Antimicrobial Susceptibility Test Using Automated Cell Image Analysis
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Solution Overview
Problem
Conventional antimicrobial susceptibility tests (AST) are time-consuming, unreliable, and fail to observe individual cell changes under antimicrobial agents, leading to inaccurate results due to their focus on growth presence or absence rather than morphological changes.
Innovation Solution
An AST method analyzing changes in morphology and growth patterns of microbial cells under different antimicrobial concentrations, using an automated cell image analysis system to classify changes into dividing, no-change, filament formation, and swelling formation, determining susceptibility based on these classifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional AST methods are used to observe growth presence or absence, then the test can be performed with simple equipment, but the test time is long (16-24 hours) and reliability is low
Solution Approach 1:
The patent segments the observation focus from population-level growth to individual cell morphology. Instead of observing bulk growth (conventional method), the invention observes and analyzes changes in individual bacterial cells' morphology, size, and shape under antimicrobial agents, enabling earlier and more reliable detection of susceptibility.
Solution Approach 2:
The patent replaces the mechanical/conventional turbidity measurement method with an optical imaging and image analysis system. By using microscopy to capture individual cell images and analyzing morphological changes through image processing algorithms, the system achieves faster and more reliable AST results without requiring long incubation times.
2Measurement precision
If conventional AST methods are used to measure turbidity or absorbance, then the test is simple to perform, but it cannot observe individual cell changes and requires large numbers of cells
Solution Approach 1:
The patent applies segmentation by transitioning from population-level measurement to individual cell analysis. The system captures images of individual bacterial cells and analyzes their morphological characteristics separately, enabling precise observation of cell-level changes without requiring large cell numbers or complex statistical aggregations.
Solution Approach 2:
The patent introduces an intermediary image analysis system that bridges the gap between simple microscopy and complex quantitative analysis. The image processing algorithms act as intermediaries to automatically extract morphological features from individual cell images, providing precise measurements without requiring manual intervention or overly complex experimental designs.
3Productivity
If solid medium is used for AST, then the KB-test can be performed, but the number of samples per plate is limited and many plates are required for tens of antimicrobial agents
Solution Approach 1:
The patent uses liquid culture media instead of solid agar plates, creating a virtual replication space where multiple antimicrobial agents and samples can be simultaneously cultured in a single liquid medium. This eliminates the physical limitation of solid plate capacity and allows high-throughput testing of numerous antimicrobial agents against multiple bacterial strains in parallel.
Solution Approach 2:
The patent transitions from two-dimensional solid plate culture to three-dimensional liquid culture system. By using liquid media, the system can accommodate far more samples and antimicrobial agents without the spatial constraints of solid plates, effectively adding a dimension to the testing capacity and enabling high-throughput AST.
4Reliability
If conventional AST methods are used, then the test environment is simple, but the results differ largely from real phenomena in the human body
Solution Approach 1:
The patent changes the observation parameters from bulk growth parameters (turbidity, absorbance) to individual cell morphological parameters (size, shape, structure). This parameter change allows the detection of early cellular responses to antimicrobial agents that reflect actual clinical behavior, improving the reliability of AST results while maintaining relatively simple test conditions.
Data Source
AI summary
Provided are a rapid antimicrobial susceptibility test, based on an analysis of changes in morphology and growth pattern of a microbial cell under different concentrations of various antimicrobial agents, and an automated cell image analysis system therefor. The antimicrobial susceptibility test is rapidly performed based on an analysis of changes in morphology and growth pattern of a microbial cell under different concentrations of various antimicrobial agents, and this makes it possible to obtain highly reliable test results faster by six to seven times than the standard method recommended by Clinical and Laboratory Standards Institute (CLSI).