PBC Separator with Selux AST System

K244044 · Selux Diagnostics, Inc. · QZX · Mar 28, 2025 · Microbiology

Device Facts

• Record ID: K244044
• Device Name: PBC Separator with Selux AST System
• Applicant: Selux Diagnostics, Inc.
• Product Code: QZX · Microbiology
• Decision Date: Mar 28, 2025
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.1650
• 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.

Device Story

The PBC Separator is an automated instrument for preparing bacterial inocula from positive blood culture bottles. It processes samples from continuous monitoring blood culture systems (e.g., BACTEC, BacT/ALERT) using lysis, centrifugation, and sequential optical density measurements to achieve a tuned McFarland-equivalent suspension. The device is used in clinical laboratories by technicians. The resulting inoculum is transferred to the Selux AST System, which incubates samples and quantifies microbial growth in a 384-well panel to determine minimum inhibitory concentrations (MICs). The system requires manual or LIS-downloaded organism identification to interpret susceptibility results. The device enables faster AST results (under 7 hours) compared to traditional methods, aiding clinicians in selecting appropriate antimicrobial therapy for patients with bloodstream infections.

Clinical Evidence

Clinical performance was evaluated using 247 clinical (64 fresh, 183 seeded) and 75 challenge isolates across three sites. Performance was compared to broth microdilution reference methods. Essential Agreement (EA) and Categorical Agreement (CA) were calculated for various antimicrobial-organism combinations. Results showed high EA (mostly >94%) and CA (mostly >96%) across tested gram-positive organisms (Enterococci, S. aureus). Reproducibility studies (intra- and inter-site) demonstrated ≥94% agreement. Interfering substances (endogenous/exogenous) showed minimal impact on performance.

Technological Characteristics

Automated sample preparation instrument using lysis, centrifugation, and on-board spectrophotometry for optical density measurement. 384-well panel format for AST. Connectivity: Networked to site workstation. Software: Embedded firmware (v70.0) and Selux AST System software (v1.12). Sterilization: Not applicable (consumables). Standards: IEC 60601-1-2, ANSI UL 61010-1, IEC 62304, ISO 14971.

Indications for Use

Indicated for automated inoculum preparation from positive blood culture samples (monomicrobial, gram-negative rods or gram-positive cocci) for use with the Selux AST System for quantitative antimicrobial susceptibility testing. Requires organism identification for result interpretation.

Regulatory Classification

Identification

A cellular analysis system for multiplexed antimicrobial susceptibility testing is a multiplex qualitative and/or quantitative in vitro diagnostic device intended for the identification and determination of the antimicrobial susceptibility results of organisms detected in samples from patients with suspected microbial infections. This device is intended to aid in the determination of antimicrobial susceptibility or resistance when used in conjunction with other laboratory findings.

Special Controls

*Classification.* Class II (special controls). The special controls for this device are:(1) Design verification and validation must include: (i) Detailed device description documentation, including the device components, ancillary reagents required but not provided, a detailed explanation of the methodology, including primer/probe sequence, design, rationale for sequence selection, and details of the antimicrobial agents, as applicable. (ii) Detailed documentation from the following analytical and clinical performance studies: limit of detection, inclusivity, precision, reproducibility, interference, cross-reactivity, carryover, and cross-contamination, quality control and additional studies, as applicable to specimen type and assay intended use. (iii) Detailed documentation from an appropriate clinical study. The study, performed on a study population consistent with the intended use population, must compare the device performance to results obtained from well-accepted reference methods. (iv) Detailed documentation for device software, including software applications and hardware-based devices that incorporate software. (2) The labeling required under § 809.10(b) of this chapter must include: (i) Limitations and protocols regarding the need for correlation of results by standard laboratory procedures, as applicable. (ii) A detailed explanation of the interpretation of results and acceptance criteria. (iii) A detailed explanation of the principles of operation and procedures for assay performance and troubleshooting.

Predicate Devices

• PBC Separator with Selux AST System (K223493)

Submission Summary (Full Text)

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Image /page/0/Picture/0 description: The image shows the logo of the U.S. Food and Drug Administration (FDA). On the left is the Department of Health and Human Services logo. To the right of that is the FDA logo, which is a blue square with the letters "FDA" in white. To the right of the blue square is the text "U.S. FOOD & DRUG ADMINISTRATION" in blue.

March 28, 2025

Selux Diagnostics, Inc. Carrene Plummer VP, Regulatory and Quality 56 Roland Street, Suite 206 Charlestown, Massachusetts 02129

Re: K244044

Trade/Device Name: PBC Separator with Selux AST System Regulation Number: 21 CFR 866.1650 Regulation Name: A Cellular Analysis System For Multiplexed Antimicrobial Susceptibility Regulatory Class: Class II Product Code: QZX, LON, LTT, LTW Dated: December 30, 2024 Received: December 30, 2024

Dear Carrene Plummer:

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 (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 available 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.

Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device"

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(https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).

Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30. Design controls; 21 CFR 820.90. Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the OS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).

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 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 Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safetyreporting-combination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.

All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rue"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advicecomprehensive-regulatory-assistance/unique-device-identification-system-udi-system.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 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).

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Sincerely,

# Courtney E. Chandler -S for

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) K244044

#### Device Name PBC Separator with Selux AST System

#### Indications for Use (Describe)

The PBC Separator with Selux AST System is an automated inoculum preparation system that uses lysis, centrifygation and sequential optical density measurements to generate a McFarland-equivalent suspension from positive blood culture samples that can be used for quantitative in vitro antimicrobial susceptibility testing by the Selux AST System. Samples are processed directly from blood culture samples identified as positive by a continuous monitoring blood culture system. Samples should be confirmed as monomicrobial, gram negative rods or gram positive cocci by Gram stain. Organism identification is required for AST result interpretation and reporting, per the Selux AST System Instructions for Use.

Inoculum preparation by the PBC Separator was evaluated for use with the Selux AST System and the Selux AST Gram Negative Panel. Performance was demonstrated for the antimicrobial agents and organisms identified below:

• Amikacin: Acinetobacter baumannii complex, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa

· Amoxicillin-Clavulanate: Escherichia coli, Klebsiella species (including K. oxytoca, K. pneumoniae), Proteus mirabilis, Proteus vulgaris

· Ampicillin: Escherichia coli, Proteus mirabilis

· Ampicillin-Sulbactam: Acinetobacter baumannii complex, Citrobacter koseri, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis

• 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, Pseudomonas aeruginosa

• Ceftazidime: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa

· Ceftazidime-Avibactam: Citrobacter freundii complex, Citrobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Serratia marcescens, Pseudomonas aeruginosa

· Ceftriaxone: Citrobacter freundii complex, Citrobacter cloacae complex, Escherichia coli,

Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Proteus mirabilis, Serratia marcescens

• Ciprofloxacin: Citrobacter freundii complex, Citrobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Serratia marcescens, Pseudomonas aeruginosa

• Ertapenem: Citrobacter freundii complex, Citrobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Morganii, Proteus mirabilis, Proteus vulgaris, Serratia marcescens

• Gentamicin: Citrobacter freundii complex, Citrobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Serratia marcescens, Pseudomonas aeruginosa

· Imipenem: Acinetobacter baumannii complex, Escherichia coli, Klebsiella pneumoniae

· Meropenem: Acinetobacter baumannii complex, Citrobacter koser, Enterobacter cloacae complex, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Morganii, Proteus mirabilis, Proteus vulgaris, Serratia marcescens, Pseudomonas aeruginosa

· Minocycline: Acinetobacter baumannii complex, Escherichia coli, Klebsiella pneumoniae

• Piperacillin-Tazobactam: Acinetobacter baumannii complex, Citrobacter koseri, Escherichia coli, Klebsiella pneumoniae, Morganella morganii, Proteus vulgaris, Serratia marcescens, Pseudomonas aeruginosa

• Tobramycin: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa

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Inoculum preparation by the PBC Separator was evaluated for use with the Selux AST System and the Selux AST Gram Positive Panel. Performance was demonstrated for the antimicrobial agents and organisms identified below:

- Ampicillin: Enterococcus faecalis, Enterococcus faecium
- Ceftaroline: Staphylococcus aureus
- Daptomycin: Enterococcus faecalis, Enterococcus faecium, Staphylococcus aureus
- · Linezolid: Enterococcus faecalis, Enterococcus faecium, Staphylococcus aureus
- Oxacillin: Staphylococcus aureus
- Vancomycin: Enterococcus faecalis, Enterococcus faecium, Staphylococcus aureus

The PBC Separator with Selux AST System Gram Positive Panel is a qualitative test for the following antimicrobial agents with the specific target organisms identified below:

- · Cefoxitin Screen to predict mecA-mediated oxacillin resistance: Staphylococcus aureus
Susceptibility test results are intended to be used in conjunction with other clinical and laboratory findings. Standard laboratory protocols for processing positive blood cultures should be followed to ensure availability of isolates for supplemental testing as needed. Additionally, subculture of positive is necessary for the susceptibility testing of organisms present in polymicrobial samples, for testing antimicrobial agents and species not indicated for testing with the device, for epidemiologic testing, and for recovery of organisms present in microbial samples.

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

X 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 PBC Separator with Selux AST System

Date prepared: March 27, 2025

#### Submitter:

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

#### Contact:

Carrene Plummer Tel. [phone]

#### Subject Device

| Trade Name: | PBC Separator with Selux AST System |
|-----------------------|------------------------------------------------------------------------------------------------------------|
| Common Name: | Separator for GN and GP Bacteria |
| Regulation Number: | 21 CFR 866.1650 |
| Regulation Name: | Positive Blood Culture Processor For Inoculum Preparation Used for<br>Antimicrobial Susceptibility Testing |
| Regulatory Class: | Class II |
| Product Code: | QZX, LON, LTT, LTW |
| Classification Panel: | 83 (Microbiology) |

#### Predicate Device

| Trade Name: | PBC Separator with Selux AST System |
|-----------------------|---------------------------------------------------------------------------------------------------------|
| Manufacturer: | Selux Diagnotics, Inc. |
| 510(k) Reference: | K223493 |
| Common Name: | Separator for GN and GP Bacteria |
| Regulation Number: | 21 CFR 866.1650 |
| Regulation Name: | Positive Blood Culture Processor For Inoculum Preparation Used for Antimicrobial Susceptibility Testing |
| Regulatory Class: | Class II |
| Product Code: | QZX, LON, LTT, LTW |
| Classification Panel: | 83 (Microbiology) |

## Device Description

The Positive Blood Culture (PBC) Separator with Selux AST System is an automated sample preparation instrument with associated consumables that uses lysis, centrifugation, and sequential optical density measurements to prepare a tuned McFarland-equivalent inoculum from positive blood culture bottles that have rung positive on a continuous monitoring blood culture system. Inoculums containing monomicrobial, gram negative or gram positive bacteria are used for Antimicrobial Susceptibility Testing (AST) processing with the Selux AST System. The Selux AST System includes a sample prep station (i.e., AST Workbench), an Inoculator, an Analyzer, Workbench Computer, and the reagents and consumables required to perform AST testing. The PBC Separator and all Selux AST System components are connected to a site workstation, which coordinates sample processing on all instruments. The PBC Separator contains embedded software and a graphical user interface that guides users through the PBC Separator workflow. Once processing of the PBC sample is complete, the user transfers the tuned McFarland inoculum to the Selux AST System for further AST processing.

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The PBC Separator with Selux AST System can only provide AST results for monomicrobial samples. Since the PBC Separator with Selux AST System does not perform identification (ID), the monomicrobial nature of the sample under test must be confirmed by an FDA-cleared directfrom-positive blood culture ID system.

While PBC Separator processing can be performed without species-level ID, this information is required for the Selux AST System to interpret and report susceptibility results. Species ID can be performed by any appropriate method and this information can be either manually input to the Selux AST System or automatically downloaded from the laboratory information system (LIS) at any time, once the sample ID is entered into the LIS.

The PBC Separator with the Selux AST System utilizes a 384-well panel, either the Selux Gram-Negative Panel or Selux Gram-Positive Panel, that provides parallel results for the antimicrobials indicated for each sample type. The Selux AST System software masks non-indicated results. The average time-to-result for positive blood culture processed with the PBC Separator and Selux AST System is under 7 hours.

#### Principle of Operation

The PBC Separator automatically prepares a tuned bacterial inoculum directly from a blood culture bottle sample that "rang" positive on an FDA-cleared continuous monitoring blood culture system, including the Becton Dickinson BACTEC, the bioMerieux BacT/Alert 3D, and the bioMerieux Virtuo. The PBC Separator removes contaminants through repeated centrifugation-wash cycles and specific chemical lysis of mammalian cells and cell fragments. The PBC Separator utilizes an on-board spectrometer to tune the inoculum for the right cell density to perform AST.

Tuned inoculums are used with the Selux AST System. The Selux AST System 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 minimum inhibitory concentration (MIC) by comparing growth data in each well,

AST testing of PBC samples requires that the Gram type (classification) of the organism be known prior to testing on the Selux AST System as the information is necessary to select the proper AST panel to use. Organism identification (ID) is not needed to initiate testing with the Selux AST System. However, the organism ID is necessary for a result to be interpreted and reported because the MIC-determining algorithm is species-specific as is the interpretative Susceptible (S), Susceptible Dose Dependent (SDD), Intermediate (I), or Resistant (R) determination. Any FDAcleared method may be used to provide an ID including biochemical techniques, matrix-assisted laser desorption/ionization mass spectrometry, and multiplex genetic assays.

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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.

#### Indications for Use

The PBC Separator with Selux AST System is an automated inoculum preparation system that uses lysis, centrifugation and sequential optical density measurements to generate a McFarlandequivalent suspension from positive blood culture samples that can be used for quantitative in vitro antimicrobial susceptibility testing by the Selux AST System. Samples are processed directly from blood culture samples identified as positive by a continuous monitoring blood culture system. Samples should be confirmed as monomicrobial, gram negative rods or gram positive cocci by Gram stain. Organism identification is required for AST result interpretation and reporting, per the Selux AST System Instructions for Use.

Inoculum preparation by the PBC Separator was evaluated for use with the Selux AST System and the Selux AST Gram Negative Panel. Performance was demonstrated for the antimicrobial agents and organisms identified below:

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

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- . Gentamicin: Citrobacter freundii complex, Citrobacter koseri, Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Servatia marcescens, Pseudomonas aeruginosa
- Imipenem: Acinetobacter baumannii complex, Escherichia coli, Klebsiella pneumoniae ●
- Meropenem: Acinetobacter baumannii complex, Citrobacter freundii complex, Citrobacter . koseri, Enterobacter cloacae complex, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Serratia marcescens, Pseudomonas aeruginosa
- Minocycline: Acinetobacter baumannii complex, Escherichia coli, Klebsiella pneumoniae ●
- . Piperacillin-Tazobactam: Acinetobacter baumannii complex, Citrobacter koseri, Escherichia coli, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Serratia marcescens, Pseudomonas aeruginosa
- Tobramycin: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa

Inoculum preparation by the PBC Separator was evaluated for use with the Selux AST System and the Selux AST Gram Positive Panel. Performance was demonstrated for the antimicrobial agents and organisms identified below:

- Ampicillin: Enterococcus faecalis. Enterococcus faecium ●
- Ceftaroline: Staphylococcus aureus ●
- Daptomycin: Enterococcus faecalis, Enterococcus faecium, Staphylococcus aureus ●
- Linezolid: Enterococcus faecalis, Enterococcus faecium, Staphvlococcus aureus
- Oxacillin: Staphylococcus aureus ●
- Vancomycin: Enterococcus faecalis, Enterococcus faecium, Staphylococcus aureus

The PBC Separator with Selux AST System Gram Positive Panel is a qualitative test for the following antimicrobial agents with the specific target organisms identified below:

- Cefoxitin Screen to predict mecA-mediated oxacillin resistance: Staphylococcus ● aureus
Susceptibility test results are intended to be used in conjunction with other clinical and laboratory findings. Standard laboratory protocols for processing positive blood cultures should be followed to ensure availability of isolates for supplemental testing as needed. Additionally, subculture of positive blood culture is necessary for the susceptibility testing of organisms present in polymicrobial samples, for testing antimicrobial agents and indicated for testing with the device, for epidemiologic testing, and for recovery of organisms present in microbial samples.

## Comparison of Technological Characteristics with the Predicate and Reference Devices

The technological characteristics of the PBC Separator with Selux AST System for Gram-positive bacteria are substantially equivalent to the primary predicate device, the PBC Separator with Selux AST System for Gram-negative bacteria (K223493), in terms of intended use, application, user population, basic design, performance, and labeling.

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| Device & Predicate<br>Devices: | K244044<br>Candidate Device | K223493<br>Predicate Device |
|-----------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Device Trade Name | PBC Separator with Selux AST<br>System - GN and GP | PBC Separator with Selux AST<br>System - GN |
| Device Characteristics | | |
| Indication for Use | The PBC Separator with Selux AST<br>System is an automated inoculum<br>preparation system that uses lysis,<br>centrifugation and sequential optical<br>density measurements to generate a<br>McFarland-equivalent suspension<br>from positive blood culture samples<br>that can be used for quantitative in<br>vitro antimicrobial susceptibility<br>testing by the Selux AST System.<br>Samples are processed directly from<br>blood culture samples identified as<br>positive by a continuous monitoring<br>blood culture system. Samples<br>should be confirmed as<br>monomicrobial, gram negative rods<br>or gram positive cocci by Gram<br>stain. Organism identification is<br>required for AST result<br>interpretation and reporting, per the<br>Selux AST System Instructions for<br>Use. | The PBC Separator with the Selux AST<br>System is an automated inoculum<br>preparation system that uses lysis,<br>centrifugation and sequential optical<br>density measurements to generate a<br>McFarland-equivalent suspension from<br>positive blood culture samples that can<br>be used for quantitative in vitro<br>antimicrobial susceptibility testing by<br>the Selux AST System. Samples are<br>processed directly from blood culture<br>samples identified as positive by a<br>continuous monitoring blood culture<br>system. Samples should be confirmed as<br>monomicrobial, gram negative rods by<br>Gram stain. Organism identification is<br>required for AST result interpretation<br>and reporting, per the Selux AST<br>System instructions for use. |
| Source of<br>Microorganisms | Bacteria from positive blood cultures | Same |
| Device & Predicate<br>Devices: | K244044<br>Candidate Device | K223493<br>Predicate Device |
| Indicated<br>Antimicrobial/Organism<br>Combinations | <b>Gram-Negative Organisms:</b><br><b>Amikacin:</b> Acinetobacter baumannii<br>complex, Escherichia coli,<br>Klebsiella pneumoniae,<br>Pseudomonas aeruginosa | <b>Gram-Negative Organisms:</b><br><b>Amikacin:</b> Acinetobacter baumannii<br>complex, Escherichia coli, Klebsiella<br>pneumoniae, Pseudomonas aeruginosa |
| | <b>Amoxicillin-Clavulanate:</b><br>Escherichia coli, Klebsiella species<br>(including K. oxytoca, K.<br>pneumoniae), Proteus mirabilis,<br>Proteus vulgaris | <b>Amoxicillin-Clavulanate:</b> Escherichia<br>coli, Klebsiella species (including K.<br>oxytoca, K. pneumoniae), Proteus<br>mirabilis, Proteus vulgaris |
| | <b>Ampicillin:</b> Escherichia coli,<br>Proteus mirabilis | <b>Ampicillin:</b> Escherichia coli, Proteus<br>mirabilis |
| | <b>Ampicillin-Sulbactam:</b><br>Acinetobacter baumannii<br>complex, Citrobacter koseri,<br>Escherichia coli, Klebsiella<br>pneumoniae, Proteus mirabilis | <b>Ampicillin-Sulbactam:</b><br>Acinetobacter baumannii complex,<br>Citrobacter koseri, Escherichia<br>coli, Klebsiella pneumoniae,<br>Proteus mirabilis |
| | <b>Cefazolin:</b> Escherichia coli,<br>Klebsiella pneumoniae | <b>Cefazolin:</b> Escherichia coli,<br>Klebsiella pneumoniae |
| | <b>Cefepime:</b> Citrobacter freundii<br>complex, Citrobacter koseri,<br>Enterobacter cloacae complex,<br>Escherichia coli, Klebsiella<br>aerogenes, Klebsiella oxytoca,<br>Klebsiella pneumoniae,<br>Morganella morganii, Proteus<br>mirabilis, Proteus vulgaris,<br>Serratia marcescens,<br>Pseudomonas aeruginosa | <b>Cefepime:</b> Citrobacter freundii<br>complex, Citrobacter koseri,<br>Enterobacter cloacae complex,<br>Escherichia coli, Klebsiella<br>aerogenes, Klebsiella oxytoca,<br>Klebsiella pneumoniae,<br>Morganella morganii, Proteus<br>mirabilis, Proteus vulgaris,<br>Serratia marcescens, Pseudomonas<br>aeruginosa |
| | <b>Ceftazidime:</b> Escherichia coli,<br>Klebsiella pneumoniae,<br>Pseudomonas aeruginosa | <b>Ceftazidime:</b> Escherichia coli,<br>Klebsiella pneumoniae,<br>Pseudomonas aeruginosa |
| | <b>Ceftazidime-Avibactam:</b><br>Citrobacter freundii complex,<br>Citrobacter koseri, Enterobacter<br>cloacae complex, Escherichia<br>coli, Klebsiella aerogenes,<br>Klebsiella oxytoca, Klebsiella<br>pneumoniae, Morganella<br>morganii, Proteus mirabilis,<br>Proteus vulgaris, Serratia<br>marcescens, Pseudomonas<br>aeruginosa | <b>Ceftazidime-Avibactam:</b><br>Citrobacter freundii complex,<br>Citrobacter koseri, Enterobacter<br>cloacae complex, Escherichia coli,<br>Klebsiella aerogenes, Klebsiella<br>oxytoca, Klebsiella pneumoniae,<br>Morganella morganii, Proteus<br>mirabilis, Proteus vulgaris,<br>Serratia marcescens, Pseudomonas<br>aeruginosa |
| | <b>Ceftriaxone:</b> Citrobacter<br>freundii complex, Citrobacter<br>koseri, Enterobacter cloacae | <b>Ceftriaxone:</b> Citrobacter freundii<br>complex, Citrobacter koseri,<br>Enterobacter cloacae complex,<br>Escherichia coli, Klebsiella<br>aerogenes, Klebsiella oxytoca, |
| Device & Predicate<br>Devices: | K244044<br>Candidate Device | K223493<br>Predicate Device |
| | complex, Escherichia coli, | Klebsiella pneumoniae, Proteus |
| | Klebsiella aerogenes, Klebsiella | mirabilis, Serratia marcescens |
| | oxytoca, Klebsiella pneumoniae, | <b>Ciprofloxacin:</b> Citrobacter |
| | Proteus mirabilis, Serratia | freundii complex, Citrobacter |
| | marcescens | koseri, Enterobacter cloacae |
| | <b>Ciprofloxacin:</b> Citrobacter | complex, Escherichia coli, |
| | freundii complex, Citrobacter | Klebsiella aerogenes, Klebsiella |
| | koseri, Enterobacter cloacae | oxytoca, Klebsiella pneumoniae, |
| | complex, Escherichia coli, | Morganella morganii, Proteus |
| | Klebsiella aerogenes, Klebsiella | mirabilis, Proteus vulgaris, |
| | oxytoca, Klebsiella pneumoniae, | Serratia marcescens, Pseudomonas |
| | Morganella morganii, Proteus | aeruginosa |
| | mirabilis, Proteus vulgaris, | <b>Ertapenem:</b> Citrobacter freundii |
| | Serratia marcescens, | complex, Citrobacter koseri, |
| | Pseudomonas aeruginosa | Enterobacter cloacae complex, |
| | <b>Ertapenem:</b> Citrobacter freundii…