Related Experiment Video
Updated: Feb 28, 2026
Deferred Growth Inhibition Assay to Quantify the Effect of Bacteria-derived Antimicrobials on Competition
Published on: September 3, 2016
An Experimental Framework for Quantifying Bacterial Tolerance
Asher Brauner1, Noam Shoresh2, Ofer Fridman1
1The Racah Institute of Physics and the Center for NanoScience and NanoTechnology, Edmond J. Safra Campus, The Hebrew University, Jerusalem, Israel.
Abstract:
Antibiotic tolerance and persistence are often associated with treatment failure and relapse, yet are poorly characterized. In distinction from resistance, which is measured using the minimum inhibitory concentration metric, tolerance and persistence values are not currently evaluated in the clinical setting, and so are overlooked when a course of treatment is prescribed. In this article, we introduce a metric and an automated experimental framework for measuring tolerance and persistence. The tolerance metric is the minimum duration for killing 99% of the population, MDK99, which can be evaluated by a statistical analysis of measurements performed manually or using a robotic system. We demonstrate the technique on strains of Escherichia coli with various tolerance levels. We hope that this, to our knowledge, new approach will be used, along with the existing minimum inhibitory concentration, as a standard for the in vitro characterization of sensitivity to antimicrobials. Quantification of tolerance and persistence may provide vital information in healthcare, and aid research in the field.
Insights
This study introduces a new metric, minimum duration for killing 99% (MDK99), to measure antibiotic tolerance and persistence. This advancement aims to improve antimicrobial sensitivity testing in clinical settings.
Area of Science:
- Microbiology
- Pharmacology
- Clinical Science
Background:
- Antibiotic tolerance and persistence are linked to treatment failure but are not well-understood or clinically measured.
- Current clinical practice primarily relies on minimum inhibitory concentration (MIC) for antibiotic sensitivity, overlooking tolerance and persistence.
Purpose of the Study:
- To introduce a novel metric and experimental framework for quantifying antibiotic tolerance and persistence.
- To establish a standardized method for evaluating antimicrobial sensitivity beyond traditional resistance markers.
Main Methods:
- Development of a new metric: minimum duration for killing 99% of the population (MDK99).
- Implementation of an automated experimental framework for measuring MDK99, adaptable for manual or robotic systems.
- Demonstration of the technique using various strains of Escherichia coli.
Main Results:
- Successfully demonstrated a method for measuring antibiotic tolerance and persistence using the MDK99 metric.
- Validated the experimental framework on Escherichia coli strains exhibiting diverse tolerance levels.
- Provided a quantifiable measure for tolerance and persistence, distinct from MIC.
Conclusions:
- The MDK99 metric and associated framework offer a new standard for in vitro antimicrobial sensitivity characterization.
- Quantifying tolerance and persistence can provide crucial data for healthcare and advance research in antimicrobial stewardship.
- Integrating MDK99 alongside MIC may lead to more effective antibiotic treatment strategies.
