Automated Sample Suspension Inoculation for MALDI and AST
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Solution Overview
Problem
Current methods for identifying microorganisms in biological samples and determining their antimicrobial susceptibility are labor-intensive and require separate sample preparations, making it difficult to efficiently link identification and susceptibility testing results.
Innovation Solution
An automated method that uses a common sample suspension for both MALDI identification and AST testing, where the turbidity of the suspension is measured and adjusted through dilution or concentration protocols to ensure accurate and efficient inoculation of samples into MALDI plates and AST broth tubes, eliminating the need for standardizing turbidity to a McFarland value prior to inoculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate sample preparations are performed for identification and antimicrobial susceptibility testing, then accurate results can be obtained for both tests, but the workflow becomes labor-intensive and time-consuming
Solution Approach 1:
The patent merges the sample preparation steps for identification and AST into a single common suspension preparation process. The system uses one automated nephelometry measurement and one standardized suspension to serve both testing purposes, eliminating the need for separate preparation workflows while maintaining the reliability of both tests through controlled turbidity measurement and automated inoculation.
Solution Approach 2:
The common suspension serves multiple functions: it is used for both microorganism identification and antimicrobial susceptibility testing. The system design allows a single prepared suspension to be distributed to multiple test modules, making the preparation process universal and eliminating redundant steps while ensuring both tests receive appropriately prepared samples.
2Reliability
If separate sample preparations are performed for identification and antimicrobial susceptibility testing, then each test can be optimized independently, but the overall process complexity and equipment requirements increase
Solution Approach 1:
The patent combines multiple preparation functions into a single integrated system. One nephelometer performs turbidity measurements for both identification and AST optimization, and one automated inoculation system distributes the common suspension to multiple test modules, reducing equipment complexity while maintaining test optimization through software-controlled parameters.
Solution Approach 2:
The system employs universal equipment that performs multiple functions: the nephelometer measures turbidity for both test types, and the automated inoculation system serves both identification and AST workflows. This multi-functional design reduces the total number of specialized devices needed while maintaining optimal conditions for each test through programmable parameters.
3Manufacturing precision
If standardization to McFarland value is performed prior to inoculation, then accurate inoculum concentration is achieved, but additional time and equipment are required
Solution Approach 1:
The patent replaces the traditional mechanical McFarland standardization process (requiring visual comparison and manual adjustment) with an automated optical nephelometry system. The nephelometer objectively measures turbidity and provides real-time feedback for automated dilution or concentration decisions, achieving precise inoculum concentration without manual intervention or additional standardization steps.
Solution Approach 2:
The system implements feedback control by measuring the turbidity of the common suspension with a nephelometer and using this measurement to automatically determine the appropriate inoculation volume or required dilution/concentration. This closed-loop feedback mechanism ensures accurate inoculum concentration is achieved directly during the single preparation process, eliminating time-consuming manual standardization steps.
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
This approach simplifies the workflow, reduces equipment intensity, and ensures accurate sample inoculation, leading to reproducible AST results and efficient patient care by linking identification and susceptibility testing directly.
Implementation Method 1
The turbidity of the sample is then measured with a nephelometer
Implementation Method 2
If the measured turbidity is determined to be outside of the predetermined range, then the sample suspension is diluted or concentrated
Data Source
AI summary
An automated method for preparing a sample suspension. The sample suspension can be used for both MALDI and antimicrobial susceptibility (AST). A suspension is prepared, and a portion of that suspension is removed for a first analysis (e.g. MALDI), leaving a remaining volume. The turbidity of the remaining volume is measured. If the turbidity is below a first threshold, the suspension is not used for a second analysis (e.g. AST) and is subjected to a concentration protocol to raise the turbidity of the suspension. If the turbidity is within a predetermined range, a volume of the suspension is calculated that will deliver a predetermined amount of sample to a vessel for the second analysis. If the turbidity of the suspension is above the predetermined range, and the suspension has not been diluted a predetermined number of times, the suspension is diluted according to a dilution protocol.