Somatic Cell Digestion Agent for Blood Culture Lysis
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Solution Overview
Problem
Current methods for isolating microorganisms from positive blood cultures, such as those involving Streptococcus pneumoniae, face challenges due to autolysin activation and the use of harsh detergents that compromise microbial viability, leading to inconsistent identification and inadequate samples for downstream testing like MALDI-TOF/MS and AST.
Innovation Solution
A method using a Somatic Cell Digestion Agent (SDA) like Nonoxynol-9 in a lysis buffer to efficiently lyse blood cells while maintaining microbial viability, allowing for effective isolation and identification of microorganisms, including challenging species like Staphylococcus epidermidis, by achieving higher MALDI scores and enabling multiple downstream testing from a single sample.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If harsh detergents are used to lyse blood cells, then blood cell lysis efficiency is improved, but microbial viability deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the lysis buffer by replacing harsh detergents with milder alternatives such as saponin, Tween 20, and Triton X-100 at optimized concentrations. This parameter modification allows effective blood cell lysis while preserving microbial viability, resolving the contradiction between lysis efficiency and microbial survival.
Solution Approach 2:
The patent employs a composite lysis buffer system combining multiple gentle detergents (saponin, Tween 20, Triton X-100) with salts and buffers. This composite approach synergistically enhances blood cell lysis efficiency while maintaining microbial integrity, overcoming the limitation of single-component harsh detergents.
2Manufacturing precision
If sub-culturing is performed to isolate microorganisms, then microbial purity is improved, but processing time deteriorates
Solution Approach 1:
The patent performs preliminary lysis of blood cells and removal of cellular debris before microbial isolation, using optimized lysis buffers and centrifugation. This preliminary purification step reduces the need for extensive sub-culturing, achieving microbial purity faster and reducing overall processing time from 72 hours to a significantly shorter duration.
Solution Approach 2:
The patent extracts and removes blood cell components and cellular debris from the sample using selective lysis and centrifugation, concentrating the microorganisms in a purified state. This extraction approach achieves microbial purity without requiring multiple sub-culturing steps, thereby reducing processing time.
3Speed
If liquid separation methods with lysis buffers are used, then isolation speed is improved, but microbial integrity deteriorates
Solution Approach 1:
The patent modifies the lysis buffer parameters by using mild detergents at optimized concentrations and controlling incubation conditions, enabling rapid blood cell lysis and microbial isolation while preserving microbial integrity. This allows quick processing suitable for time-sensitive applications like MALDI-TOF/MS and AST testing.
Solution Approach 2:
The patent replaces harsh mechanical or chemical lysis methods with a optimized chemical lysis system using gentle detergents. This substitution achieves rapid isolation speed while maintaining microbial integrity, making the process compatible with downstream applications requiring viable microorganisms.
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 a rapid and efficient means to isolate viable microorganisms, achieving higher MALDI scores and ensuring the integrity of microorganisms for identification and antimicrobial susceptibility testing, thereby reducing processing time and improving diagnostic accuracy.
Implementation Method 1
contacting a sample comprising blood cells and at least one microorganism with a lysis buffer to generate a treated sample, wherein the lysis buffer comprises a Somatic Cell Digestion Agent (SDA) capable of lysing blood cells in the sample
Data Source
AI summary
Disclosed herein include methods, compositions, and kits suitable for use in processing a sample comprising blood cells and at least one microorganism. In some embodiments, the method comprises contacting the sample with a lysis buffer to generate a treated sample. The lysis buffer can comprise a Somatic Cell Digestion Agent (SDA) capable of lysing blood cells in the sample. In some embodiments, the at least one microorganism remains intact and/or viable in the presence of the SDA.