Minimum Bactericidal Concentration

Minimum Bactericidal Concentration (MBC) Test Method

• Overnight grown culture of test microorganisms is diluted in growth-supporting broth (Mueller Hinton Broth) between 1 x 10^5 and 1 x 10^6 cfu/ml.
• Serial dilutions of antimicrobial test compound are made.
• All the dilutions of test compound are inoculated with an equal volume of test microorganisms.
• These dilutions are further transferred into 96-well Microtiter Plates. In parallel, a growth control (bacterial suspension without any antimicrobial agent) and sterile control (media without bacteria where no bacterial growth is observed after incubation) are also used in the test procedure. 
• Microtiter plate is further incubated at a specific temperature and duration.
• After incubation bacterial growth is observed,  turbidity indicates the growth of the microorganism, and lowest concentration of dilution with no turbidity or visible growth is referred as MIC (Minimum Inhibitory Concentration).
• 2-3 dilutions showing MIC are plated on a suitable growth medium and incubated to determine the viable cells.
• The lowest concentration that shows 99.9% reduction of the tested bacteria is MBC.