HardyDisk AST disks are used for semi-quantitative in vitro susceptibility testing by the agar diffusion test procedure (Kirby-Bauer) of rapidly growing and certain fastidious bacterial pathogens. Standardized methods for agar diffusion testing have been described for Enterobacterales, Staphylococcus spp., Pseudomonas spp., Acinetobacter spp., Listeria monocytogenes, Enterococcus spp., and by modified procedures, Candida spp., Haemophilus spp., Neisseria gonorrhoeae, Neisseria meningitidis and Streptococcus spp., including Streptococcus pneumoniae. Use of HardyDisk AST Tebipenem 10μg (TBP10) for in vitro agar diffusion susceptibility testing is indicated when there is the need to determine the susceptibility of Enterobacterales to tebipenem, as recognized by the FDA Susceptibility Test Interpretive Criteria (STIC). HardyDisk AST Tebipenem at concentration 10μg demonstrated acceptable performance to determine the zone diameter (mm) of tebipenem against the following microorganisms: Enterobacterales (Escherichia coli, Enterobacter cloacae species complex, Klebsiella oxytoca, Klebsiella pneumoniae, Citrobacter freundii complex, Citrobacter koseri, Klebsiella aerogenes, Morganella morganii, Proteus mirabilis, Providencia rettgeri, Klebsiella variicola, Serratia marcescens)
Device Story
HardyDisk AST Tebipenem 10μg consists of 6 mm filter paper disks impregnated with 10μg tebipenem; used in clinical microbiology laboratories for Kirby-Bauer agar diffusion susceptibility testing. Procedure involves inoculating Mueller Hinton agar with bacterial suspension (0.5 McFarland standard); placing disks onto agar surface; incubating at 35±2°C for 16-18 hours. Healthcare providers measure zone of inhibition diameters (mm) and compare against FDA-recognized STIC breakpoints to categorize organisms as Susceptible, Intermediate, or Resistant. Results inform antimicrobial therapy selection for patients with bacterial infections. Includes a Pre-Determined Change Control Plan (PCCP) for updating labeling based on future FDA STIC breakpoint revisions.
Clinical Evidence
No clinical trials performed. Evidence based on right of reference to NDA 215960 and CDER-evaluated microbiology disk studies. Performance characteristics (stability, quality control, disk-to-MIC correlation, and reproducibility) were generated in accordance with CDER guidance for antimicrobial drugs. CDER concurred with CLSI-established disk QC ranges.
Technological Characteristics
Antimicrobial susceptibility test disk; 10μg tebipenem concentration; paper disk form factor; Kirby-Bauer agar diffusion principle; in vitro diagnostic use.
Indications for Use
Indicated for in vitro semi-quantitative susceptibility testing of Enterobacterales (including E. coli, K. pneumoniae, P. mirabilis, etc.) to tebipenem using the Kirby-Bauer agar diffusion method. For prescription use only.
Regulatory Classification
Identification
An antimicrobial susceptibility test disc is a device that consists of antimicrobic-impregnated paper discs used to measure by a disc-agar diffusion technique or a disc-broth elution technique the in vitro susceptibility of most clinically important bacterial pathogens to antimicrobial agents. In the disc-agar diffusion technique, bacterial susceptibility is ascertained by directly measuring the magnitude of a zone of bacterial inhibition around the disc on an agar surface. The disc-broth elution technique is associated with an automated rapid susceptibility test system and employs a fluid medium in which susceptibility is ascertained by photometrically measuring changes in bacterial growth resulting when antimicrobial material is eluted from the disc into the fluid medium. Test results are used to determine the antimicrobial agent of choice in the treatment of bacterial diseases.
Submission Summary (Full Text)
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[LOGO]
FDA
U.S. FOOD & DRUG
ADMINISTRATION
### 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION
DECISION SUMMARY
ASSAY ONLY
### I Background Information:
A 510(k) Number
K262113
B Applicant
Hardy Diagnostics
C Proprietary and Established Names
HardyDisk AST Tebipenem 10μg (TBP10)
D Regulatory Information
| Product Code(s) | Classification | Regulation Section | Panel |
| --- | --- | --- | --- |
| JTN | Class II | 21 CFR 866.1620 - Antimicrobial Susceptibility Test Disc | MI - Microbiology |
### II Submission/Device Overview:
A Purpose for Submission:
In this Traditional 510(k) submission, Hardy Diagnostics seeks the following:
1. To obtain a substantial equivalence determination for the tebipenem antimicrobial susceptibility test disk for testing with Enterobacterales
2. To establish a Pre-Determined Change Control Plan (PCCP) to address future revisions to device labeling in response to breakpoint changes that are recognized on the FDA STIC webpage.
B Measurand:
Tebipenem 10μg
C Type of Test:
Antimicrobial Susceptibility Test Disks
Food and Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993-0002
www.fda.gov
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### III Intended Use/Indications for Use:
#### A Intended Use(s):
See Indications for Use below.
#### B Indication(s) for Use:
HardyDisk AST disks are used for semi-quantitative *in vitro* susceptibility testing by the agar diffusion test procedure (Kirby-Bauer) of rapidly growing and certain fastidious bacterial pathogens. Standardized methods for agar diffusion testing have been described for Enterobacterales, *Staphylococcus* spp., *Pseudomonas* spp., *Acinetobacter* spp., *Listeria monocytogenes*, *Enterococcus* spp., and by modified procedures, *Candida* spp., *Haemophilus* spp., *Neisseria gonorrhoeae*, *Neisseria meningitidis* and *Streptococcus* spp., including *Streptococcus pneumoniae*.
Use of HardyDisk AST Tebipenem 10μg (TBP10) for *in vitro* agar diffusion susceptibility testing is indicated when there is the need to determine the susceptibility of Enterobacterales to tebipenem, as recognized by the FDA Susceptibility Test Interpretive Criteria (STIC).
HardyDisk AST Tebipenem at concentration 10μg demonstrated acceptable performance to determine the zone diameter (mm) of tebipenem against the following microorganisms:
Enterobacterales (*Escherichia coli*, *Enterobacter cloacae* species complex, *Klebsiella oxytoca*, *Klebsiella pneumoniae*, *Citrobacter freundii* complex, *Citrobacter koseri*, *Klebsiella aerogenes*, *Morganella morganii*, *Proteus mirabilis*, *Providencia rettgeri*, *Klebsiella variicola*, *Serratia marcescens*)
#### C Special Conditions for Use Statement(s):
Rx - For Prescription Use Only
#### D Special Instrument Requirements:
Not applicable.
### IV Device/System Characteristics:
#### A Device Description:
HardyDisk AST Tebipenem 10μg (TBP10) is a high quality 6 mm diameter white filter paper disk that is impregnated with 10μg tebipenem. The disks are clearly marked on both sides with TBP10, designating the agent and the drug concentration. The disks are supplied in plastic cartridges containing 50 disks each. HardyDisk AST Tebipenem 10μg (TBP10) is intended to be used for *in vitro* agar diffusion susceptibility testing.
#### B Principle of Operation:
The HardyDisk AST Disk is based on the agar diffusion (Kirby-Bauer) methodology. It utilizes dried filter paper disks impregnated with a known concentration of an antimicrobial agent that are placed onto the test medium surface. Three to five similar colonies are transferred to 4-5 mL of a suitable broth medium. The broth is incubated at 35°C for 2-6 hours to develop a turbidity
K262113 - Page 2 of 7
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that exceeds or is equivalent to a 0.5 McFarland standard. Alternatively, a direct broth or saline suspension of colonies may be prepared from an overnight culture. The final inoculum density should be equivalent to a 0.5 McFarland turbidity standard. The inoculum density may also be standardized photometrically.
Within 15 minutes of inoculum preparation, the Mueller Hinton agar plate is streaked with an inoculated swab to obtain an even inoculation of organism. Disks are aseptically placed onto the agar surface with a disk dispenser, and the disks are pressed down with a sterile needle or forceps to contact the agar surface. Agar plates are incubated in an ambient air incubator at 35±2°C for 16-18 hours.
After incubation, the agar medium is examined for a zone of inhibition around the disks. The zones of inhibition are measured to the nearest millimeter and interpreted by comparison to recognized zone size interpretive criteria for the antimicrobial agent being tested.
# V Substantial Equivalence Information:
# A Predicate Device Name(s):
HardyDisk AST Gepotidacin 10μg (GEP10)
# B Predicate 510(k) Number(s):
K260842
# C Comparison with Predicate(s):
| Device & Predicate Device(s): | Device K262113 | Predicate K260842 |
| --- | --- | --- |
| Device Trade Name | HardyDisk AST Tebipenem 10μg (TBP10) | HardyDisk AST Gepotidacin 10μg (GEP10) |
| **General Device Characteristic Similarities** | | |
| Intended Use | Semi-quantitative *in vitro* susceptibility testing by the agar diffusion test procedure (Kirby-Bauer) of rapidly growing and certain fastidious bacterial pathogens. | Same |
| Test Method | Antimicrobial susceptibility testing using paper disks impregnated with an antimicrobial agent | Same |
| Methodology | Kirby-Bauer Disk Diffusion Susceptibility Test Protocol requires the user to determine categorical interpretations (S/I/R) using the measured zone diameters. | Same |
K262113 - Page 3 of 7
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| Device & Predicate Device(s): | Device K262113 | Predicate K260842 |
| --- | --- | --- |
| Inoculum | Prepared from pure isolated colonies to match the turbidity equivalent of a 0.5 McFarland in Tryptic Soy Broth. | Same |
| Inoculation Method | Dip a sterile swab into the prepared inoculum and streak an appropriate agar plate's surface three times. Add the disks impregnated with the antimicrobial agent to the surface of the plate. The temperature, atmospheric conditions and duration of incubation is dependent on the organism tested. | Same |
| Reading Method | The user will interpret the zone diameters according to the established interpretive criteria for the drug. | Same |
| Concentration | 10μg | Same |
| **General Device Characteristic Differences** | | |
| Test Organisms | Enterobacterales (*Escherichia coli, Enterobacter cloacae* species complex, *Klebsiella oxytoca, Klebsiella pneumoniae, Citrobacter freundii* complex, *Citrobacter koseri, Klebsiella aerogenes, Morganella morganii, Proteus mirabilis, Providencia rettgeri, Klebsiella variicola, Serratia marcescens*) | Enterobacterales (*Citrobacter freundii* complex, *Escherichia coli, Klebsiella pneumoniae, Citrobacter koseri, Klebsiella aerogenes, Klebsiella oxytoca/Raoultella ornithinolytica, Morganella morganii, Proteus mirabilis, Providencia rettgeri*) *Enterococcus faecalis* *Staphylococcus saprophyticus* *Neisseria gonorrhoeae* |
| Antimicrobial Agent | Tebipenem | Gepotidacin |
### Predetermined Change Control Plan (PCCP):
To support the implementation of changes to FDA-recognized susceptibility test interpretive criteria (i.e., breakpoints), this submission included a predetermined change control plan (PCCP) that was reviewed and accepted by FDA. This PCCP addresses future revisions to device labeling in response to breakpoint changes that are recognized on the FDA STIC webpage (FDA-
K262113 - Page 4 of 7
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Recognized Antimicrobial Susceptibility Test Interpretive Criteria). The PCCP outlined the specific procedures and acceptance criteria that Hardy Diagnostics intends to use to evaluate the HardyDisk AST Tebipenem 10μg (TBP10) when revised breakpoints for tebipenem are published on the FDA STIC webpage. The PCCP included with the submission indicated that if specific criteria are met, Hardy Diagnostics will update the HardyDisk AST Tebipenem 10μg (TBP10) device label to include the new breakpoints.
# VI Standards/Guidance Documents Referenced:
- CLSI M02-14th ed. Performance Standards for Antimicrobial Disk Susceptibility Tests (March 2024).
- CLSI M100-36th ed. Performance Standards for Antimicrobial Susceptibility Testing (January 2026).
# VII Performance Characteristics (if/when applicable):
The premarket submission for HardyDisk AST Tebipenem 10μg (TBP10) included a letter dated May 6, 2026, indicating the right of reference to NDA 215960. Descriptive characteristics regarding Enterobacterales testing were sufficient for the HardyDisk AST Tebipenem 10μg (TBP10) disk based on data from microbiology disk studies evaluated by CDER which were used to generate the breakpoints identified by FDA on the susceptibility test interpretive criteria (STIC) webpage. In addition, CDER concurred with the disk QC ranges that were established by CLSI. The disk data used to support this submission included data from testing organisms shown to be active in vitro and/or in clinical infections within the spectrum of activity of tebipenem.
Data obtained from stability, quality control, disk to MIC correlation, and reproducibility (from disk content optimization) studies were generated in accordance with the CDER Clinical/Antimicrobial guidance, Microbiology Data for Systemic Antibacterial Drugs-Development, Analysis, and Presentation to ensure precise, accurate, and reproducible results.
For this review, the interpretive criteria are applied to Enterobacterales according to the FDA STIC website. As required under 511A(2)(2)(B) of the Federal Food, Drug and Cosmetic Act, the following statement is included in the Precautions section of the HardyDisk AST Tebipenem 10μg (TBP10) package insert:
Per the FDA-Recognized Susceptibility Test Interpretive Criteria website, the safety and efficacy of antimicrobial drugs, for which antimicrobial susceptibility is tested by this AST device, may or may not have been established in adequate and well-controlled clinical trials for treating clinical infections due to microorganisms outside of those found in the indications and usage in the drug label. The clinical significance of susceptibility information in those instances is unknown. The approved labeling for specific antimicrobial drugs provides the uses for which the antimicrobial drug is approved.
# A Analytical Performance:
# 1. Precision/Reproducibility:
Not applicable.
K262113 - Page 5 of 7
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2. Linearity:
Not applicable.
3. Analytical Specificity/Interference:
Not applicable.
4. Detection Limit and Assay Reportable Range:
Not applicable.
5. Traceability, Stability, Expected Values (Controls, Calibrators, or Methods):
Not applicable.
6. Assay Cut-Off:
Not applicable.
# **B Comparison Studies:**
1. Method Comparison with Predicate Device:
Not applicable.
2. Matrix Comparison:
Not applicable.
# **C Clinical Studies:**
1. Clinical Sensitivity:
Not applicable.
2. Clinical Specificity:
Not applicable.
3. Clinical Cut-Off:
Not applicable.
4. Other Clinical Supportive Data (When 1. and 2. Are Not Applicable):
Not applicable.
# **D Expected Values/Reference Range:**
Not applicable.
# **E Expected Values/Reference Range:**
K262113 - Page 6 of 7
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The FDA-recognized susceptibility interpretive criteria for tebipenem are listed below in Table 1.
Table 1. FDA-Recognized Disk Diffusion Interpretive Criteria (zone diameter in mm) for Tebipenem
| Organisms | Interpretive Criteria (mm)^{a} | | |
| --- | --- | --- | --- |
| | Susceptible (S) | Intermediate (I) | Resistant (R) |
| Enterobacterales | ≥ 29 | 24 – 28 | ≤ 23 |
$^{a}$ FDA STIC Webpage, FDA-Recognized Antimicrobial Susceptibility Test Interpretive Criteria
### VIII Proposed Labeling:
The labeling supports the finding of substantial equivalence for this device.
### IX Conclusion:
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.
K262113 - Page 7 of 7
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Part 1 — Search, results, and everyday workflows 16 min
Part 2 — Embeddings: the galaxy map 3 min
1. Search: exact and fuzzy
Type a phrase like "coronary artery calcification" into the search box. You get two kinds of results. Exact results match the literal phrase — prefix searches work ("coronary artery calcificati") but suffix searches do not. Fuzzy results match on the meaning and intent of your phrase rather than the exact words, and are sorted by relevance score. Hover over the Exact or Fuzzy badge on any row to see exactly why it matched.
Use the checkboxes above the results to narrow: SaMD keeps only software-only devices, AI / ML keeps only devices with AI.
Exact vs. fuzzy search: what's the difference?
Exact matches on the literal phrase (prefix search works, suffix does not). Fuzzy matches on the meaning and intent of the phrase rather than the exact words. Hover over the badge on any row to see why it matched.
You search "coronary artery calcification" and want only software devices with AI. What two filters do you apply?
Narrow by SaMD (software-only devices), then narrow by AI/ML (devices with AI).
2. The results table
Scroll right in the results table. The intended use is extracted for you — no need to open the PDF. The device story gives a high-level snapshot of what the device does and how it's used. The AI Performance sub-table shows each output name, acceptance criteria, observed values, and development/test dataset descriptions — the same format Innolitics uses for regulatory strategy outputs, and the fastest high-level fingerprint of an AI device. It is AI-generated but has been very reliable in practice.
Where do you find a device's intended use without opening the PDF?
Scroll right in the search results table. The intended use column is extracted for you; no need to dig into the 510(k) summary PDF.
What does the AI Performance sub-table show, and why is it useful?
Output name, acceptance criteria, observed values, development dataset description, and test dataset description. It's the same format we use for regulatory strategy output and Fast 510(k) input, and the fastest high-level fingerprint of an AI device. AI-generated but reliable in practice.
3. Judging fuzzy relevance
Fuzzy results trail off in relevance as you scroll. Use three signals to decide how far down to go: the fuzzy badge explanations, the intended use column, and whether your target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, you're past the relevant zone. A top hit with a low score (~0.4) and a stretched explanation is a hint the closest predicates are far away — the project may be headed for De Novo. Note the fuzzy search is a pattern match: it doesn't handle negation ("not") well, and hardware devices can appear — filter by SaMD/AI ML to cut them.
How do you judge how far down fuzzy search results to go?
Use the relevancy signals: the fuzzy badge explanations, the intended use column, and whether the target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, results are trailing off in relevancy.
4. Device detail page: chat and citations
Click a device name to open its detail page: device facts on the left, a chat window on the right. Ask something like "Describe the training data". The answer carries little citation bubbles — click one to jump to the highlighted passage in the source PDF, so you can verify every AI answer against the document. There's also a Download PDF button for sharing.
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Reading rule for every project: how many summaries do you read in full?
At least the three most relevant 510(k) or De Novo summaries, in full. After that, use targeted chat questions to confirm your memory quickly. The tool supports this professional habit — it doesn't replace it.
5. Side-by-side comparison
Select multiple rows in the results table (aim for under ~10), then open the PDF Viewer tab. Ask one question — it goes to all selected devices in parallel, each with citations. This is the fastest way to compare and contrast devices: training data, PCCP scope, how they handled adding new scanners, and so on.
What does the side-by-side PDF viewer mode do?
Select multiple devices, open the PDF viewer tab, and ask one question (e.g., "Describe the training data"). It queries all selected devices simultaneously with citations, so you can compare and contrast quickly.
6. Collections
With rows selected, go to the Collections tab and create a labeled collection (e.g., "Cobb Angle Project"). Reload that selection any time — before a client call, pull up the collection and ask questions across all of its devices at once.
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What can you do from the regulations tree view?
Browse product codes and regulation numbers, read the identification text and special controls, browse sibling product codes, open device PDFs on the right, and search by product code or regulation number at the top of the tree.
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Click Show Chart and segment by regulation number (or product code) to see which regulations dominate your result set. Clicking a regulation takes you into the regulations tree. Great for spotting that most matches are, say, hardware laparoscopic devices — a cue to go back and filter.
How do you see which regulations dominate a search result set?
Click "Show Chart" and segment by Regulation Number. Clicking a regulation takes you to the regulations tree.
9. The predicate graph
Open the Predicates tab for a family-tree view of predicate relationships. Click a node to trace its parents and children; selections from search carry over pre-selected. Commonly predicated devices are worth reading — a lot of people predicated them for a reason. The visual lineage is also handy on client calls, e.g. to show how a predicate family evolved and justify why your predicate still holds.
In the predicate graph, why are commonly predicated devices worth reading?
A lot of people predicated them for a reason. Clicking a node traces parents and children, and selections from search carry over pre-selected.
10. Embeddings: the galaxy map
The Embeddings tab plots every matching document in a 2-D "galaxy map" where semantically similar devices cluster together. Hover or click clusters to explore, and let AI label the clusters for you. Embeddings beat product codes for grouping: two devices can carry different product codes (LLZ vs. QIH) yet do the same thing — the embedding captures the meaning of the intended use and device story. This is also exactly how retrieval-augmented generation (RAG) works under the hood, and it makes a great visual on client calls.
Try it yourself
Head to the search page and work through a few of these AI/ML fuzzy searches to build intuition: perivascular fat on CT · aortic valve calcification opportunistic screening on noncontrast CT · breast cancer prediction on digital pathology slides · autism detection · gestational age prediction · a hearing aid that can also detect a pulse · foundation model based analysis of ECG · large language models · penetration test. Watch how the relevance scores, intended use, and AI Performance tables tell you when results stop being meaningful.