Mycobacterium tuberculosis drug sensitivity testing method
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Solution Overview
Problem
Current methods for testing drug sensitivity of Mycobacterium tuberculosis are time-consuming, unsafe, and costly, with long test durations, complex operations, and high equipment and reagent costs, posing challenges in effectively managing drug-resistant tuberculosis.
Innovation Solution
A method utilizing a liquid medium for enriched culture, a temperature-adjustable solid medium, and a tellurite-based indicator for rapid drug sensitivity testing, which reduces test time, enhances safety, and lowers costs by optimizing bacterial growth and visualization of drug inhibition zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the prior paper strip test method or concentration test method is used for drug sensitivity testing of mycobacterium tuberculosis, then the test can determine drug sensitivity, but the test time is too long (about two months)
Solution Approach 1:
The patent applies preliminary action by pre-treating the specimen to obtain enriched specimens before the main drug sensitivity test. The enrichment step concentrates the mycobacterium tuberculosis bacteria, allowing the subsequent drug sensitivity test to proceed much faster (10 days vs. 2 months) because there are sufficient bacteria to work with from the start, eliminating the need for lengthy culture multiplication phases.
2Measurement precision
If the prior paper strip test method is used, then the equipment and reagent costs are high and operations are complex, but the method can determine drug sensitivity
Solution Approach 1:
The patent extracts and utilizes the biochemical reaction characteristics of mycobacterium tuberculosis directly in the enriched specimen without requiring complex paper strip systems or multiple test containers. By using the bacteria's inherent biochemical properties (oxidase enzyme activity) to produce visible color changes, the method eliminates complicated equipment and simplifies operations to basic microscopy and color observation.
3Measurement precision
If the prior paper strip test method or concentration test method is used, then the operation is unsafe due to artificial inoculation of infectious mycobacterium tuberculosis, but the test can determine drug sensitivity
Solution Approach 1:
The patent uses an intermediary approach by working with enriched specimens that have been processed to concentrate bacteria, rather than performing repeated artificial inoculations. The method observes biochemical reactions in the enriched specimen itself, eliminating the need for multiple inoculation steps and reducing operator exposure risk to infectious mycobacterium tuberculosis while maintaining detection accuracy.
4Measurement precision
If expensive equipment and reagents are used for drug sensitivity testing, then the test can be performed accurately, but the investment and use cost are high
Solution Approach 1:
The patent employs simple, inexpensive reagents and materials that can be easily prepared and disposed of. The method uses basic microscopy and color observation instead of expensive automated systems, and the reagents required are common laboratory chemicals rather than specialized expensive reagents. This dramatically reduces both initial investment and ongoing operational costs while maintaining accurate drug sensitivity detection.
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 significantly shortens the overall test time to 10 days, improves operational safety, and reduces costs by utilizing simpler, less expensive equipment and reagents, while effectively determining drug sensitivity.
Implementation Method 1
Adding a liquid medium to the enriched specimens to obtain liquid culture specimens, and performing enriched culture
Implementation Method 2
the solid medium having a melting temperature of 50-95°C and a solidification temperature of 25-45°C
Implementation Method 3
Dripping an indicator to the solid specimens when the sold specimens turn pink or light yellow in (6), observing a drug inhibition zone through a visible color change of the indicator
Data Source
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AI summary
A testing method for drug sensitivity of Mycobacterium tuberculosis, application of the indicator used in the method, solid medium and constant temperature heater and culture box used in the method are provided. The testing method for drug sensitivity of Mycobacterium tuberculosis comprises following steps: pretreating the provided specimen, and then adding liquid medium to conduct enrichment culturing, heating the solid medium to melt to prepare the solid medium in liquid state, mixing the specimen after enrichment culturing with the solid medium in liquid state, cooling to solid state, and preparing the solid drug sensitivity test specimen with drug sensitivity paper, culturing it for 5-15 days, observing the drug inhibiting ring by using an indicator to verify the drug sensitivity. The method costs less time for test and enables to perform drug sensitivity test of Mycobacterium tuberculosis in a safe and cost-effective manner.