Selux AST System; Model AST Gen 1.0

K211748 · Selux Diagnostics, Inc. · LON · Apr 19, 2023 · Microbiology

Device Facts

• Record ID: K211748
• Device Name: Selux AST System; Model AST Gen 1.0
• Applicant: Selux Diagnostics, Inc.
• Product Code: LON · Microbiology
• Decision Date: Apr 19, 2023
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.1645
• Device Class: Class 2

Intended Use

The Selux AST System is intended to be used for the automated quantitative or qualitative susceptibility testing for most clinically significant aerobic microorganisms. The Selux AST System does not provide organism identification. The Selux Gram-Negative Panel is intended for use with the Selux AST System as an in vitro test to determine the susceptibility of isolated colonies of specific gram-negative bacilli to specific antimicrobial agents when used as instructed.

Device Story

System performs automated antimicrobial susceptibility testing (AST) on isolated bacterial colonies. Components: Sample Prep Station, Inoculator, Analyzer, workstation. Workflow: User prepares sample; system inoculates 384-well panels; analyzer monitors growth via fluorescence/absorbance. Principle: Growth-based detection using serial two-fold dilution; metabolic assays (viability/surface binding) quantify growth after sufficient replication threshold. Algorithm: Species-specific MIC determination; requires organism ID (manual or LIS download) for result reporting. Output: MIC values and categorical interpretations (S, I, R, NS). Used in clinical laboratories to guide antimicrobial therapy; benefits patient by providing rapid susceptibility results (<6 hours) to inform treatment decisions.

Clinical Evidence

Clinical performance evaluated using 1,401 clinical isolates (426 contemporary, 975 stock) and 222 challenge isolates across three sites. Compared against triplicate broth microdilution reference method. Evaluated 24 antimicrobials against Enterobacterales, A. baumannii complex, and P. aeruginosa. Results demonstrated high essential agreement (EA) and categorical agreement (CA) across all tested antimicrobial-organism combinations. Reproducibility studies (inter-site and intra-site) showed ≥89% performance.

Technological Characteristics

Automated growth-based detection system using 384-well panels. Methodology: Serial two-fold dilution. Sensing: Fluorescence and optical absorbance for metabolic assays (viability/surface binding). Connectivity: LIS integration for ID download. Software: Algorithm-based MIC determination. Sterilization: Not specified.

Indications for Use

Indicated for automated susceptibility testing of isolated colonies of specific gram-negative bacilli (Enterobacterales, Acinetobacter baumannii complex, Pseudomonas aeruginosa) to specific antimicrobial agents. Requires Gram stain information for panel selection; organism ID required for final susceptibility reporting.

Regulatory Classification

Identification

A fully automated short-term incubation cycle antimicrobial susceptibility system is a device that incorporates concentrations of antimicrobial agents into a system for the purpose of determining in vitro susceptibility of bacterial pathogens isolated from clinical specimens. Test results obtained from short-term (less than 16 hours) incubation are used to determine the antimicrobial agent of choice to treat bacterial diseases.

Special Controls

*Classification.* Class II (special controls). The special control for this device is FDA's guidance document entitled “Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA.”

Predicate Devices

• BD Phoenix Automated Microbiology System- Ceftaroline 0.0156-4 µg/mL (K190905)

Submission Summary (Full Text)

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April 19, 2023

Selux Diagnostics, Inc % Patricia Shrader Regulatory Consultant PBO Consulting 2212 East Pratt Street Baltimore, Maryland 21231

Re: K211748

Trade/Device Name: Selux AST System; Model AST Gen 1.0 Regulation Number: 21 CFR 866.1645 Regulation Name: Fully Automated Short-Term Incubation Cycle Antimicrobial Susceptibility System Regulatory Class: Class II Product Code: LON, LTT, LTW Dated: June 4, 2021 Received: June 7, 2021

Dear Patricia Shrader:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's

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requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801 and Part 809); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.

For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email ([e-mail]) or phone [phone] or 301-796-7100).

Sincerely,

# Ribhi Shawar -S

Ribhi Shawar, Ph.D. (ABMM) Branch Chief. General Bacteriology and Antimicrobial Susceptibility Branch Division of Microbiology Devices OHT7: Office of In Vitro Diagnostics Office of Product Evaluation and Quality Center for Devices and Radiological Health

Enclosure

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# Indications for Use

510(k) Number (if known) K211748

Device Name Selux AST System

#### Indications for Use (Describe)

#### Intended Use:

The Selux AST System is intended to be used for the automated quantitative susceptibility testing for most clinically significant aerobic microorganisms. The Selux AST System does not provide organism identification.

#### Indications for Use:

The Selux Gram-Negative Panel is intended for use with the Selux AST System as an in vitro test to determine the susceptibility of isolated colonies of specific gram-negative bacilli to specific antimicrobial agents when used as instructed.

The Selux Gram-Negative Panel is a quantitative test for the following antimicrobial agents with the specific organisms identified below:

- Amikacin: Pseudomonas aeruginosa
- Amoxicillin-Clavulanate: Escherichia coli, Klebsiella species (including K. oxytoca, K. pneumoniae), Proteus ● mirabilis
- Ampicillin: Escherichia coli, Proteus mirabilis ●
- Ampicillin-Sulbactam: Acinetobacter baumannii complex, Escherichia species (including K. oxytoca, ● K. pneumoniae), Proteus mirabilis, Proteus vulgaris
- Aztreonam: Escherichia coli ●
- Cefazolin: Escherichia coli, Klebsiella pneumoniae ●
- Cefepime: Citrobacter freundii complex, Citrobacter cloacae complex, Escherichia coli, . Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Morganii, Proteus mirabilis, Proteus vulgaris, Serratia marcescens
- Cefoxitin: Escherichia coli, Klebsiella species (including K. oxytoca, K. pneumoniae), Morganii
- Ceftazidime: Citrobacter species (including C. freundii complex, C. koseri), Enterobacter cloacae complex, ● Escherichia coli, Klebsiella species (including K. aerogenes, K. pneumoniae), Proteus mirabilis, Proteus vulgaris, Serratia marcescens
- Ceftazidime-Avibactam: Citrobacter freundii complex, Citrobacter koseri, Enterobacter cloacae complex, ● Escherichia coli, Klebsiella aerogenes, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Pseudomonas aeruginosa, Serratia marcescens
- Ceftriaxone: Citrobacter freundii complex, Citrobacter koseri, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Proteus mirabilis
- . Ciprofloxacin: Citrobacter freundii complex, Citrobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Morganii, Proteus mirabilis, Proteus vulgaris, Pseudomonas aeruginosa
- Eravacycline: Citrobacter freundii complex, Enterobacter cloacae complex, Escherichia oxytoca ●
- Ertapenem: Citrobacter freundii complex, Citrobacter koseri, Klebsiella oxytoca, Klebsiella ● pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Serratia marcescens
- Gentamicin: Citrobacter species (including C. freundii complex, C. koseri), Enterobacter cloacae complex, Escherichia coli, Klebsiella species (including K. aerogenes, K. oxytoca, K. pneumoniae), Proteus species (including P. mirabilis, P. vulgaris), Pseudomonas aeruginosa, Serratia marcescens
- Imipenem-Relebactam: Citrobacter freundii complex, Citrobacter koseri, Escherichia coli, Klebsiella oxytoca, Pseudomonas aeruginosa

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- Levofloxacin: Citrobacter freundii complex, Citrobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Morganii, Proteus mirabilis, Proteus vulgaris, Serratia marcescens
- . Meropenem: Citrohacter freundii complex. Citrobacter cloacae complex. Escherichia coli. Klebsiella oxvtoca, Klebsiella pneumoniae, Morganella morganii. Proteus mirabilis, Proteus vulgaris, Pseudomonas aeruginosa, Serratia marcescens
- Meropenem-Vaborbactam: Citrobacter freundii complex, Citrobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella pneumoniae, Morganella morganii, Serratia marcescens
- Minocycline: Escherichia coli, Klebsiella species (including K. aerogenes, K. oxytoca, K. pneumoniae)
- Piperacillin-Tazobactam: Citrobacter koseri, Escherichia coli, Klebsiella pneumoniae, Morganii, ● Proteus mirabilis, Proteus vulgaris
- Tobramycin: Pseudomonas aeruginosa .
- Trimethoprim-Sulfamethoxazole: Enterobacter cloacae complex, Klebsiella species (including K. aerogenes, K. oxytoca, K. pneumoniae)

Type of Use (Select one or both, as applicable)

> Prescription Use (Part 21 CFR 801 Subpart D)

Over-The-Counter Use (21 CFR 801 Subpart C)

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# 510(k) Summary for the Selux AST System, Antimicrobial Susceptibility Test System

Date prepared: April 9, 2023

#### Submitter:

Selux Diagnostics, Inc. 56 Roland St Suite 106 Charlestown, MA 02129 Tel. [phone]

#### Contact:

Eric Stern, Ph.D. Tel. [phone]

#### Subject Device

| Trade Name: | Selux AST System |
|-----------------------|------------------------------------------------------------------------------------|
| Common Name: | Antimicrobial Susceptibility Test System |
| Regulation Number: | 21 CFR 866.1645 |
| Regulation Name: | Fully automated short-term incubation cycle antimicrobial susceptibility<br>system |
| Regulatory Class: | Class II |
| Product Code: | LON, LTT, LTW |
| Classification Panel: | 83 (Microbiology) |

#### Primary Predicate Device(s)

| Trade Name: | BD Phoenix Automated Microbiology System- Ceftaroline 0.0156-4<br>µg/mL |
|-----------------------|------------------------------------------------------------------------------------|
| Manufacturer: | Becton, Dickinson and Company |
| 510(k) Reference: | K190905 |
| Common Name: | Antimicrobial Susceptibility Test System |
| Regulation Number: | 21 CFR 866.1645 |
| Regulation Name: | Fully automated short-term incubation cycle antimicrobial susceptibility<br>system |
| Regulatory Class: | Class II |
| Product Code: | LON |
| Classification Panel: | 83 (Microbiology) |

#### Device Description

The Selux AST System for antimicrobial susceptibility testing (AST) consists of a Sample Prep Station, an Inoculator, an Analyzer, a computer workstation, and the reagents and consumables required to perform AST testing. The system is operated via software that guides users through the manual sample preparation process and operates the automated Inoculator and Analyzer. The software includes an algorithm that enables the system to determine the susceptibilities of an organism to the variety of antimicrobials under test.

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The system is designed so that only Gram stain information is required to initiate testing (to select the proper antimicrobial panel, gram-negative or gram-positive). While complete system testing can be performed without species-level identification (ID), this information is required for the system to report susceptibility results. Species ID can be performed by any appropriate method and this information can be either manually input to the Selux system or automatically downloaded from the laboratory information system (LIS) at any time, once the sample ID is entered into the । ।। :: :

The system utilizes 384-well panels to provide parallel results for a large number of antimicrobials. Its average time-to-result is under 6 hours, as demonstrated in various studies.

## Principle of Operation

The Selux platform performs AST similarly to the reference broth microdilution method by first incubating samples, then quantifying microbial growth in each well of an antimicrobial dilution series after a growth period, and finally determining the MIC by comparing growth data in each well. The Selux AST test requires that the Gram type (Classification) of the organism be known prior to testing as the information is necessary to select the proper AST panel to use. The organism identification (ID) need not be known for Selux AST processing to be performed. However, the organism ID is necessary for a result to be obtained because the MIC-determining algorithm is species-specific as is the interpretative Susceptible, Intermediate, or Resistant (SIR) determination. Any FDA-cleared method may be used to provide an ID including biochemical techniques, matrixassisted laser desorption/isotherm mass spectrometry, and multiplex genetic assays.

To ensure accurate results, the Selux method initiates antimicrobial susceptibility assays only after sufficient microorganism replication has occurred. Following determination of sufficient growth, two complementary metabolic assays are performed that quantify microbial growth, namely an indicator assay to estimate the number of bacteria present and a surface binding assay. These data are input to an MIC-determining algorithm that provides results when organism IDs are available. The sufficient growth assay ensures that the metabolic reagents used for the high-sensitivity organism quantification assays are not added until after sufficient microbial growth has occurred. To get an accurate reading of microbial replication, the sufficient growth assay monitors growth in dedicated AST panel wells that contain organisms and cation-adjusted Mueller-Hinton Broth but no antimicrobials or probes. Sufficient growth assay wells are monitored by fluorescence to those wells which the standard viability assay pair resazurin/methylene blue have been added and/or by optical absorbance.

Two probe-based assays, a viability assay and a surface area assay, commence across all wells in the panel after the sufficient growth threshold has been met. Both of these assays are performed in each AST panel well, providing two complementary datasets for each well.

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# Intended Use and Indications for Use

The Selux AST System is intended to be used for the automated quantitative or qualitative susceptibility testing for most clinically significant aerobic microorganisms. The Selux AST System does not provide organism identification.

The Selux Gram-Negative Panel is intended for use with the Selux AST System as an in-vitro test to determine the susceptibility of isolated colonies of specific gram-negative bacilli to specific antimicrobial agents when used as instructed.

The Selux Gram-Negative Panel is a quantitative test for the following antimicrobial agents with the specific organisms identified below:

- . Amikacin: Pseudomonas aeruginosa
- . Amoxicillin-Clavulanate: Escherichia coli, Klebsiella species (including K. oxytoca, K. pneumoniae). Proteus mirabilis
- Ampicillin: Escherichia coli, Proteus mirabilis
- . Ampicillin-Sulbactam: Acinetobacter baumannii complex, Escherichia coli, Klebsiella species (including K. oxytoca, K. pneumoniae), Proteus mirabilis, Proteus vulgaris
- Aztreonam: Escherichia coli
- Cefazolin: Escherichia coli, Klebsiella pneumoniae
- Cefepime: Citrobacter freundii complex, Citrobacter koseri, Enterobacter cloacae . complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Serratia marcescens
- . Cefoxitin: Escherichia coli, Klebsiella species (including K. oxytoca, K. pneumoniae), Morganella morganii
- . Ceftazidime: Citrobacter species (including C. freundii complex, C. koseri), Enterobacter cloacae complex, Escherichia coli, Klebsiella species (including K. aerogenes, K. oxvtoca, K. pneumoniae), Proteus mirabilis, Proteus vulgaris, Serratia marcescens
- . Ceftazidime-Avibactam: Citrobacter freundii complex, Citrobacter koseri, Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Pseudomonas aeruginosa, Serratia marcescens
- . Ceftriaxone: Citrobacter freundii complex, Citrobacter koseri, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Proteus mirabilis
- Ciprofloxacin: Citrobacter freundii complex, Citrobacter koseri, Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Pseudomonas aeruginosa
- . Eravacycline: Citrobacter freundii complex, Enterobacter cloacae complex, Escherichia coli, Klebsiella oxytoca
- . Ertapenem: Citrobacter freundii complex, Citrobacter koseri, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Serratia marcescens

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- Gentamicin: Citrobacter species (including C. freundii complex, C. koserì), . Enterobacter cloacae complex, Escherichia coli, Klebsiella species (including K. aerogenes, K. oxytoca, K. pneumoniae), Proteus species (including P. mirabilis, P. vulgaris), Pseudomonas aeruginosa, Serratia marcescens
- . Imipenem-Relebactam: Citrobacter freundii complex, Citrobacter koseri, Escherichia coli, Klebsiella oxytoca, Pseudomonas aeruginosa
- . Levofloxacin: Citrobacter freundii complex. Citrobacter koseri, Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Serratia marcescens
- . Meropenem: Citrobacter freundii complex, Citrobacter koseri, Enterobacter cloacae complex, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Pseudomonas aeruginosa, Serratia marcescens
- . Meropenem-Vaborbactam: Citrobacter freundii complex, Citrobacter koseri, Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxvtoca. Klebsiella pneumoniae, Morganella morganii, Serratia marcescens
- . Minocycline: Escherichia coli, Klebsiella species (including K. aerogenes, K. oxytoca, K. pneumoniae)
- . Piperacillin-Tazobactam: Citrobacter koseri, Escherichia coli, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris
- . Tobramycin: Pseudomonas aeruginosa
- . Trimethoprim-Sulfamethoxazole: Enterobacter cloacae complex, Klebsiella species (including K. aerogenes, K. oxytoca, K. pneumoniae)

# Comparison of Technological Characteristics with the Predicate Device

The technological characteristics of the Selux AST System are substantially equivalent to the predicate, the BD Phoenix Automated Microbiology System- Ceftaroline 0.0156-4 ug/mL (K190905) in terms of intended use, application, user population, basic design, performance, and labeling.

| Specification | Selux AST System | K190905 |
|--------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Device Trade Name | Selux AST System | BD Phoenix Automated<br>Microbiology System-<br>Ceftaroline 0.0156-4 µg/mL |
| Indication for Use | The Selux AST System is intended to be<br>used for the automated quantitative or<br>qualitative susceptibility testing for most<br>clinically significant aerobic<br>microorganisms. The Selux AST System<br>does not provide organism identification.<br><br>The Selux Gram-Negative Panel is<br>intended for use with the Selux AST<br>System as an <i>in vitro</i> test to determine the<br>susceptibility of isolated colonies of<br>specific gram-negative bacilli to specific | The BD Phoenix Automated<br>Microbiology System is intended<br>for the <i>in vitro</i> rapid identification<br>(ID) of aerobic and facultative<br>anaerobic Gram-negative<br>bacteria. The BD Phoenix<br>Automated Microbiology System is<br>also intended for the quantitative<br>determination of antimicrobial<br>susceptibility by minimal inhibitory<br>concentration (MIC) of aerobic and<br>facultative anaerobic Gram- |
| Specification | Selux AST System | K190905 |
| | antimicrobial agents when used as<br>instructed. | negative bacteria isolates from pure<br>culture. |
| Sources of<br>Microorganisms | Bacterial colonies isolated from culture | Same |
| Technology | Automated growth-based detection | Same |
| Methodology | Determinations of MIC using serial two-<br>fold dilution format | Same |
| Read Method | Automated | Same |
| Inoculation Method | Automated | Same |
| Result Reported | Report results as minimum inhibitory<br>concentration (MIC) and categorical<br>interpretation (S, I, R, NS) | Report results as minimum<br>inhibitory concentration (MIC) and<br>categorical interpretation (S, I, R) |
| General Device Characteristic Differences | | |
| Antimicrobial Agent and<br>Reporting Range | Amikacin: ≤2 to ≥256 µg/mL<br>Amoxicillin-Clavulanate: ≤0.5 to ≥128<br>µg/mL<br>Ampicillin: ≤0.25 to ≥128 µg/mL<br>Ampicillin-Sulbactam: ≤0.5 to ≥128<br>µg/mL<br>Aztreonam: ≤0.03 to ≥128 µg/mL<br>Cefazolin: ≤0.12 to ≥128 µg/mL<br>Cefepime: ≤0.25 to ≥128 µg/mL<br>Cefoxitin: ≤1 to ≥128 µg/mL<br>Ceftazidime: ≤2 to ≥64 µg/mL<br>Ceftazidime-Avibactam: ≤0.12 to ≥64<br>µg/mL<br>Ceftriaxone: ≤0.25 to ≥32 µg/mL<br>Ciprofloxacin: ≤0.03 to ≥16 µg/mL<br>Eravacycline: ≤0.016 to ≥4 µg/mL<br>Ertapenem: ≤0.03 to ≥16 µg/mL<br>Gentamicin: ≤0.06 to ≥64 µg/mL<br>Imipenem-Relebactam: ≤0.03 to ≥128<br>µg/mL<br>Levofloxacin: ≤0.06 to ≥32 µg/mL<br>Meropenem: ≤0.5 to ≥64 µg/mL<br>Meropenem-Vaborbactam: ≤0.06 to<br>≥64 µg/mL<br>Minocycline: ≤1 to ≥64 µg/mL<br>Piperacillin-Tazobactam: ≤4 to ≥512<br>µg/mL<br>Tobramycin: ≤0.12 to ≥128 µg/mL<br>Trimethoprim-Sulfamethoxazole:<br>≤0.12 to ≥32 µg/mL | Ceftaroline: ≤0.0156 to ≥8 µg/mL |
| IVD Functions | AST | ID and AST |
| Instrument | Selux AST System | BD Phoenix Automated<br>Microbiology System |

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Despite the differences between the Selux AST System and the predicate, the overall risk and safety of system use is not affected.

## Reproducibility

Inter-site reproducibility was evaluated by testing a minimum of 25 isolates for each of the 24 antimicrobials at each of three test sites that participated in the clinical study. Each isolate was tested once at each site for a total of three results per isolate (minimum of 75 results per antimicrobial). Best-case inter-site reproducibility was ≥95% and worst-case inter-site reproducibility was ≥89% (see following table).

| Selux AST System Inter-site Reproducibility | | | | |
|---------------------------------------------|--------------------------|-----------------|--------------------------|-----------------|
| | All organisms (combined) | | Indicated organisms only | |
| Antimicrobial | Best-case (%) | Worst case (%) | Best-case (%) | Worst case (%) |
| Amikacin | 98/104 (94.2%) | 98/104 (94.2%) | 92/98 (93.9%) | 92/98 (93.9%) |
| Amoxicillin-Clavulanate | 71/72 (98.6%) | 70/72 (97.2%) | 71/72 (98.6%) | 70/72 (97.2%) |
| Ampicillin | 72/75 (96.0%) | 72/75 (96.0%) | 68/69 (98.6%) | 68/69 (98.6%) |
| Ampicillin-Sulbactam | 74/75 (98.7%) | 74/75 (98.7%) | 66/66 (100%) | 66/66 (100%) |
| Aztreonam | 77/78 (98.7%) | 75/78 (96.2%) | 77/78 (98.7%) | 75/78 (96.2%) |
| Cefazolin | 77/81 (95.1%) | 76/81 (93.8%) | 68/72 (94.4%) | 67/72 (93.1%) |
| Cefepime | 77/78 (98.7%) | 76/78 (97.4%) | 77/78 (98.7%) | 76/78 (97.4%) |
| Cefoxitin | 70/72 (97.2%) | 69/72 (95.8%) | 70/72 (97.2%) | 69/72 (95.8%) |
| Ceftazidime1 | 77/81 (95.1%) | 71/81 (87.7%) | 77/81 (95.1%) | 71/81 (87.7%) |
| Ceftazidime-Avibactam | 140/144 (97.2%) | 139/144 (96.5%) | 140/144 (97.2%) | 139/144 (96.5%) |
| Ceftriaxone | 140/141 (99.3%) | 140/141 (99.3%) | 140/141 (99.3%) | 140/141 (99.3%) |
| Ciprofloxacin | 74/75 (98.7%) | 71/75 (94.7%) | 74/75 (98.7%) | 71/75 (94.7%) |
| Eravacycline | 78/78 (100%) | 78/78 (100%) | 78/78 (100%) | 78/78 (100%) |
| Ertapenem | 143/145 (98.6%) | 143/145 (98.6%) | 143/145 (98.6%) | 143/145 (98.6%) |
| Gentamicin | 77/80 (96.3%) | 77/80 (96.3%) | 77/80 (96.3%) | 77/80 (96.3%) |
| Imipenem | 145/149 (97.3%) | 140/149 (94.0%) | 145/149 (97.3%) | 140/149 (94.0%) |
| Imipenem-Relebactam | 72/75 (96.0%) | 72/75 (96.0%) | 72/75 (96.0%) | 72/75 (96.0%) |
| Levofloxacin | 76/78 (97.4%) | 76/78 (97.4%) | 76/78 (97.4%) | 76/78 (97.4%) |
| Meropenem | 75/78 (96.2%) | 73/78 (93.6%) | 70/72 (97.2%) | 68/72 (94.4%) |
| Meropenem-Vaborbactam | 142/145 (97.9%) | 132/145 (91.0%) | 133/143 (93.0%) | 133/143 (93.0%) |
| Minocycline | 73/75 (97.3%) | 73/75 (97.3%) | 64/66 (97.3%) | 64/66 (97.3%) |
| Piperacillin-Tazobactam | 72/75 (96.0%) | 69/75 (92.0%) | 63/66 (95.5%) | 60/66 (90.9%) |
| Tobramycin | 74/78 (94.9%) | 73/78 (93.6%) | 74/78 (94.9%) | 73/78 (93.6%) |
| Trimethoprim-Sulfamethoxazole | 143/148 (96.6%) | 142/148 (95.9%) | 143/148 (96.6%) | 142/148 (95.9%) |

Intra-site reproducibility was evaluated at a single site that participated in the inter-site reproducibility testing and the clinical study. A minimum of 5 isolates for each antimicrobial were tested in triplicate at the site from three separate inoculums on three separate days for a minimum total of 45 results per antimicrobial. Best-case intra-site reproducibility was ≥95% and worst-case intra-site reproducibility was ≥89% (see following table).

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| Selux AST System Intra-site Reproducibility | | | | |
|---------------------------------------------|--------------------------|-----------------|--------------------------|-----------------|
| | All organisms (combined) | | Indicated organisms only | |
| Antimicrobial | Best-case (%) | Worst case (%) | Best-case (%) | Worst case (%) |
| Amoxicillin-Clavulanate | 63/63 (100%) | 63/63 (100%) | 63/63 (100%) | 63/63 (100%) |
| Ampicillin | 45/45 (100%) | 45/45 (100%) | 45/45 (100%) | 45/45 (100%) |
| Ampicillin-Sulbactam | 72/72 (100%) | 72/72 (100%) | 72/72 (100%) | 72/72 (100%) |
| Aztreonam | 71/74 (95.9%) | 68/74 (91.9%) | 71/74 (95.9%) | 68/74 (91.9%) |
| Cefazolin | 61/63 (96.8%) | 61/63 (96.8%) | 61/63 (96.8%) | 61/63 (96.8%) |
| Cefepime | 45/47 (95.7%) | 45/47 (95.7%) | 45/47 (95.7%) | 45/47 (95.7%) |
| Cefoxitin | 54/54 (100%) | 54/54 (100%) | 54/54 (100%) | 54/54 (100%) |
| Ceftazidime | 92/93 (98.9%) | 91/93 (97.8%) | 92/93 (98.9%) | 91/93 (97.8%) |
| Ceftazidime-Avibactam | 47/47 (100%) | 43/47 (91.5%) | 47/47 (100%) | 43/47 (91.5%) |
| Eravacycline | 103/103 (100%) | 99/103 (96.1%) | 103/103 (100%) | 99/103 (96.1%) |
| Gentamicin | 116/121 (95.9%) | 116/121 (95.9%) | 116/121 (95.9%) | 116/121 (95.9%) |
| Imipenem-Relebactam | 72/76 (94.7%) | 72/76 (94.7%) | 72/76 (94.7%) | 72/76 (94.7%) |
| Levofloxacin | 179/181 (98.9%) | 174/181 (96.1%) | 179/181 (98.9%) | 174/181 (96.1%) |
| Meropenem | 57/58 (98.3%) | 56/58 (96.6%) | 57/58 (98.3%) | 56/58 (96.6%) |
| Meropenem-Vaborbactam | 45/47 (95.7%) | 43/47 (91.5%) | 45/47 (95.7%) | 43/47 (91.5%) |
| Piperacillin-Tazobactam | 54/56 (96.4%) | 54/56 (96.4%) | 54/56 (96.4%) | 54/56 (96.4%) |
| Trimethoprim-Sulfamethoxazole | 62/65 (95.4%) | 61/65 (93.8%) | 62/65 (95.4%) | 61/65 (93.8%) |

# Clinical Studies

The following table gives the antimicrobial-organism combinations tested and includes the reporting range and breakpoints of each combination.

| Antimicrobial | Abbreviation | Targeted Organism | Reporting Range | Breakpoints | Antimicrobial | Organism Group | Total<br>Tested | # in EA | % EA | # in CA | % CA | # R | # VMJ | # MAJ | # MIN |
|-----------------------------------|------------------------|----------------------------------------------------------------|------------------------|----------------------------------------------------------------------------------|-----------------------------|---------------------------------|-----------------|---------|------|---------|------|-----|-------|-------|-------|
| Amikacin | AMK | <i>Pseudomonas</i><br><i>aeruginosa</i> | ≤0.12 to ≥256<br>µg/mL | ≤16 / 32 / ≥64 | Amikacin | Pseudomonas aeruginosa | 165 | 150 | 90.9 | 162 | 98.2 | 7 | 0 | 0 | 3 |
| Amoxicillin-<br>Clavulanate | AMC | Enterobacterales | ≤0.5 to ≥128<br>µg/mL | ≤8 / 16 / ≥32 | Amoxicillin-<br>Clavulanate | Enterobacterales | 457 | 437 | 95.6 | 423 | 92.6 | 110 | 1 | 2 | 31 |
| Ampicillin | AMP | Enterobacterales | ≤0.25 to ≥128<br>µg/mL | ≤8 / 16 / ≥32 | Ampicillin | Enterobacterales | 254 | 241 | 94.9 | 251 | 98.8 | 118 | 1 | 1 | 1 |
| Ampicillin-<br>Sulbactam | SAM | <i>Acinetobacter<br/>baumannii</i> complex<br>Enterobacterales | ≤0.5 to ≥128<br>µg/mL | ≤8 / 16 / ≥32 | Ampicillin-<br>Sulbactam | Acinetobacter baumannii complex | 123 | 113 | 91.9 | 114 | 92.7 | 52 | 1 | 2 | 6 |
| Aztreonam | ATM | Enterobacterales | ≤0.03 to ≥128<br>µg/mL | ≤4 / 8 / ≥16 | Aztreonam | Enterobacterales | 183 | 179 | 97.8 | 178 | 97.3 | 46 | 0 | 0 | 5 |
| Cefazolin | CFZ | Enterobacterales | ≤0.12 to ≥128<br>µg/mL | ≤1 / 2 / ≥4 | Cefazolin | Enterobacterales | 358 | 339 | 94.7 | 287 | 80.2 | 215 | 1 | 0 | 70 |
| Cefepime | FEP | Enterobacterales | ≤0.25 to ≥128<br>µg/mL | ≤2 / 4-8 / ≥16 | Cefepime | Enterobacterales | 882 | 833 | 94.4 | 845 | 95.8 | 127 | 2 | 10 | 25 |
| Cefoxitin | FOX | Enterobacterales | ≤1 to ≥128 µg/mL | ≤4 / 8 / ≥16 | Cefoxitin | Enterobacterales | 583 | 538 | 92.3 | 461 | 79.1 | 103 | 3 | 8 | 111 |
| Ceftazidime | CAZ | Enterobacterales | ≤0.25 to ≥64<br>µg/mL | ≤4 / 8 / ≥16 | Ceftazidime | Enterobacterales | 787 | 752 | 95.6 | 759 | 96.4 | 208 | 1 | 1 | 26 |
| Antimicrobial | Abbreviation | Targeted Organism | Reporting Range | Breakpoints | Ceftazidime-<br>Avibactam | Enterobacterales | 815 | 793 | 97.3 | 810 | 99.4 | 32 | 0 | 5 | 0 |
| Ceftazidime-<br>Avibactam | CZA | Enterobacterales<br><i>Pseudomonas<br/>aeruginosa</i> | ≤0.12 to ≥64<br>μg/mL | ≤8 / ≥16 | Ceftriaxone | Pseudomonas aeruginosa | 163 | 151 | 92.6 | 158 | 96.9 | 10 | 0 | 2 | 0 |
| Ceftriaxone | CRO | Enterobacterales | ≤0.25 to ≥32<br>μg/mL | ≤1 / 2 / ≥4 | Ceftriaxone | Enterobacterales | 668 | 650 | 97.3 | 657 | 98.4 | 188 | 1 | 4 | 3 |
| Ciprofloxacin | CIP | Enterobacterales<br><i>Pseudomonas<br/>aeruginosa</i> | ≤0.03 to ≥16<br>μg/mL | Enterobacterales:<br>≤0.25 / 0.5 / ≥1<br><i>P. aeruginosa</i> :<br>≤0.5 / 1 / ≥2 | Ciprofloxacin | Enterobacterales | 818 | 791 | 96.7 | 787 | 96.2 | 177 | 2 | 3 | 26 |
| Eravacycline | ERV | Enterobacterales | ≤0.016 to ≥4<br>μg/mL | ≤0.5 / - | | Pseudomonas aeruginosa | 169 | 162 | 95.9 | 160 | 94.7 | 33 | 0 | 4 | 5 |
| Ertapenem | ETP | Enterobacterales | ≤0.03 to ≥16<br>μg/mL | ≤0.5 / 1 / ≥2 | Eravacycline | Enterobacterales | 487 | 478 | 98.2 | 480 | 98.6 | 54 | 2 | 1 | 0 |
| Gentamicin | GEN | Enterobacterales | ≤0.06 to ≥64<br>μg/mL | ≤4 / 8 / ≥16 | Ertapenem | Enterobacterales | 882 | 849 | 96.3 | 868 | 98.4 | 101 | 0 | 8 | 6 |
| Imipenem-<br>Relebactam | IMR | Enterobacterales<br><i>Pseudomonas<br/>aeruginosa</i> | ≤0.03 to ≥128<br>μg/mL | Enterobacterales:<br>≤1 / 2 / ≥4<br><i>P. aeruginosa</i> :<br>≤2 / 4 / ≥8 | Gentamicin | Enterobacterales | 741 | 713 | 96.2 | 733 | 98.9 | 113 | 1 | 1 | 6 |
| Levofloxacin | LVX | Enterobacterales | ≤0.06 to ≥32<br>μg/mL | ≤0.5 / 1 / ≥2 | | Pseudomonas aeruginosa | 218 | 211 | 96.8 | 212 | 97.2 | 15 | 0 | 0 | 6 |
| Meropenem | MEM | Enterobacterales<br><i>Pseudomonas<br/>aeruginosa</i> | ≤0.12 to ≥64<br>μg/mL | Enterobacterales:<br>≤1 / 2 / ≥4<br><i>P. aeruginosa</i> :<br>≤2 / 4 / ≥8 | Imipenem-<br>Relebactam | Enterobacterales | 471 | 440 | 93.4 | 459 | 97.5 | 33 | 0 | 3 | 9 |
| Meropenem-<br>Vaborbactam | MEV | Enterobacterales | ≤0.06 to ≥64<br>μg/mL | ≤4 / 8 / ≥16 | | Pseudomonas aeruginosa | 165 | 159 | 96.4 | 162 | 98.2 | 6 | 0 | 0 | 3 |
| Minocycline | MIN | Enterobacterales | ≤0.25 to ≥64<br>μg/mL | ≤4 / 8 / ≥16 | Levofloxacin | Enterobacterales | 784 | 753 | 96 | 744 | 94.9 | 161 | 1 | 6 | 33 |
| Piperacillin-<br>Tazobactam | TZP | Enterobacterales | ≤0.25 to ≥512<br>μg/mL | ≤16 / 32-64 / ≥128 | Meropenem | Enterobacterales | 833 | 801 | 96.2 | 816 | 98 | 83 | 1 | 12 | 4 |
| Tobramycin | TOB | <i>Pseudomonas<br/>aeruginosa</i> | ≤0.12 to ≥128<br>μg/mL | ≤4 / 8 / ≥16 | | Pseudomonas aeruginosa | 175 | 163 | 93.1 | 168 | 96 | 38 | 0 | 0 | 7 |
| Trimethoprim-<br>Sulfamethoxazole | SXT | Enterobacterales | ≤0.12 to ≥32<br>μg/mL | ≤2 / ≥4 | Meropenem-<br>Vaborbactam | Enterobacterales | 760 | 727 | 95.7 | 752 | 98.9 | 41 | 1 | 1 | 6 |
| Minocycline | Enterobacterales | 391 | 353 | 90.3 | 372 | 95.1 | 37 | 1 | 3 | 16 | | | | | |
| Piperacillin-<br>Tazobactam | Enterobacterales | 699 | 644 | 92.1 | 680 | 97.3 | 108 | 2 | 3 | 13 | | | | | |
| Tobramycin | Pseudomonas aeruginosa | 166 | 155 | 93.4 | 162 | 97.6 | 14 | 0 | 1 | 3 | | | | | |
| Trimethoprim-<br>Sulfamethoxazole | Enterobacterales | 449 | 435 | 96.9 | 442 | 98.4 | 142 | 4 | 1 | 0 | | | | | |

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Clinical performance testing on the Selux AST System was performed at three test sites. Contemporary and frozen clinical isolates from diverse geographic locations across the US were evaluated for performance as were banked challenge isolates, which were selected for their resistance profiles. A total of 1401 clinical (426 contemporary and 975 stock) and 222 challenge isolates from 12 Enterobacterales species, Acinetobacter baumannii complex, and Pseudomonas aeruginosa were tested to evaluate the Selux AST System performance for 24 antimicrobials. Depending on the spectrum of activity, breakpoints, and the claimed organisms (species/group)

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for each antimicrobial on the panel, the number of datapoints for the various antimicrobialorganisms tested varied and ranged from 165 (e.g. P. aeruginosa/Imipenem-Relebactam) to 977 (e.g. Enterobacterales/Ertapenem).

Selux AST System performance was determined by comparing Selux AST System results with triplicate broth microdilution results performed at an independent reference laboratory. The Selux AST System meets performance criteria for each indication and is given in the following table, where performance is summarized by reporting group. Additionally, QC testing was performed every day testing was performed at each site and met the 95% performance criteria for all antimicrobials.

# Conclusion

Based on our studies and testing, the Selux AST System was determined to be substantially equivalent to the predicate device (K190905).