the treatment of infectious diseases, Creative Diagnostics can test these compounds in vitro to determine their potential efficacy in vivo models.


  1. Hong M. Moulton, et al. Morpholino Oligomers. Humana Press. 2017 ISBN 978-1-4939-6817-6.


Online inquiry


We Are Providing Our Clients Antiviral & Antibacterial Services

Having extensive knowledge in cell biology and the application of cell-based assays to benefit clients in the drug and vaccine development industry

Offering comprehensive solutions to drive your projects to completion

Delivering prompt quotations and competitive prices

Providing quality science and personalized customer service

Antiviral Services - Creative Diagnostics

Creative Diagnostics provides expertise in antiviral (or antibacterial) assays and cell-based antiviral (or antibacterial) compound screening to other biotechnology and pharmaceutical companies.

Contact us

  • Tel: (USA)
  • Tel: (UK)
  • Fax:
  • Email:

Copyright © Creative Diagnostics. All rights reserved.