Thermostable Luciferase Assay for Rapid Bactericidal Screening
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Solution Overview
Problem
Current methods for screening bactericidal compounds and determining bacterial sensitivity are slow, unreliable, and lack sensitivity, particularly when testing stationary phase or biofilm bacteria, and often require physical or chemical stress that alters results.
Innovation Solution
A real-time luciferin-luciferase assay using thermostable luciferase to measure ATP efflux from live bacteria exposed to candidate compounds, avoiding physical and chemical stress, allowing rapid and reliable detection of bactericidal activity and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If classical growth inhibition assays are used to screen bactericidal compounds, then the method can detect bacterial growth inhibition, but the test takes many hours (e.g., 20 hours) before results are obtained
Solution Approach 1:
The patent replaces the mechanical/growth-based detection system (agar plates, visual inspection of growth inhibition) with a biochemical detection system (ATP bioluminescence assay). The luciferin-luciferase system converts ATP into light signals, enabling rapid detection of bacterial cell lysis and bactericidal activity without waiting for growth inhibition to manifest visually.
Solution Approach 2:
The patent changes the detection parameter from bacterial growth inhibition (visual, time-dependent) to ATP concentration (biochemical, rapid). By measuring ATP levels in the supernatant using bioluminescence, the method transitions from a slow phenotypic observation to a fast biochemical measurement, reducing test time from hours to minutes.
2Adaptability or versatility
If stationary phase or biofilm bacteria are tested using conventional methods, then the method can assess drug efficacy against difficult-to-kill bacteria, but most assays cannot be performed on these bacterial forms
Solution Approach 1:
The patent creates a universal detection system that works across multiple bacterial states (exponential phase, stationary phase, biofilm) and multiple bacterial forms (planktonic, adherent). The ATP bioluminescence assay detects cell lysis regardless of bacterial growth state, making the method applicable to all clinically relevant bacterial forms without requiring separate assays for each.
Solution Approach 2:
The patent uses ATP as an intermediary marker to detect bactericidal activity. Instead of directly observing bacterial growth or morphology changes, the method measures ATP release from lysed cells. This intermediary approach allows detection of cell death in stationary phase and biofilm bacteria without requiring direct observation of their specific morphological characteristics.
3Measurement precision
If osmotic shock is applied to bacteria to facilitate ATP release detection, then the method can enhance signal detection, but the physical stress alters bacterial membranes and causes non-antibiotic driven ATP release
Solution Approach 1:
The patent applies a preliminary protective measure by using gentle handling and avoiding osmotic shock. The method incorporates control experiments that compensate for any minor stress effects, and the assay conditions are designed to minimize physical stress on bacteria before ATP measurement, preventing false-positive signals from non-antibiotic driven ATP release.
4Ease of manufacture
If centrifugation is used to remove bacteria from sample before ATP measurement, then the method can separate cells from supernatant, but the process alters bacterial cell walls and causes artificial ATP release
Solution Approach 1:
The patent extracts only the necessary component (supernatant containing released ATP) while leaving the cells intact. By carefully separating the supernatant from the cell pellet without subjecting cells to harsh centrifugation, the method obtains ATP-rich supernatant while minimizing cell wall damage and artificial ATP release that would compromise measurement accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method provides rapid, sensitive, and reliable screening of bactericidal compounds and bacterial sensitivity, applicable to various bacterial strains and forms, including biofilms, with results obtained in minutes rather than hours, suitable for high-throughput screening.
Implementation Method 1
adding a mixture of luciferin and a thermostable luciferase to said test bacterial sample(s)... measuring bioluminescence in real-time
Data Source
Figure 1
Figure 2A~2D
Figure 3A
AI summary
The present invention relates to a method for screening compounds for bactericidal activity using thermostable luciferase and based on a real-time bioluminescence measurement. The present invention further relates to a method for determining the sensitivity of a bacterial sample originating from a subject suffering from a bacterial infection to a group of known antibiotics and to a method for assessing the minimum inhibitory concentration (MIC) of a bactericidal compound.