Sensitive and rapid determination of antimicrobial susceptibility
Inventors
Goldberg, David A. • Howson, David C. • Metzger, Steven W. • Buttry, Daniel A. • Saavedra, Steven Scott
Assignees
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Publication Number
US-11054420-B2
Publication Date
2021-07-06
Expiration Date
Abstract
The present invention relates to moving microorganisms to a surface, where they are grown in the presence and absence of antimicrobials, and by monitoring the growth of the microorganisms over time in the two conditions, their susceptibility to the antimicrobials can be determined. The microorganisms can be moved to the surface through electrophoresis, centrifugation or filtration. When the movement involves electrophoresis, the presence of oxidizing and reducing reagents lowers the voltage at which electrophoretic force can be generated and allows a broader range of means by which the target can be detected. Monitoring can comprise optical detection, and most conveniently includes the detection of individual microorganisms. The microorganisms can be stained in order to give information about their response to antimicrobials.
Core Innovation
The invention provides a method of detecting growth of a microorganism in a sample by contacting the sample with a device that includes a chamber and a detection zone, wherein the detection zone comprises a hydrogel. The microorganism is immobilized by capture with the hydrogel, and an electrophoretic force is applied to the microorganism within the chamber for analysis.
An optical detector detects a property of the microorganism at a first time and again at a second time, and the amount of difference of the property between the first time and the second time is determined. Growth is detected from optical changes across time while the microorganism remains immobilized in the hydrogel detection zone under electrophoretic force.
The document further describes continuous or interval application of the electrophoretic force, additional differences determined at later time points, and optical detection modes including evanescent illumination or waveguides and surface plasmon resonance.
Claims Coverage
The consolidated claim coverage includes one independent claim centered on a time-difference optical method for detecting microorganism growth using a hydrogel immobilized detection zone with electrophoretic force, with optical measurements at first and second times and determination of the amount of difference. Dependent refinements further specify electrophoretic force application, sample composition, and additional time-point comparisons.
Hydrogel immobilized detection zone with chamber and optical detector
Contacting a sample comprising a microorganism with a device comprising a chamber, wherein the chamber comprises a detection zone, and wherein the detection zone comprises a hydrogel; immobilizing the microorganism by capture with the hydrogel; and detecting, at a first time, a property of the microorganism with an optical detector and detecting, at a second time, the property of the microorganism with the optical detector.
Electrophoretic force and time-point property difference determination
Applying an electrophoretic force to the microorganism; and determining the amount of difference of the property of the microorganism between the first time and the second time.
The inventive coverage centers on immobilizing microorganisms in a hydrogel detection zone, applying an electrophoretic force, measuring a microorganism property optically at two time points, and determining the amount of difference between the first and second optical measurements.
Stated Advantages
Determines growth of a microorganism by quantifying an amount of difference of an optical property between a first time and a second time.
Enables viability determination using growth and vital/mortal stains.
Assesses susceptibility by determining MIC and MBC using antibiotics or an anti-organism agent.
Enables a rapid antimicrobial susceptibility approach by monitoring optical growth/no-growth conditions over time.
Documented Applications
Detecting growth of a microorganism in a sample by immobilizing the microorganism with a hydrogel in a chamber detection zone and performing optical property measurements at first and second times.
Determining viability of immobilized bacteria using growth and vital/mortal stains.
Assessing antibiotic or anti-organism agent susceptibility by incubating with antibiotics or agents at increasing concentrations to determine MIC and MBC.
Organism detection workflows that concentrate samples and transport to detection zones, followed by immobilizing microorganisms on capture surfaces and longitudinal optical monitoring with image registration or detector feedback.
Detecting growth of a microorganism in a sample for antimicrobial susceptibility monitoring using optical properties under growth/no-growth conditions.
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