Description:FIELD OF THE INVENTION

[0001] The present invention relates to a zone of inhibition analysis apparatus and method thereof for antibiotic susceptibility testing that is capable of improving the process of determining diameter of an inhibition zone by simplifying how results are observed and recorded, ensuring consistent evaluation, reducing the need for separate tools, and minimizing chances of human error in clinical, research, and educational environments.

BACKGROUND OF THE INVENTION

[0002] Antibiotic susceptibility testing (AST) is a crucial process in microbiology and clinical diagnostics, used to determine the effectiveness of antibiotics against specific bacterial strains. One of the most commonly used methods for AST is the disk diffusion method, which involves placing an antibiotic-impregnated disk on an agar plate inoculated with bacteria. After incubation, a clear circular area, known as the zone of inhibition, appears around the disk where bacterial growth is prevented. Measuring the diameter of this zone helps evaluate the bacteria’s resistance or sensitivity to the antibiotic. Accurate measurement of the zone is essential for determining appropriate treatment options, preventing antibiotic misuse, and monitoring resistance patterns in clinical and research settings.

[0003] Traditionally, the zone of inhibition is measured using a simple ruler or caliper after visual observation of the plate. In some cases, templates or transparent grids are used to estimate the diameter. These methods often rely on manual alignment and estimation, which may lead to inconsistencies in results due to parallax error, human error, or lack of standardized measurement technique. Additionally, interpreting irregularly shaped zones are challenging without defined reference points, affecting accuracy and repeatability in clinical or research reports. Some advanced laboratories use digital imaging systems or software for zone measurement, but these are expensive, require maintenance, and are not accessible in resource-limited settings. The use of non-sterile or reusable tools also poses a risk of contamination and error between samples.

[0004] US4221867A discloses a device for determining the susceptability of microorganisms, i.e., bacteria, to antibiotics is provided. The device utilizes a layer of light transmissive material having a plurality of flat, opaque louver elements set in a transparent matrix which permit transmission of visible light and illumination of a sample being tested. A method for determining the susceptability is also provided.

[0005] US20230340560A1 discloses an antibiotic susceptibility evaluation apparatus including a sample unit including a sample and at least an antibiotic disk arranged on the sample, a light source radiating coherent light to the sample unit, an image sensor detecting transmitted light passing through the sample unit to obtain a sample image, and a controller configured to receive a first sample image, which is an image of the sample at an initial time when the antibiotic disk is arranged on the sample unit, and a second sample image, which is an image of the sample after a preset time, to obtain a spatial correlation of an interference pattern between the first sample image and the second sample image, and to evaluate susceptibility of the sample to antibiotics based on the spatial correlation according a position.

[0006] Conventionally, many devices and apparatus such as antibiotic disk have been developed in order to measure the zone of inhibition for antibiotic susceptibility testing more accurately and efficiently, however, the devices and apparatus mentioned in the prior arts have limitations pertaining to high cost, complexity, dependency on advanced imaging technology, and requiring specialized training for operation and maintenance, making them less practical for routine use in many laboratories and clinics.

[0007] In order to overcome the aforementioned drawbacks, there exists a need in the art to develop an apparatus that requires to be simple, cost-effective, and easy to use for accurate measurement of the zone of inhibition, allowing direct and immediate reading of results without requiring complex equipment.

OBJECTS OF THE INVENTION

[0008] The principal object of the present invention is to overcome the disadvantages of the prior art.

[0009] An object of the present invention is to develop an apparatus that enables quick and accurate measurement of antibiotic effectiveness by integrating the measurement scale directly with the antibiotic disk, reducing the need for extra tools and speeding up testing.

[0010] Another object of the present invention is to develop an apparatus that simplifies antibiotic susceptibility testing by combining measurement and antibiotic delivery, ensuring faster, more accurate results while minimizing errors and equipment requirements.

[0011] Another object of the present invention is to develop an apparatus that is capable of providing consistent and repeatable results for determination of the effectiveness of antibiotics on bacterial cultures.

[0012] Yet another object of the present invention is to develop an apparatus that is capable of reducing manual errors and eliminating subjectivity by offering a simple and fixed reference for measuring inhibition zones.

[0013] The foregoing and other objects, features, and advantages of the present invention will become readily apparent upon further review of the following detailed description of the preferred embodiment as illustrated in the accompanying drawings.

SUMMARY OF THE INVENTION

[0014] The present invention relates to a zone of inhibition analysis apparatus and method thereof for antibiotic susceptibility testing that is capable of helping in antimicrobial susceptibility by combining observation and measurement functions into a single setup, thereby enhancing accuracy, reducing procedural steps, and making the process more reliable.

[0015] According to an embodiment of the present invention, a zone of inhibition analysis apparatus for antibiotic susceptibility testing is disclosed comprising: i) a support platform, ii) an antibiotic disk mounted on the support platform and to be placed on an agar plate pre-inoculated with a bacterial lawn, and iii) horizontal and vertical rulers each having gradual markings, intersecting at center of the disk for measurement of zone of inhibition, the disk is having concentric rings of fixed diameters for increasing accuracy in measuring the zone of inhibition, the fixed diameters includes, but not limited to 6 mm, 12 mm, 18 mm, the support platform is made from material which includes, but not limited to paper, plastic, or transparent sheet, the apparatus is sterilizable and for single use.

[0016] According to another embodiment of the present invention, a method for measuring zone of inhibition using the zone of inhibition analysis apparatus claimed in claim 1, comprising the steps: a) Impregnating the apparatus with antibiotic and placing the apparatus on an agar plate pre-inoculated with a bacterial lawn, as per standard antimicrobial susceptibility testing (AST) protocols, b) incubating the plate at appropriate temperature for optimal time duration, c) observing the clear zone of inhibition around the disk, d) recording the zone of inhibition by aligning the edges of the clear zone of inhibition with the markings on the horizontal and vertical rulers, and the incubation temperature and time duration depends on the bacterial lawn grown on the agar plate.

[0017] While the invention has been described and shown with particular reference to the preferred embodiment, it will be apparent that variations might be possible that would fall within the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
Figure 1 illustrates a front view of horizontal and vertical rulers of a zone of inhibition analysis apparatus;
Figure 2 illustrates a pictorial representation of a back view of horizontal and vertical rulers of the apparatus; and
Figure 3 illustrates a pictorial representation of predefined diameter printed around the antibiotic disk.

DETAILED DESCRIPTION OF THE INVENTION

[0019] The following description includes the preferred best mode of one embodiment of the present invention. It will be clear from this description of the invention that the invention is not limited to these illustrated embodiments but that the invention also includes a variety of modifications and embodiments thereto. Therefore, the present description should be seen as illustrative and not limiting. While the invention is susceptible to various modifications and alternative constructions, it should be understood, that there is no intention to limit the invention to the specific form disclosed, but, on the contrary, the invention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the claims.

[0020] In any embodiment described herein, the open-ended terms "comprising," "comprises,” and the like (which are synonymous with "including," "having” and "characterized by") may be replaced by the respective partially closed phrases "consisting essentially of," consists essentially of," and the like or the respective closed phrases "consisting of," "consists of, the like.

[0021] As used herein, the singular forms “a,” “an,” and “the” designate both the singular and the plural, unless expressly stated to designate the singular only.

[0022] The present invention relates to a zone of inhibition analysis apparatus and method thereof for antibiotic susceptibility testing that provides integration of two straight rulers, one horizontal and one vertical that pass directly through center of an antibiotic disk to evaluate diameter of the zone of inhibition without the need for external tools.

[0023] According to an embodiment of the present invention, a zone of inhibition analysis apparatus for antibiotic susceptibility testing is disclosed comprising: i) a support platform, ii) an antibiotic disk mounted on the support platform and to be placed on an agar plate pre-inoculated with a bacterial lawn, and iii) horizontal and vertical rulers each having gradual markings, intersecting at center of the disk for measurement of zone of inhibition. Figure 1 and 2 illustrates a front view of horizontal and vertical rulers of a zone of inhibition analysis apparatus and a pictorial representation of a back view of horizontal and vertical rulers of the apparatus.

[0024] The disk is having concentric rings of fixed diameters for increasing accuracy in measuring the zone of inhibition.

[0025] The fixed diameters include, but not limited to 6 mm, 12 mm, 18 mm.

[0026] The support platform of the apparatus may be constructed using materials such as paper, plastic, or a transparent sheet, depending on the intended use. The apparatus is designed to be sterilisable and is preferably configured for single use, minimizing the risk of cross-contamination and ensuring hygiene in microbiological testing.

[0027] According to another embodiment of the present invention, a method for measuring zone of inhibition using the zone of inhibition analysis apparatus comprises of the following steps: a) Impregnating the apparatus with antibiotic and placing the apparatus on an agar plate pre-inoculated with a bacterial lawn, as per standard AST protocols, b) incubating the plate at appropriate temperature for optimal time duration, c) observing the clear zone of inhibition around the disk, and d) recording the zone of inhibition by aligning the edges of the clear zone of inhibition with the markings on the horizontal and vertical rulers.

[0028] The incubation temperature and time duration depends on the bacterial lawn grown on the agar plate.

EXAMPLE

[0029] The method for measuring zone of inhibition using the zone of inhibition analysis apparatus includes of the following steps:

[0030] Preparation: Begin by placing the antibiotic disk, which is integrated with horizontal and vertical measurement rulers, onto an agar plate that has been pre-inoculated with a uniform bacterial lawn. This step follows standard antibiotic susceptibility testing (AST) protocols, where the bacterial inoculum is evenly spread to ensure consistent growth across the plate. The disk should be positioned centrally on the agar surface to allow uniform diffusion of the antibiotic in all directions during incubation.

[0031] Incubation: Once the disk is placed, incubate the agar plate at a temperature and for a duration appropriate for the specific bacterial strain used. These parameters typically depend on the growth requirements of the organism and are consistent with clinical and microbiological guidelines. Proper incubation allows the antibiotic to diffuse radially from the disk into the surrounding medium, inhibiting bacterial growth in a circular pattern if the bacteria are susceptible.

[0032] Measurement: Following the incubation period, observe the clear circular region around the antibiotic disk, known as the zone of inhibition, which indicates the extent of bacterial growth suppression. Use the built-in horizontal and vertical rulers integrated into or surrounding the disk to measure the diameter of this zone directly. This eliminates the need for external tools such as calipers or separate measuring scales and reduces the possibility of measurement errors due to manual misalignment.

[0033] Recording and Interpretation: Referring to Figure 1, a front view of horizontal and vertical rulers of a zone of inhibition analysis apparatus is illustrated. Referring to Figure 2, a pictorial representation of a back view of horizontal and vertical rulers of the apparatus is illustrated. Referring to Figure 3, a pictorial representation of predefined diameter printed around the antibiotic disk is illustrated.

[0034] Once the measurement is taken, record the diameter of the zone of inhibition by aligning the edges of the clear zone with the corresponding gradations on the horizontal and vertical rulers. This allows for precise, quick, and repeatable documentation of results. The recorded measurements are then compared with standardized AST interpretation charts to determine the susceptibility or resistance of the tested bacteria to the antibiotic used.

[0035] The present invention may be embodied in several different variants to accommodate diverse applications, user requirements, and environmental conditions. These variants are broadly categorized based on material composition, scale design, and application scope.

[0036] In an embodiment of the present invention, the apparatus is provided in two material variants, disposable and reusable. In the disposable apparatus, the apparatus is made from sterilizable paper or lightweight polymer materials, intended for single use to maintain sterility and avoid cross-contamination between tests. In the reusable apparatus, the base of the apparatus is constructed from durable plastic or polycarbonate material, allowing for repeated usage. This version may include replaceable antibiotic disks, enabling continued use of the ruler base while ensuring testing accuracy and integrity.

[0037] In another embodiment of the present invention, the apparatus includes different scale design variants to accommodate measurement preferences and enhance accuracy. One such design variant of the apparatus incorporates horizontal and vertical linear rulers with gradual markings intersecting at the center of the disk, allowing direct and precise diameter readings. Another design variant features concentric circular rings with predefined diameters, including but not limited to 6 mm, 12 mm, and 18 mm, allowing users to match and evaluate the size of the inhibition zone visually without relying on manual measurement tools.

[0038] In yet another embodiment of the present invention, the apparatus is adapted for a variety of applications beyond clinical microbiology. These applications include veterinary microbiology for testing antimicrobial resistance in animal pathogens, food safety testing for detecting resistant bacteria in consumables, and water quality monitoring for assessing microbial contamination. Additionally, the apparatus may be integrated into educational kits for microbiology students, providing a simple, low-cost tool for laboratory training and practical demonstrations.

[0039] The invention offers several advantages that enhance efficiency and efficacy. Its integrated measurement means eliminates the need for separate rulers or callipers, enabling faster and more accurate readings of the zone of inhibition. This reduces manual errors and misalignment during measurement, thereby improving the reliability of antimicrobial susceptibility results. The design speeds up the diagnostic workflow in laboratories and clinical settings by allowing direct readings from the disk setup, saving valuable time. Additionally, the user-friendly design simplifies operation and reduces the need for extensive training, making it especially useful in educational institutions and resource-limited environments. Its portability makes it ideal for field laboratories and mobile health units where traditional measuring tools may not be available. Furthermore, the invention promotes standardized measurement protocols across technicians and laboratories, enhancing data quality and comparability.

[0040] Although the field of the invention has been described herein with limited reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. , Claims:1) A zone of inhibition analysis apparatus for antibiotic susceptibility testing, comprising:
i) a support platform
ii) an antibiotic disk mounted on the support platform and to be placed on an agar plate pre-inoculated with a bacterial lawn; and
iii) horizontal and vertical rulers each having gradual markings, intersecting at center of the disk for measurement of zone of inhibition.

2) The apparatus as claimed in claim 1, wherein the disk is having concentric rings of fixed diameters for increasing accuracy in measuring the zone of inhibition.

3) The apparatus as claimed in claim 2, wherein the fixed diameters includes, but not limited to 6 mm, 12 mm, 18 mm.

4) The apparatus as claimed in claim 1, wherein the support platform is made from material which includes, but not limited to paper, plastic, or transparent sheet.

5) The apparatus as claimed in claim 1, wherein the apparatus is sterilizable and for single use.

6) A method for measuring zone of inhibition using the zone of inhibition analysis apparatus claimed in claim 1, comprising the steps:
a) Impregnating the apparatus with antibiotic and placing the apparatus on an agar plate pre-inoculated with a bacterial lawn, as per standard AST protocols;
b) incubating the plate at appropriate temperature for optimal time duration;
c) observing the clear zone of inhibition around the disk; and
d) recording the zone of inhibition by aligning the edges of the clear zone of inhibition with the markings on the horizontal and vertical rulers.

7) The method as claimed in claim 6, wherein the incubation temperature and time duration depends on the bacterial lawn grown on the agar plate.