Microorganism Separation via Density Gradient Centrifugation
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Solution Overview
Problem
Current methods for detecting and identifying microorganisms in blood cultures are slow, labor-intensive, and prone to contamination, especially in polymicrobic bacteremia cases, where multiple pathogens are present, leading to delayed diagnosis and increased mortality.
Innovation Solution
A method involving selective lysis of non-microorganism cells, layering the sample on a density cushion, and centrifugation to separate microorganisms into enriched layers, followed by spectroscopic interrogation for rapid characterization and identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If traditional automated phenotypic ID tests are used with microorganisms isolated from positive blood culture bottles, then identification speed is improved, but reliability deteriorates due to interference from media and blood products
Solution Approach 1:
The patent extracts microorganisms from the complex blood culture medium through centrifugation and washing steps, removing interfering substances while retaining the target organisms for spectroscopic analysis. This separation eliminates the reliability issues caused by media and blood product interference.
Solution Approach 2:
The patent introduces spectroscopic methods as an intermediary technique that can analyze microorganisms directly from blood cultures without requiring traditional culture isolation. This intermediary approach bypasses the reliability problems of phenotypic tests while maintaining rapid identification capabilities.
2Loss of time
If spectroscopic methods are used to identify microorganisms directly from blood culture broth, then identification speed is improved, but measurement precision deteriorates due to interference from fluorescent and absorptive compounds
Solution Approach 1:
The patent extracts microorganisms from the interfering blood culture medium through centrifugation, separating the target organisms from fluorescent and absorptive compounds. This extraction preserves the speed advantage of direct spectroscopy while eliminating measurement precision problems.
Solution Approach 2:
The patent segments the analysis into distinct steps: first separating microorganisms from the complex medium via centrifugation, then performing spectroscopic analysis on the purified organisms. This segmentation allows each step to optimize for its specific function without interference.
3Measurement precision
If manual phenotypic tests are used for microorganism identification, then measurement precision is improved, but productivity deteriorates due to labor-intensive procedures
Solution Approach 1:
The patent replaces manual phenotypic testing with automated spectroscopic analysis. The spectroscopic system automatically acquires and analyzes spectral data, eliminating labor-intensive manual operations while maintaining or improving identification precision through objective, quantitative measurements.
Solution Approach 2:
The patent implements a self-service system where the spectroscopic instrument automatically performs measurement, data processing, and identification without requiring manual intervention. This automation maintains measurement precision while dramatically increasing testing throughput and productivity.
4Loss of time
If rapid identification methods are used within the first few hours after positive culture result, then loss of time is reduced, but device complexity increases due to specialized equipment requirements
Solution Approach 1:
The patent employs spectroscopic instruments that can perform multiple functions: separating microorganisms via centrifugation, acquiring spectral data, processing measurements, and providing identification. This multi-functionality reduces the need for multiple specialized devices while achieving rapid identification.
Solution Approach 2:
The patent combines several functions into a single integrated system: sample preparation, spectroscopic measurement, data analysis, and identification. This merging of functions reduces device complexity compared to using separate specialized equipment for each step while maintaining rapid diagnostic capability.
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
Enables rapid identification of multiple microorganism species within 120 minutes, reducing the risk of handling infectious materials and providing clinically relevant information quickly, thus improving patient outcomes in septicemia and other infections.
Implementation Method 1
centrifugation to separate microorganisms into enriched layers
Implementation Method 2
layering the sample on a density cushion
Implementation Method 3
spectroscopic interrogation for rapid characterization and identification
Data Source
AI summary
The present invention is directed to a method for separating, characterizing and/or identifying microorganisms in a test sample. The method of the invention comprises an optional lysis step for lysing non-microorganism cells that may be present in a test sample, followed by a subsequent separation step. The method may be useful for the separation, characterization and/or identification of microorganisms from complex samples such as blood-containing culture media. The method may also be useful for the physical separation and/or enrichment of two or more different or individual microorganism species contained in a mixed test sample. The invention further provides for spectroscopic interrogation of the separated microorganism sample(s) to produce measurements of the microorganism and characterizing and/or identifying the microorganism(s) in the sample using said spectroscopic measurements.