ETEST® is a manual, quantitative technique for the determination of antimicrobial susceptibility of non-fastidious Gram-negative and Gram-positive aerobic bacteria and fastidious bacteria. The system comprises a predefined antibiotic gradient which is used to determine the Minimum Inhibitory Concentration (MIC, in μg/mL) of different antimicrobial agents against microorganisms tested on agar media after overnight incubation. Testing with ETEST® Gepotidacin (GEP) (0.016-256 μg/mL) is indicated for Enterobacterales, Staphylococcus saprophyticus, Enterococcus faecalis and Neisseria gonorrhoeae, as recognized by the FDA Susceptibility Test Interpretive Criteria (STIC). ETEST® Gepotidacin (GEP) (0.016-256 μg/mL) demonstrated acceptable performance with the following microorganisms: • Escherichia coli • Staphylococcus saprophyticus • Enterococcus faecalis • Neisseria gonorrhoeae
Device Story
ETEST is a manual, quantitative antimicrobial susceptibility test. Input: bacterial isolates from clinical samples. Operation: inert plastic strip with predefined exponential antibiotic gradient (gepotidacin 0.016-256 µg/mL) applied to inoculated agar surface. Principle: antibiotic diffuses into agar, forming stable gradient; bacterial growth inhibition creates symmetrical ellipse. Output: MIC value (µg/mL) read manually at intersection of inhibition ellipse and strip. Used in clinical microbiology laboratories. Healthcare providers use MIC to determine susceptibility (S, I, R) based on FDA STIC breakpoints, guiding antibiotic therapy selection. Benefits: provides quantitative susceptibility data to inform clinical decision-making for bacterial infections.
Clinical Evidence
Performance evaluated via comparison to CLSI M07 broth microdilution reference method using clinical isolates and challenge strains. Total N=903. Results: E. coli (N=383, 96.6% EA, 99.7% CA); S. saprophyticus (N=110, 99.1% EA, 100% CA); E. faecalis (N=110, 98.2% EA, 100% CA); N. gonorrhoeae (N=300, 96.0% EA, 99.3% CA). Reproducibility was 100% for all species. Quality control results were within expected ranges >95% of the time.
Technological Characteristics
Thin, inert, non-porous plastic strip with predefined antibiotic gradient. Quantitative MIC determination via inhibition ellipse on agar media. Manual test system. No energy source required. No software or electronic components.
Indications for Use
Indicated for determination of antimicrobial susceptibility of Enterobacterales, Staphylococcus saprophyticus, Enterococcus faecalis, and Neisseria gonorrhoeae. Specifically validated for Escherichia coli, Staphylococcus saprophyticus, Enterococcus faecalis, and Neisseria gonorrhoeae.
Regulatory Classification
Identification
An antimicrobial susceptibility test powder is a device that consists of an antimicrobial drug powder packaged in vials in specified amounts and intended for use in clinical laboratories for determining in vitro susceptibility of bacterial pathogens to these therapeutic agents. Test results are used to determine the antimicrobial agent of choice in the treatment of bacterial diseases.
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FDA U.S. FOOD & DRUG ADMINISTRATION
# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY
ASSAY ONLY
## I Background Information:
A 510(k) Number
K260477
B Applicant
bioMérieux SA
C Proprietary and Established Names
ETEST Gepotidacin (GEP) (0.016-256 µg/mL)
D Regulatory Information
| Product Code(s) | Classification | Regulation Section | Panel |
| --- | --- | --- | --- |
| JWY | Class II | 21 CFR 866.1640
Antimicrobial susceptibility test powder. | MI - Microbiology |
## II Submission/Device Overview:
A Purpose for Submission:
To obtain a substantial equivalence determination for the ETEST with gepotidacin at concentrations of 0.016-256 µg/mL for susceptibility testing of gram-positive and gram-negative organisms.
B Measurand:
Gepotidacin 0.016-256 µg/mL
C Type of Test:
Quantitative Antimicrobial Susceptibility Test growth-based detection
Food and Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993-0002
www.fda.gov
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K260447 - Page 2 of 12
# III Intended Use/Indications for Use:
## A Intended Use(s):
See Indications for Use below.
## B Indication(s) for Use:
ETEST is a manual, quantitative technique for the determination of antimicrobial susceptibility of non-fastidious Gram-negative and Gram-positive aerobic bacteria and fastidious bacteria. The system comprises a predefined antibiotic gradient which is used to determine the Minimum Inhibitory Concentration (MIC, in $\mu \mathrm{g} / \mathrm{mL}$) of different antimicrobial agents against microorganisms tested on agar media after overnight incubation.
Testing with ETEST Gepotidacin (GEP) (0.016-256 $\mu \mathrm{g} / \mathrm{mL}$) is indicated for Enterobacterales, *Staphylococcus saprophyticus*, *Enterococcus faecalis* and *Neisseria gonorrhoeae*, as recognized by the FDA Susceptibility Test Interpretive Criteria (STIC).
ETEST Gepotidacin (GEP) (0.016-256 $\mu \mathrm{g} / \mathrm{mL}$) demonstrated acceptable performance with the following microorganisms:
- *Escherichia coli*
- *Staphylococcus saprophyticus*
- *Enterococcus faecalis*
- *Neisseria gonorrhoeae*
## C Special Conditions for Use Statement(s):
Rx – For prescription use only
Due to unacceptable categorical agreement (CA below 90%) and the occurrence of two (2) very major errors (2/11; 18.1%), *Klebsiella pneumoniae* should not be tested with the ETEST Gepotidacin (GEP) (0.016-256 $\mu \mathrm{g} / \mathrm{mL}$) and should be tested by an alternative method.
The ability of the ETEST Gepotidacin (GEP) (0.016-256 $\mu \mathrm{g} / \mathrm{mL}$) to detect resistance or non-susceptibility with the following organisms is unknown because an insufficient number of resistant or non-susceptible isolates were encountered at the time of comparative testing: *Escherichia coli*, *Staphylococcus saprophyticus*, *Enterococcus faecalis*.
## D Special Instrument Requirements:
Manual reading only.
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K260447 - Page 3 of 12
# IV Device/System Characteristics:
## A Device Description:
ETEST is a thin, inert and non-porous plastic strip carrying the minimum inhibitory concentration (MIC) reading scale in $\mu \mathrm{g} / \mathrm{mL}$ on one side and a predefined antibiotic gradient on the other side.
The ETEST gradient technology is based on a combination of the concepts of dilution and diffusion principles for susceptibility testing.
The ETEST is used to determine the antimicrobial susceptibility of bacteria. One side of the strip carries the MIC reading scale expressed in $\mu \mathrm{g} / \mathrm{mL}$. The other side of the strip contains a predefined continuous exponential gradient of antibiotic concentrations.
ETEST Gepotidacin contains a range of gepotidacin concentrations from 0.016 to $256~\mu \mathrm{g / mL}$.
## B Principle of Operation:
When the ETEST strip is applied to an agar surface inoculated with bacteria, the preformed antibiotic gradient immediately transfers into the agar matrix, thereby forming a stable, continuous and exponential gradient of antibiotic concentrations directly underneath the strip. As bacteria growth becomes visible during incubation, a symmetrical inhibition ellipse centered along the strip appears. After incubation, the MIC value is read from the scale in terms of $\mu \mathrm{g} / \mathrm{mL}$ at the point of complete inhibition of bacterial growth, i.e., where the pointed end of the ellipse intersects the strip. Since ETEST generates MIC values which may fall between two-fold dilutions for interpretation, the MIC value read must be recorded as the next highest two-fold dilution.
# V Substantial Equivalence Information:
## A Predicate Device Name(s):
ETEST Fosfomycin (FO) (0.032-512 $\mu \mathrm{g / mL}$)
## B Predicate 510(k) Number(s):
K210757
## C Comparison with Predicate(s):
| Device & Predicate Device(s): | Device K260447 | Predicate K210757 |
| --- | --- | --- |
| Device Trade Name | ETEST Gepotidacin (GEP) (0.016-256 μg/mL) | ETEST Fosfomycin (FO) (0.032-512 μg/mL) |
| General Device Characteristic Similarities | | |
| Intended Use | ETEST is a manual, quantitative | Same |
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K260447 - Page 4 of 12
| Device & Predicate Device(s): | Device K260447 | Predicate K210757 |
| --- | --- | --- |
| | technique for the determination of antimicrobial susceptibility of non-fastidious Gram-negative and Gram-positive aerobic bacteria and fastidious bacteria. The system comprises a predefined antibiotic gradient which is used to determine the Minimum Inhibitory Concentration (MIC, in µg/mL) of different antimicrobial agents against microorganisms tested on agar media after overnight incubation. | |
| Test Methodology | Quantitative antimicrobial susceptibility test to determine the in vitro susceptibility of microorganisms | Same |
| Test Design | Predefined exponential gradient of the dried and stabilized antibiotic covers a continuous range of two-fold dilutions of the conventional MIC method | Same |
| Inoculum | Isolated colonies from culture in a suspension equivalent to 0.5 McFarland. Inoculum is applied to agar with swab manually or with rotation plate for even distribution of inoculum. | Same |
| Inoculation Method | Manual | Same |
| Read Method | Manual; the point where the edge of the ellipse intersects the test strip. | Same |
| Results | MIC (µg/mL) | Same |
| **General Device Characteristic Differences** | | |
| Antimicrobial Agents | Gepotidacin | Fosfomycin |
| Drug Concentration Range | 0.016-256 µg/mL | 0.032-512 µg/mL |
| Tested Species | Escherichia coli, Staphylococcus saprophyticus, Enterococcus faecalis and Neisseria gonorrhoeae | Escherichia coli, Enterococcus faecalis |
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K260447 - Page 5 of 12
# 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) with a breakpoint change protocol that was reviewed and accepted by FDA in submission K250274 cleared on April 30, 2025. This protocol addresses future revisions to device labeling in response to breakpoint changes that are recognized on the FDA STIC webpage (https://www.fda.gov/Drugs/DevelopmentApprovalProcess/DevelopmentResources/ucm410971.htm). The protocol outlined the specific procedures and acceptance criteria that bioMérieux intends to use to evaluate the ETEST Gepotidacin (GEP) (0.016-256 µg/mL) when revised breakpoints for the indicated drug are published on the FDA STIC webpage. The breakpoint change protocol included with the submission indicated that if specific criteria are met, bioMérieux will update the ETEST Gepotidacin (GEP) (0.016-256 µg/mL) label to include (1) the new breakpoints, (2) an updated performance section after re-evaluation of data in this premarket notification with the new breakpoints, and (3) any new limitations as determined by their evaluation.
## VI Standards/Guidance Documents Referenced:
- FDA Class II Special Controls Guidance Document: Antimicrobial Susceptibility (AST) Systems; Guidance for Industry and FDA (Issued August 28, 2009).
- CLSI M07 12th Edition - Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically.
- CLSI M100 35th Edition - Performance Standards for Antimicrobial Susceptibility Testing.
## VII Performance Characteristics (if/when applicable):
### A Analytical Performance:
1. **Precision/Reproducibility:**
Reproducibility testing was conducted at three sites using 26 on-scale isolates (10 E. coli, 2 K. pneumoniae, 2 E. faecalis, 2 S. saprophyticus, and 10 N. gonorrhoeae). Each isolate was tested in triplicate over three days for a total of at least 270 data points. The mode MIC value was determined for each isolate, and the reproducibility was calculated based on the number of MIC values that fell within ±1 doubling dilution of the mode. The testing resulted in overall reproducibility of 100% for both the best and worst cases. The results were acceptable.
2. **Linearity:**
N/A
3. **Analytical Specificity/Interference:**
N/A
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4. Detection Limit and Assay Reportable Range:
N/A
5. Traceability, Stability, Expected Values (Controls, Calibrators, or Methods):
## Inoculum Density Check:
The inoculum was prepared to achieve turbidity equivalent to a 0.5 McFarland standard. Colony counts were performed periodically at each site for all QC replicates, from at least one replicate of each reproducibility isolate on each of the three days of testing, and from a minimum of 10% of the contemporary clinical isolates tested. The inoculum densities were acceptable.
## Purity Check:
Verification of isolate purity was conducted on all clinical, challenge, QC and reproducibility organism suspensions for each ETEST and from each growth control well of the broth microdilution reference panel. All organism suspensions for both the broth microdilution reference panels and ETEST were pure.
## Growth or Device Failure:
No device failures occurred in the ETEST Gepotidacin (GEP) (0.016-256 µg/mL) clinical trial.
## Quality Control Testing:
The CLSI-recommended quality control (QC) strains Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 29213 and Neisseria gonorrhoeae ATCC 49226 were tested at a minimum of 20 times per site. The QC strains were tested using both ETEST and broth microdilution (BMD) reference methods. The results are summarized in Table 1.
Table 1. Quality Control Test Results for ETEST Gepotidacin (GEP)
| QC Organism | Expected Range (μg/mL) | Concentration (μg/mL) | Reference BMD (All sites) | ETEST (All sites) |
| --- | --- | --- | --- | --- |
| Escherichia coli ATCC 25922 | 1-4 | <1 | | |
| | | 1 | 57 | 25 |
| | | 2 | 25 | 61 |
| | | 4 | 1 | 0 |
| | | >4 | | |
| Enterococcus faecalis ATCC 29212 | 1-4 | <1 | | |
| | | 1 | 28 | 11 |
| | | 2 | 43 | 73 |
| | | 4 | 10 | 0 |
| | | >4 | | |
| Staphylococcus aureus ATCC 29213 | 0.125-1 | <0.125 | | |
| | | 0.125 | 0 | 14 |
| | | 0.25 | 55 | 67 |
| | | 0.50 | 25 | 4 |
K260447 - Page 6 of 12
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| QC Organism | Expected Range (μg/mL) | Concentration (μg/mL) | Reference BMD (All sites) | ETEST (All sites) |
| --- | --- | --- | --- | --- |
| | | 1 | 2 | 0 |
| | | >1 | | |
| Neisseria gonorrhoeae ATCC 49226 | 0.25-1 | <0.25 | | |
| | | 0.25 | 21 | 47 |
| | | 0.50 | 64 | 47 |
| | | 1 | 0 | 0 |
| | | >1 | | |
The Quality Control results were within the recommended range 100% of the time, which is acceptable.
6. Assay Cut-Off:
N/A
B Comparison Studies:
1. Method Comparison with Predicate Device:
Results obtained with ETEST Gepotidacin (GEP) (0.016-256 μg/mL) were compared to results obtained with the CLSI broth microdilution (BMD) reference panel for Enterobacterales, S. saprophyticus, and E. faecalis. ETEST results were compared to results obtained with the CLSI agar dilution reference method for N. gonorrhoeae. The BMD reference panel and the agar dilution reference plates were prepared and interpreted according to recommendations outlined in the CLSI M07 Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically 12th ed. At the end of incubation, the MIC value obtained from the ETEST (determined based on where the complete inhibition of growth intersects the strip) was compared to MIC results obtained with the reference methods. Testing was performed following the ETEST instructions for use.
The testing conditions for ETEST with Enterobacterales, S. saprophyticus, and E. faecalis consisted of the following:
- Inoculum: Direct colony suspension to achieve a suspension equivalent to a 0.5 McFarland standard suspension in 0.85% NaCl
- Medium: Mueller Hinton agar
- Incubation: 35±2°C for 16-20 hours in aerobic conditions
The testing conditions for ETEST with N. gonorrhoeae consisted of the following:
- Inoculum: Direct colony suspension to achieve a suspension equivalent to a 0.5 McFarland standard suspension in Mueller Hinton Broth
- Medium: GC chocolate agar with defined supplements
- Incubation: 35±2°C for 20-24 hours in 5% CO₂ conditions
Clinical testing was performed at three external sites (two US sites and one OUS site) and one internal site. A total of 903 isolates (763 clinical isolates and 140 challenge isolates) were
K260447 - Page 7 of 12
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tested (including 383 Escherichia coli, 110 Staphylococcus saprophyticus, 110 Enterococcus faecalis, and 300 Neisseria gonorrhoeae). The clinical testing included 24.1% contemporary (218/903; isolated no longer than 6 months prior to testing) and 60.4% stock (545/903; no time limit on time from isolation prior to testing) clinical isolates. A total of 140 challenge isolates were also evaluated at one internal site using ETEST Gepotidacin (GEP) and the reference methods.
The performance of 903 clinical and challenge isolates is summarized in Table 2.
Table 2. Performance of ETEST Gepotidacin (GEP)*
| | Tot* | No. EA | EA % | Eval Tot | No. Eval EA | Eval EA % | CA Tot | CA % | No. R | No. S | min | maj | vmj |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Enterobacterales (E. coli)[Breakpoints (μg/mL): ≤ 16 (S), 32 (I), ≥64 (R)] | | | | | | | | | | | | | |
| Clinical | 307 | 295 | 96.1 | 307 | 295 | 96.1 | 306 | 99.6 | 0 | 303 | 1 | 0 | 0 |
| Challenge | 76 | 75 | 98.7 | 76 | 75 | 98.7 | 76 | 100 | 0 | 76 | 0 | 0 | 0 |
| Combined | 383 | 370 | 96.6 | 383 | 370 | 96.6 | 382 | 99.7 | 0 | 379 | 1 | 0 | 0 |
| Staphylococcus saprophyticus[Breakpoints (μg/mL): ≤ 0.25 (S)] | | | | | | | | | | | | | |
| Clinical | 104 | 103 | 99.0 | 104 | 103 | 99.0 | 104 | 100 | 0 | 104 | 0 | 0 | 0 |
| Challenge | 6 | 6 | 100 | 6 | 6 | 100 | 6 | 100 | 0 | 6 | 0 | 0 | 0 |
| Combined | 110 | 109 | 99.1 | 110 | 109 | 99.1 | 110 | 100 | 0 | 110 | 0 | 0 | 0 |
| Enterococcus faecalis[Breakpoints (μg/mL): ≤ 4 (S)] | | | | | | | | | | | | | |
| Clinical | 104 | 102 | 98.1 | 104 | 102 | 98.1 | 104 | 100 | 0 | 104 | 0 | 0 | 0 |
| Challenge | 6 | 6 | 100 | 6 | 6 | 100 | 6 | 100 | 0 | 6 | 0 | 0 | 0 |
| Combined | 110 | 108 | 98.2 | 110 | 108 | 98.2 | 110 | 100 | 0 | 110 | 0 | 0 | 0 |
| Neisseria gonorrhoeae[Breakpoints (μg/mL): ≤ 1 (S), 2 (I), ≥4 (R)] | | | | | | | | | | | | | |
| Clinical | 248 | 238 | 96.0 | 248 | 238 | 96.0 | 247 | 99.6 | 1 | 244 | 1 | 0 | 0 |
| Challenge | 52 | 50 | 96.2 | 52 | 50 | 96.5 | 51 | 98.1 | 6 | 44 | 1 | 0 | 0 |
| Combined | 300 | 288 | 96.0 | 300 | 288 | 96 | 298 | 99.3 | 7 | 288 | 2 | 0 | 0 |
* Testing with the optional ETEST tools was not evaluated during the ETEST Gepotidacin clinical studies.
EA - Essential Agreement
CA - Category Agreement
S - Susceptible
R - Resistant
Eval - Evaluable MICs
min - Minor Errors
maj - Major Errors
vmj - Very Major Errors
Essential agreement (EA) occurs when the MIC result of the reference method and that of the ETEST Gepotidacin (GEP) are within plus or minus one serial two-fold dilution of the antibiotic. Evaluable results are those that are on scale for both the reference method and the ETEST Gepotidacin (GEP) or those in which an off-scale result is at least two doubling dilutions from the on-scale result. Category agreement (CA) occurs when the interpretation of the result of the reference method agrees exactly with the interpretation of the ETEST Gepotidacin (GEP).
K260447 - Page 8 of 12
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K260447 - Page 9 of 12
# Enterobacteriales
ETEST Gepotidacin (GEP) (0.016-256 µg/mL) performance for 383 Escherichia coli isolates (clinical and challenge) was acceptable with an EA of 96.6% and CA of 99.7%. There was one (1) minor error and no major or very major errors.
An insufficient number of resistant Escherichia coli isolates were available for evaluation. The sponsor included the following limitation in the device labeling:
The ability of the ETEST Gepotidacin (GEP) (0.016-256 µg/mL) to detect resistance or non-susceptibility with the following organisms is unknown because an insufficient number of resistant or non-susceptible strains were encountered at the time of comparative testing: Escherichia coli
During the clinical study, 115 Klebsiella pneumoniae isolates (clinical and challenge) were tested with ETEST Gepotidacin (GEP) (0.016-256 µg/mL). The EA was 90.4% and the CA was 80.9%. There were 21 minor, no major, and two (2/11=18.1%) very major errors, which is not acceptable. Reporting limitations were not appropriate to mitigate the unacceptable very major error rate. The sponsor removed this organism from the Indications for Use, and the following limitation is included in the device labeling to address testing of this species:
Due to an unacceptable categorical agreement (CA below 90%) and the occurrence of two very major errors (2/11;18.1%), Klebsiella pneumoniae should not be tested with the ETEST Gepotidacin (GEP) (0.016-256 µg/mL) and should be tested by an alternative method.
# Staphylococcus saprophyticus
ETEST Gepotidacin (GEP) (0.016-256 µg/mL) performance for 110 Staphylococcus saprophyticus isolates (clinical and challenge) is acceptable with an EA of 99.1% and CA of 100%. There were no potential minor, potential major, or potential very major errors. Errors are considered potential since no interpretive category other than "susceptible only" is defined for S. saprophyticus with gepotidacin.
An insufficient number of non-susceptible Staphylococcus saprophyticus isolates were available for evaluation. The sponsor included the following limitation in the device labeling:
The ability of the ETEST Gepotidacin (GEP) (0.016-256 µg/mL) to detect resistance or non-susceptibility with the following organisms is unknown because an insufficient number of resistant or non-susceptible strains were encountered at the time of comparative testing: Staphylococcus saprophyticus.
# Enterococcus faecalis
ETEST Gepotidacin (GEP) (0.016-256 µg/mL) performance for 110 Enterococcus faecalis isolates (clinical and challenge) is acceptable with an EA of 98.2% and CA of 100%. There were no potential minor, potential major, or potential very major errors. Errors are considered potential since no interpretive category other than "susceptible only" is defined for E. faecalis with gepotidacin.
An insufficient number of non-susceptible Enterococcus faecalis isolates were available for evaluation. The sponsor included the following limitation in the device labeling:
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The ability of the ETEST Gepotidacin (GEP) (0.016-256 μg/mL) to detect resistance or non-susceptibility with the following organisms is unknown because an insufficient number of resistant or non-susceptible strains were encountered at the time of comparative testing: Enterococcus faecalis.
## Neisseria gonorrhoeae
ETEST Gepotidacin (GEP) (0.016-256 μg/mL) performance for 300 Neisseria gonorrhoeae isolates (clinical and challenge) is acceptable with an EA of 96.0% and CA of 99.3%. There were two (2) minor, no major, or very major errors.
## MIC Trending Analysis
Using the combined clinical and challenge data, an analysis of trending was conducted for all indicated species. Results are analyzed to determine if species-related trends were observed (Table 3). This trending calculation considers MIC values that are determined to be one or more doubling dilutions lower or higher compared to the reference method irrespective of whether the device MIC values are on-scale or not. Results that are not clearly at least one dilution lower, at least one dilution higher or in exact agreement with the CLSI reference method are not considered in the trending analysis.
Species for which the difference between the percentage of isolates with higher vs. lower readings was ≥ 30% and for which the confidence interval was determined to be statistically significant were considered to show evidence of trending. Trending that provides higher or lower MIC values compared to the reference is addressed in labeling.
Table 3. Trending Observed with ETEST Gepotidacin (GEP)
| Organism Name | Total Evaluable for Trending | ≥ 1 Dilution lower No. (%) | Exact No. | ≥ 1 Dilution Higher No. (%) | Percent Difference (CI)* | Trending Noted |
| --- | --- | --- | --- | --- | --- | --- |
| Escherichia coli | 383 | 94 (24.5%) | 237 | 52 (13.6%) | -11% (-16%, -5%) | No |
| Staphylococcus saprophyticus | 110 | 37 (33.7%) | 68 | 5 (4.6%) | -29% (-39%, -19%) | No |
| Enterococcus faecalis | 110 | 30 (27.3%) | 69 | 11 (10%) | -17% (-27%, -7%) | No |
| Neisseria gonorrhoeae | 300 | 108 (36%) | 150 | 42 (14%) | -22% (-29%, -15%) | No |
Analysis of trending indicated that MIC values tended to be in exact agreement with the reference MIC values. No trending was noted.
## Testing/Reporting MICs For Species Not Listed in Indications for Use
For this review, the interpretative criteria are applied to the organisms/organism groups 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 added in the precautions section of labeling to address testing and reporting of species not listed in the device Indications for Use:
K260447 - Page 10 of 12
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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 labelling for specific antimicrobial drugs provides the uses for which the antimicrobial drug is approved.
## Inoculator and ETEST Strip Applicator Options
Culture media plates for ETEST can be inoculated and streaked by swabs manually or with the RETRO C80 inoculator. ETEST strips can be applied onto inoculated media using forceps, the NEMA C88 vacuum pen or the automatic Applicator SIMPLEX C76.
The ETEST studies for gepotidacin used manual inoculation with swabs and applied ETEST strips with forceps at all test sites. The following statement is included as a footnote to the performance table in the device labeling:
Testing with the optional ETEST tools was not evaluated during the ETEST Gepotidacin clinical studies.
## Resistant Isolates
A total of seven (7) Neisseria gonorrhoeae resistant isolates (one clinical and six challenge) were available in the ETEST Gepotidacin performance evaluation studies.
## Resistance Mechanism Characterization
Challenge isolates of Escherichia coli, Enterococcus faecalis, and Neisseria gonorrhoeae harboring various mechanisms of resistance were evaluated with ETEST Gepotidacin (GEP) (0.016-256 µg/mL). The following antimicrobial resistance mechanisms were evaluated: penicillinase, ciprofloxacin resistance, acquired carbapenemases (i.e., KPC, NDM, OXA-, and OXA-48), reduced permeability, high-level Amp-C β-lactamase, ESBL, and vancomycin resistance enterococci (VanA and VanB).
2. Matrix Comparison:
N/A
## C Clinical Studies:
1. Clinical Sensitivity:
N/A
2. Clinical Specificity:
N/A
3. Clinical Cut-Off
N/A
K260447 - Page 11 of 12
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4. Other Clinical Supportive Data (When 1. and 2. Are Not Applicable):
N/A
## D Expected Values/Reference Range:
The FDA recognized susceptibility interpretive criteria for gepotidacin are listed in Table 4.
Table 4. FDA Recognized Interpretive Criteria for Gepotidacin
| | Minimum Inhibitory Concentration (μg/mL)a | | |
| --- | --- | --- | --- |
| Organisms | S | I | R |
| Enterobacterales | ≤16 | 32 | ≥64 |
| Staphylococcus saprophyticus | ≤0.25 | - | - |
| Enterococcus faecalis | ≤4 | - | - |
| Neisseria gonorrhoeae | ≤1 | 2 | ≥4 |
aAccording to the FDA STIC Webpage https://www.fda.gov/drugs/development-resources/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.
K260447 - Page 12 of 12
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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.
How do you verify an AI chat answer on the device detail page?
Click the citation bubbles to jump to the relevant highlight in the source document.
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.
How do you save a set of selected devices for later use?
Select the rows, go to the Collections tab, and create a labeled collection (e.g., "Cobb Angle Project"). You can reload the selection anytime and carry it into the PDF viewer and other tabs that support selections.
7. Product codes and the regulations tree
Click a product code in the results to jump to it in the regulations tree — identification text, sibling product codes, and devices you can open in a PDF viewer on the right. Click a regulation number to see its identification, special controls, and related product codes. You can also search by product code or regulation number at the top of the tree. Always read the special controls if any exist for your device — it broadens your search and sharpens pre-kickoff research.
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.
8. Chart view
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.