Time-Kill Kinetics Assay – Antimicrobial Efficacy Test

Time-Kill Kinetics Test – Antimicrobial Efficacy Testing

Time-Kill Kinetics test, also known as the “suspension tests or suspension time kill analysis”, determines the time required by the antimicrobial agent to kill the challenge test microorganism. This test is utilized in microbiological studies to assess a test article’s in vitro antimicrobial activity in relation to time.

Basics of the Time-Kill Kinetics

When a client requests this service, our scientists will essentially perform the following steps: the undiluted and/or diluted test compound is introduced to a particular test bacteria at time zero. This mixture is grown at a set temperature and at specified time intervals, samples are taken out of the inoculum, put into a neutralization buffer, and then the microbe population is enumerated. The resulting data for the Time-Kill test is typically presented graphically, where the colony counts for each antimicrobial agent is plotted against the concentration tested at each time point when the subcultures were performed (usually at 0, 4, 8, 12, and 24 hours). Generally, in a Time-Kill test, a 3-log₁₀ reduction is considered the minimum level that would indicate a product has significant killing activity against a particular test microorganism. In contrast, in the minimal bactericidal concentration (MBC) test, bactericidal activity is defined as a 99.9% or greater killing efficacy at a specified time.

Time-Kill Kinetics Assay Log Reduction Graph

Time-kill Kinetics as a Log reduction with a test compound (CFU/mL) at 1 minute and 5 minutes.

Emery Pharma has successfully performed several Time-Kill studies for multiple clients in pharmaceutical industry. All testing follows the guidelines set by the Clinical & Laboratory Standards Institute (CLSI).