Mycobacterium Detection via Crystal Violet Staining and Selective Pretreatment
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Solution Overview
Problem
Current methods for detecting and differentiating Mycobacterium, particularly non-tuberculous mycobacterium (NTM), are limited by slow growth rates, contamination issues, and the need for harsh pretreatment reagents, leading to lengthy, expensive, and inefficient diagnostics.
Innovation Solution
A novel growth medium, MYChrOme, containing high concentrations of crystal violet and a pretreatment method, MYCOn, using sodium dodecyl sulfate and glycine hydrochloride, which selectively enhances the detection of Mycobacterium by inhibiting the growth of other bacteria, allowing for rapid identification of Mycobacterium through distinct colony coloration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard growth media (LJ, R2A, Middlebrook) are used for Mycobacterium detection, then the method is well-established and easy to perform, but the media offer little differentiation and selection for Mycobacterium among contaminated samples
Solution Approach 1:
The patent employs crystal violet dye that selectively stains Mycobacterium colonies purple while other bacteria remain unstained or show different coloration. This color-based differentiation allows immediate visual identification of Mycobacterium colonies on the growth media, directly resolving the differentiation capability issue without requiring complex additional reagents or procedures.
Solution Approach 2:
The patent modifies the growth media by incorporating specific concentrations of crystal violet and other selective agents to create an environment that favors Mycobacterium growth while inhibiting other bacteria. By adjusting chemical parameters of the media composition, the patent achieves selective differentiation and enrichment of Mycobacterium from contaminated samples.
2Measurement precision
If harsh pretreatment reagents (CPC, NALC-NaOH) are used to isolate Mycobacterium from contaminated samples, then non-mycobacterial growth is inhibited, but the growth of multiple species of mycobacterium is significantly inhibited
Solution Approach 1:
The patent uses milder pretreatment reagents with optimized concentrations that selectively inhibit non-mycobacterial growth while preserving mycobacterium viability. By carefully adjusting the chemical parameters of the pretreatment solution, the patent achieves differentiation without the harsh effects of traditional reagents like CPC or NALC-NaOH.
Solution Approach 2:
The patent introduces a intermediate pretreatment step that selectively removes or inhibits competing bacteria before plating, using reagents that are less harsh than traditional options. This intermediary treatment protects mycobacterium from the full impact of strong antimicrobial agents while still achieving the desired isolation effect.
3Measurement precision
If complex pretreatment protocols (incubations and centrifugations) are used to pretreat samples, then non-mycobacterial contamination is reduced, but the procedure becomes time-consuming (over an hour per sample)
Solution Approach 1:
The patent extracts or removes the time-consuming steps of multiple incubations and centrifugations from the pretreatment protocol. By using a simplified single-step or reduced-step pretreatment method that achieves the same purification effect, the patent dramatically reduces the time required while maintaining sample purity and isolation quality.
4Reliability
If culture plates are used as the gold standard for identifying mycobacterial infections, then the method is reliable and widely accepted, but the detection process is lengthy and expensive
Solution Approach 1:
The patent uses crystal violet staining that provides immediate visual differentiation of Mycobacterium colonies, allowing for rapid identification without requiring lengthy incubation periods or complex diagnostic procedures. The color change occurs during or immediately after the plating process, dramatically reducing detection time while maintaining reliability.
Solution Approach 2:
The patent incorporates selective agents and staining components directly into the growth media before plating, so that the differentiation and selection process begins immediately upon inoculation. This preliminary preparation eliminates the need for subsequent time-consuming processing steps required by traditional culture methods.
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 MYChrOme medium and MYCOn pretreatment significantly improve the sensitivity and cost-effectiveness of Mycobacterium detection, demonstrating 62.8% greater sensitivity compared to standard methods, and effectively differentiate Mycobacterium from other bacteria, facilitating early detection and prevention of NTM infections.
Implementation Method 1
The growth medium may comprise an agar based growth medium comprising agar, one or more amino acid and nitrogenous supplementation elements, one or more trace elements and vitamins, one or more carbon sources, one or more neutralizing agents, and crystal violet. The crystal violet may be provided in an amount in excess of 0.5 μg/ml.
Implementation Method 2
A novel growth medium, MYChrOme, containing high concentrations of crystal violet and a pretreatment method, MYCOn, using sodium dodecyl sulfate and glycine hydrochloride, which selectively enhances the detection of Mycobacterium by inhibiting the growth of other bacteria
Data Source
AI summary
To determine the presence of Mycobacterium in an environment, a sample from the environment can be plated onto a growth medium that is selective for Mycobacterium. The agar based growth medium can include a high concentration of crystal violet, in excess of 0.5 μg/ml. The process may be made further selective for Mycobacterium by treating the sample with sodium dodecyl sulfate containing glycine hydrochloride for at least 4 minutes at room temperature, prior to plating. Mycobacterium colonies will generally appear white while other colonies will generally appear stained purple or another color.