Antimicrobial Sensitivity Assessment Using Solid Nutrient Media

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Solution Overview

Problem

Current methods for determining the sensitivity of microorganisms to antimicrobial substances are inefficient due to the need for isolating pure cultures, which is time-consuming and often impossible for 'not-yet-cultivated' microbes, leading to low precision and the emergence of resistant forms, especially in the presence of microbial communities like biofilms.

Innovation Solution

A method using a solid, rich nutrient medium to cultivate all microorganisms from biological material with the antimicrobial substance introduced at a concentration similar to its maximum achievable concentration, allowing for the assessment of sensitivity based on visible growth in a control culture without the need for isolating specific microorganisms, promoting growth with added microorganisms and varying conditions like oxygen levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If preliminary isolation of pure culture is performed to determine sensitivity, then identification accuracy is improved, but time consumption increases significantly (48-96 hours)

Engineering Contradiction:
Improveidentification accuracyVSAvoidtime consumption
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by adding the antimicrobial substance to the nutrient medium before inoculating the microorganism. This allows the sensitivity determination to proceed simultaneously with culture growth, eliminating the need for separate identification steps and reducing total time from 48-96 hours to 4-6 hours while maintaining accuracy through direct observation of growth inhibition.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If pure culture isolation is performed, then sensitivity determination precision is improved, but the method becomes inapplicable to uncultivated microbes (90-95% of microbes)

Engineering Contradiction:
Improvesensitivity determination precisionVSAvoidapplicability to uncultivated microbes
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal method that works for both cultivated and uncultivated microbes by using a solid nutrient medium that supports growth of diverse microorganisms without requiring pure culture isolation. The method directly tests sensitivity on mixed cultures or uncultivated microbes, making it applicable to 90-95% of microbes that were previously inaccessible.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If broad-spectrum antibiotics are used empirically, then treatment coverage is improved, but resistance formation accelerates

Engineering Contradiction:
Improvetreatment coverageVSAvoidresistance formation
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements feedback by providing rapid sensitivity determination (4-6 hours) that enables clinicians to adjust treatment based on actual microbial response. This allows switching from empirical broad-spectrum antibiotic use to targeted therapy based on observed sensitivity, thereby reducing resistance formation while maintaining effective treatment coverage.

Inventive Principle:
Principle #23Feedback

4Measurement precision

If serial dilution method with pure culture is used, then sensitivity assessment is improved, but the complexity of the procedure increases

Engineering Contradiction:
Improvesensitivity assessment precisionVSAvoidprocedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the essential function of sensitivity determination from the complex serial dilution procedure by directly adding a single concentration of antimicrobial substance to the solid nutrient medium before inoculation. This eliminates the need for multiple dilution steps and complex equipment, simplifying the procedure while maintaining assessment precision through direct growth observation.

Inventive Principle:
Principle #2Taking out (Extraction)

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 significantly increases the precision of determining antimicrobial sensitivity, enabling quick identification of effective substances within hours, even for uncultivated microbes, without altering the microbial composition and addressing resistance issues.

Implementation Method 1

a solid, rich nutrient medium is used for cultivating the microorganisms

Methodology Applied
Scientific EffectMicrobial growth: Fermentation

Implementation Method 2

introducing an antimicrobial substance to be investigated into the nutrient medium

Methodology Applied
Scientific EffectAntimicrobial action:

Implementation Method 3

the sensitivity of the microorganisms to the antimicrobial substance is assessed after the appearance of visible growth of microorganisms in a control culture

Methodology Applied
Scientific EffectMicrobial proliferation: Fermentation

Data Source

PatentEP2918672B1Method for determining the sensitivity of microorganisms to antimicrobial substances
Publication Date: 2019.05.08 TETS

AI summary

The invention relates to medicine and to veterinary medicine, and specifically to means for determining the sensitivity of various microorganisms, including bacteria and fungi, to antimicrobial substances. The method for determining the sensitivity of microorganisms to antimicrobial substances comprises taking biological material, incubating microorganisms contained therein on a nutrient medium, introducing an antimicrobial substance to be investigated into the nutrient medium and subsequently assessing the result. A dense, rich nutrient medium is used for cultivating the microorganisms. The antimicrobial substance being investigated is introduced into the nutrient medium prior to cultivation of the microorganisms in a concentration close to the maximum concentration achievable at the location at which the biological material is taken. The sensitivity of the microorganisms to the antimicrobial substance is assessed after the appearance of visible growth of microorganisms in a control culture. Vitamins and/or amino acids, and/or nutritional supplements can be added to the nutrient medium.