Agar and broth dilution methods to determine the minimal inhibitory concentration (MIC) of antimicrobial substances

  title={Agar and broth dilution methods to determine the minimal inhibitory concentration (MIC) of antimicrobial substances},
  author={Irith Wiegand and Kai Hilpert and Robert E. W. Hancock},
  journal={Nature Protocols},
The aim of broth and agar dilution methods is to determine the lowest concentration of the assayed antimicrobial agent (minimal inhibitory concentration, MIC) that, under defined test conditions, inhibits the visible growth of the bacterium being investigated. [] Key Method Agar dilution involves the incorporation of different concentrations of the antimicrobial substance into a nutrient agar medium followed by the application of a standardized number of cells to the surface of the agar plate.

Testing physiologically relevant conditions in minimal inhibitory concentration assays.

A platform that can be applied to the preparation of medium that mimics lung and wound exudate or blood conditions for the growth and susceptibility testing of bacteria, including ESKAPE pathogens is described.

Effects of Microplate Type and Broth Additives on Microdilution MIC Susceptibility Assays

The effects of several different plate types on microdilution broth MIC values for a set of antibiotics against Gram-positive and Gram-negative bacteria are examined, and it is found that nonspecific binding plates can replace the need for surfactant additives.

Determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using a novel dilution tube method

A novel DTM which is a modification of the ‘dilution method’ (DM) is hereby described for the determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC).

In Vitro Minimum Inhibitory Concentration (MIC) of Antibiotics Against Clinically Isolated Bacteria

Most of the time cephalosporine group antibiotics showed resistance against clinically isolated bacteria, but Ceftriaxone from this group with MIC range 0.5mg/L was compelled to the standard value of CLSI, so it is considered effective against this strain of E.coli.

Optimisation оf the microdilution method for detection of minimum inhibitory concentration values in selected bacteria

The results indicated that the ratio between optical density and cell numbers is not constant and use of the same OD for inoculums for all strains can therefore lead to misinterpretation of the MIC values.

A novel method for the dynamic analysis of antimicrobial effect

A rapid qualitative AST method is proposed, suitable for the prevention and control of infections caused by high resistant strains, and beneficial to promote the AST method for the development of new antibiotics.

Minimum Inhibitory Concentration (MIC) Of various synthetic and natural antimicrobial agents using E coli screened from VIT sewage treatment plant

The MIC Test helps to choose the more economic disinfectant from a given batch of disinfectants and can also be used to prepare a new anti microbial agent which has greater efficiency in lysing the microorganisms and is economic financially.

A Microtitre Plate Dilution Method for Minimum Killing Concentration Is Developed to Evaluate Metabolites-Enabled Killing of Bacteria by β-lactam Antibiotics

The MKC test was developed to accelerate the identification of compounds that promote antibiotic-mediated killing efficacy and was suitable for bactericidal antibiotics such as cephalosporins, penicillins and carbapenems and was proportional to the plate-counting test.

The Influence of Liquid Medium Choice in Determination of Minimum Inhibitory Concentration of Essential Oils against Pathogenic Bacteria

So far there is no internationally accepted, standardized method for MIC determination of natural substances such as essential oils (EOs). The aim of this study was to elucidate how much the MIC



Determination of minimum inhibitory concentrations.

  • J. Andrews
  • Medicine, Biology
    The Journal of antimicrobial chemotherapy
  • 2001
Standardized methods for determining minimum inhibitory concentrations and MBCs are described and like all standardized procedures, the method must be adhered to and may not be adapted by the user.

Tigecycline MIC Testing by Broth Dilution Requires Use of Fresh Medium or Addition of the Biocatalytic Oxygen-Reducing Reagent Oxyrase To Standardize the Test Method

Results suggested that the activity of tigecycline was affected by the amount of dissolved oxygen in the media, and the use of fresh MHB or supplementation with Oxyrase resulted in a more standardized test method for performing MIC tests with tigECYcline.

Comparison of the Etest with a conventional agar dilution method in evaluating the in vitro activity of moxifloxacin.

Compared the MICs of moxifloxacin determined by two methodologies: according to recommendations of the British Society for Antimicrobial Chemotherapy (BSAC), and with the Etest adapted for use in the UK.


  • W. E. Wick
  • Biology, Medicine
    Journal of bacteriology
  • 1964
Experimental evidence is presented to indicate the necessity for re-evaluation of results obtained from in vitro sensitivity testing methods for some antibiotics.

The Effects of Environmental Conditions on the In Vitro Activity of Selected Antimicrobial Agents Against Escherichia coli

The results of this in vitro study might provide insight into the effects of local in vivo environmental conditions on several classes of antimicrobial agents.

European harmonization of MIC breakpoints for antimicrobial susceptibility testing of bacteria.

Mic breakpoints are used either directly, as in MIC determination and ‘breakpoint’ susceptibility testing methods in broth or agar, or indirectly when converted into inhibition zone diam-eters in disc diffusion techniques.

Effect of Calcium and Magnesium Ions on the Susceptibility of Pseudomonas Species to Tetracycline, Gentamicin Polymyxin B, and Carbenicillin

Susceptibility tests on Pseudomonas species probably should be done with Muller-Hinton broth supplemented with physiological concentrations of calcium and magnesium to better approximate the in vivo activity of these antibiotics.

Cefepime, Piperacillin-Tazobactam, and the Inoculum Effect in Tests with Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae

Suggestions that cefepime may be a less-than-reliable agent for therapy of infections caused by extended-spectrum β-lactamase (ESBL) strains are supported.