Predicate Devices

Reference Devices

Not Found

AI/ML (Artificial Intelligence / Machine Learning)

No
The description focuses on automated sample preparation using physical and optical methods (lysis, centrifugation, optical density measurements, spectrometer) and standard AST principles (broth microdilution, MIC determination). There is no mention of AI or ML algorithms for analysis, interpretation, or process control.

Therapeutic

No
This device is for in vitro diagnostic (IVD) use, specifically for preparing inoculum for antimicrobial susceptibility testing, which helps determine the effectiveness of antimicrobials. It does not directly treat or diagnose a disease.

Diagnostic

Yes

Explanation: The device prepares samples for antimicrobial susceptibility testing (AST), which provides information on how effective different antimicrobial agents are against specific microorganisms. This information is critical for guiding treatment decisions, making it a diagnostic device as it determines the nature of a disease state (e.g., susceptibility to antibiotics).

SaMD (Software as a Medical Device)

No

The device description explicitly states that the PBC Separator with Selux AST System is an "automated sample preparation instrument with associated consumables" and includes components like a "sample prep station (i.e., AST Workbench), an Inoculator, an Analyzer, Workbench Computer". This indicates the presence of significant hardware components beyond just software.

IVD (In Vitro Diagnostic)

Yes, this device is an IVD (In Vitro Diagnostic).

Here's why:

Intended Use: The "Intended Use / Indications for Use" section explicitly states that the system is used for "quantitative in vitro antimicrobial susceptibility testing". In vitro diagnostic devices are intended for use in the collection, preparation, and examination of specimens taken from the human body for the purpose of diagnosing disease or other conditions, including determining the state of health, in order to cure, mitigate, treat, or prevent disease or its sequelae. Antimicrobial susceptibility testing falls under this definition as it provides information crucial for treating infections.
Device Description: The description details how the device processes biological samples (positive blood culture samples) to prepare them for testing.
Principle of Operation: The principle of operation describes how the device interacts with the biological sample to achieve the intended result (preparing a tuned inoculum for AST).
Clinical Studies: The document describes clinical performance testing using human blood culture samples to evaluate the device's performance in a clinical setting.
Key Metrics: The performance is evaluated using metrics like Essential Agreement (EA), Category Agreement (CA), Major Errors (MAJ), Minor Errors (MIN), and Very Major Errors (VMJ), which are standard metrics for evaluating the performance of IVD devices, particularly those related to antimicrobial susceptibility testing.
Predicate Device: The mention of a predicate device (K223493; PBC Separator with Selux AST System - GN) further indicates that this device is being submitted for regulatory review as an IVD, as predicate devices are used for comparison in the regulatory process for new IVDs.

All these points align with the definition and characteristics of an In Vitro Diagnostic device.

PCCP (Predetermined Change Control Plan) Authorized

N/A

Overview

Intended Use / 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 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

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.

Product codes (comma separated list FDA assigned to the subject device)

QZX, LON, LTT, LTW

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.

Mentions image processing

Not Found

Mentions AI, DNN, or ML

Not Found

Input Imaging Modality

Not Found

Anatomical Site

Not Found

Indicated Patient Age Range

Not Found

Intended User / Care Setting

Not Found

Description of the training set, sample size, data source, and annotation protocol

Not Found

Description of the test set, sample size, data source, and annotation protocol

A total of 247 clinical (64 fresh and 183 seeded) and 75 challenge isolates from 2 Enterococci species and Staphylococcus aureus were tested to evaluate the PBC Separator performance for 7 antimicrobials with the Selux AST System. Depending on the spectrum of activity, breakpoints, and the claimed organisms (species/group) for each antimicrobial on the panel, the number of datapoints for the various antimicrobial-organisms tested varied and ranged from 100 (e.g., E. faecium/Daptomycin) to 211 (e.g., Enterococci/Linezolid).

Summary of Performance Studies (study type, sample size, AUC, MRMC, standalone performance, key results)

Reproducibility

PBC Separator with Selux AST System intra- and inter-site reproducibility were evaluated by testing a minimum of 5 samples for each of 9 representative antimicrobials at each of three test sites (2 external, 1 internal). Each sample comprised an isolate that was seeded at approximately 10-10.000 CFU into a blood culture bottle with approximately 10 mL of fresh human blood from a healthy donor and then loaded into an FDA-cleared continuous monitoring blood culture system (BD BACTEC or bioMerieux BacT/ALERT VIRTUO) until positive growth was detected. The positive blood culture bottle was then removed and processed using the PBC Separator with Selux AST System. Each sample was tested in triplicate using three different inoculums prepared by the PBC Separator on each of three days it was tested at each site. There is thus a minimum of 3 × 3 = 9 results per sample and 9 × 5 = 45 results per antimicrobial at a single site. The acceptance criteria were defined as ≥95% best-case reproducibility and a ≥89% worst-case reproducibility for inter- and intra-site reproducibility.

The intra-site reproducibility was ≥ 97% for best- and worst-case.
The inter-site reproducibility was ≥ 95% for best-case and > 94% for worst-case.

Post-Positivity Sample Stability Study

The amount of time between the registration of positive growth for a sample and the initiation of processing with the PBC Separator was evaluated. Selux AST System MIC results from samples run with the PBC Separator 16 and 18 hours after registering positive growth in a continuous monitoring blood culture system were compared with t = 0 hr control MIC results from samples processed on the PBC Separator immediately after registering positive growth. At least three replicates of one species from each indicated antimicrobial/organism reporting group were tested per drug per timepoint. The total EA for all results at the 16-hour timepoints compared with the 0-hour timepoint was 100.0% (30/30 results in EA).

Blood Culture Bottle Compatibility Study

Eleven types of blood culture bottles incubated in BD BACTEC and bioMérieux BacT/ALERT VIRTUO continuous monitoring blood culture systems were evaluated with the PBC Separator with Selux AST System. Bacterial samples were seeded at clinically relevant concentrations into the blood culture bottles with the manufacturer recommended volume of human blood. Seeded bottles were loaded into a continuous monitoring blood culture system and incubated until positivity. Positive blood culture samples were then processed with the PBC Separator with Selux AST System. One isolate from each reporting group was tested with three replicates per bottle type and evaluated with all claimed antimicrobials. Aerobic bottles were seeded with E. faecalis and S. aureus.

Selux AST System MIC results from tested bottle types showed >89.9% essential agreement to the reference method. Across all aerobic bottle types there was 99.4% EA (179/180 results in EA) and each aerobic bottle type had EA of ≥96.7%. Across all anaerobic bottle types there was 99.3% EA (149/150 results in EA) and each anaerobic bottle type had EA of ≥96.7%. Cefoxitin Screen was considered separately since results are either positive and showed 100% agreement with expected results except for Cefoxitin-Staphylococci, which demonstrated 66.7% (2/3) out-ofagreement results in BD BACTEC Aerobic Plus bottles.

Interfering Substances Testing

The effect of the presence of endogenous and exogenous interferents that may be present in a blood culture was evaluated on the PBC Separator with Selux AST System for gram-positive organisms. Studies were performed by seeding the two most common gram-positive species isolated from blood cultures, E. faecalis and S. aureus, at clinically relevant concentrations into non-resin blood culture bottles with the manufacturer recommended volume of human blood. Potential interferents were seeded into the blood culture bottles at the time of bacterial seeding and prior to incubation in the blood culture system. Control samples to which no interferents were added were processed in parallel. Seeded bottles were loaded into a continuous monitoring blood culture system and incubated until positivity. Positive blood culture samples were then processed with the PBC Separator with Selux AST System.

Endogenous interferents evaluated: red blood cells (RBCs), white blood cells (WBCs), platelets, triglycerides, gamma globulin, and conjugated and unconjugated bilirubin.
Exogenous interferents evaluated: cefpodoxime, ciprofloxacin, penicillin, and gentamicin.

The PBC Separator with Selux AST System MIC results showed >89.9% EA for every interferent tested when compared with PBC Separator with Selux AST System results for the same organism run in a control condition (no interferent). Cefoxitin Screen was considered separately since results are either positive or negative. No interference was observed, i.e., results exactly matched the control result for all endogenous and exogenous interferents.

Clinical Studies

Clinical performance testing with the PBC Separator with Selux AST System for gram-positive organisms was performed at three test sites using fresh positive blood culture samples left over from routine clinical care and seeded samples. Seeded samples were prepared using banked frozen isolates seeded at 10-10,000 CFU into blood culture bottles together with approximately 10 mL of fresh human blood from a healthy donor and then loaded into an FDA-cleared continuous monitoring blood culture system until positive growth was detected. Positive blood bottles were tested with the PBC Separator and Selux AST System. Fresh positive blood culture and seeded samples were collected from clinical sites to represent geographic diversity across the continental U.S. A total of 247 clinical (64 fresh and 183 seeded) and 75 challenge isolates from 2 Enterococci species and Staphylococcus aureus were tested to evaluate the PBC Separator performance for 7 antimicrobials with the Selux AST System. Depending on the spectrum of activity, breakpoints, and the claimed organisms (species/group) for each antimicrobial on the panel, the number of datapoints for the various antimicrobial-organisms tested varied and ranged from 100 (e.g., E. faecium/Daptomycin) to 211 (e.g., Enterococci/Linezolid).

PBC Separator with Selux AST System performance for gram-positive organisms was determined by comparing Selux AST System results from PBC Separator-prepared inoculums to triplicate broth microdilution results performed at an independent reference laboratory. The PBC Separator with the Selux AST System meets performance criteria for each indication and is given in the table below, where performance is summarized by drug and reporting group. Additionally, QC testing was performed every day testing was performed at each site and met the 95% performance criteria for all antimicrobials.

Key Metrics (Sensitivity, Specificity, PPV, NPV, etc.)

Clinical Studies

Antimicrobial	Organism Group	Total Tested	# in EA	% EA	# in CA	% CA	# R	# S	# MAJ	# MIN
AMP	Enterococci	210	209	99.5	210	100	92	118	0	-
CPT	Staphylococci	111	110	99.1	105	94.6	0	109	0	6
DAP	Enterococcus faecalis	103	100	97.1	100	97.1	0	103	2	1
DAP	Enterococcus faecium	100	94	94	98	98	0	100	2	-
DAP	Staphylococci	108	108	100	108	100	0	108	0	-
FOX SCN	Staphylococci	109	-	-	109	100	54	55	0	-
LNZ	Enterococci	211	210	99.5	210	99.5	0	211	1	0
LNZ	Staphylococci	108	108	100	107	99.1	3	105	0	-
OXA	Staphylococci	107	107	100	107	100	51	56	0	-
VAN	Enterococci	209	198	94.7	202	96.7	70	139	3	4
VAN	Staphylococci	106	106	100	106	100	0	106	0	0

Predicate Device(s): If the device was cleared using the 510(k) pathway, identify the Predicate Device(s) K/DEN number used to claim substantial equivalence and list them here in a comma separated list exactly as they appear in the text. List the primary predicate first in the list.

K223493

Reference Device(s): Identify the Reference Device(s) K/DEN number and list them here in a comma separated list exactly as they appear in the text.

Not Found

Predetermined Change Control Plan (PCCP) - All Relevant Information for the subject device only (e.g. presence / absence, what scope was granted / cleared under the PCCP, any restrictions, etc).

Not Found

Regulation Number and Section

§ 866.1650 A cellular analysis system for multiplexed antimicrobial susceptibility testing.

(a)
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.(b)
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.

Summary

0

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"

1

(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 (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

2

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

3

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

4

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)

CONTINUE ON A SEPARATE PAGE IF NEEDED.

This section applies only to requirements of the Paperwork Reduction Act of 1995.

DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.

The burden time for this collection of information is estimated to average 79 hours per response. including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to:

Department of Health and Human Services Food and Drug Administration Office of Chief Information Officer Paperwork Reduction Act (PRA) Staff PRAStaff(@fda.hhs.gov

"An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number."

5

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. 617-945-9383

Contact:

Carrene Plummer Tel. 520-405-1462

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
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.

6

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.

7

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

8

. 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.

9

| Device & Predicate
Devices: | K244044
Candidate Device | K223493
Predicate Device |
|-----------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Device Trade Name | PBC Separator with Selux AST
System - GN and GP | PBC Separator with Selux AST
System - GN |
| Device Characteristics | | |
| Indication 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
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. | The PBC Separator with the Selux AST
System is an automated inoculum
preparation system that uses lysis,
centrifugation 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 by
Gram stain. Organism identification is
required for AST result interpretation
and reporting, per the Selux AST
System instructions for use. |
| Source of
Microorganisms | Bacteria from positive blood cultures | Same |
| Device & Predicate
Devices: | K244044
Candidate Device | K223493
Predicate Device |
| Indicated
Antimicrobial/Organism
Combinations | Gram-Negative Organisms:
Amikacin: Acinetobacter baumannii
complex, Escherichia coli,
Klebsiella pneumoniae,
Pseudomonas aeruginosa | Gram-Negative Organisms:
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 | Amoxicillin-Clavulanate: Escherichia
coli, Klebsiella species (including K.
oxytoca, K. pneumoniae), Proteus
mirabilis, Proteus vulgaris |
| | Ampicillin: Escherichia coli,
Proteus mirabilis | Ampicillin: Escherichia coli, Proteus
mirabilis |
| | Ampicillin-Sulbactam:
Acinetobacter baumannii
complex, Citrobacter koseri,
Escherichia coli, Klebsiella
pneumoniae, Proteus mirabilis | Ampicillin-Sulbactam:
Acinetobacter baumannii complex,
Citrobacter koseri, Escherichia
coli, Klebsiella pneumoniae,
Proteus mirabilis |
| | Cefazolin: Escherichia coli,
Klebsiella pneumoniae | 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 | 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: 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 | 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 | Ceftriaxone: Citrobacter freundii
complex, Citrobacter koseri,
Enterobacter cloacae complex,
Escherichia coli, Klebsiella
aerogenes, Klebsiella oxytoca, |
| Device & Predicate
Devices: | K244044
Candidate Device | K223493
Predicate Device |
| | complex, Escherichia coli, | Klebsiella pneumoniae, Proteus |
| | Klebsiella aerogenes, Klebsiella | mirabilis, Serratia marcescens |
| | oxytoca, Klebsiella pneumoniae, | Ciprofloxacin: Citrobacter |
| | Proteus mirabilis, Serratia | freundii complex, Citrobacter |
| | marcescens | koseri, Enterobacter cloacae |
| | Ciprofloxacin: 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, | Ertapenem: Citrobacter freundii |
| | Serratia marcescens, | complex, Citrobacter koseri, |
| | Pseudomonas aeruginosa | Enterobacter cloacae complex, |
| | Ertapenem: Citrobacter freundii | Escherichia coli, Klebsiella |
| | complex, Citrobacter koseri, | aerogenes, Klebsiella oxytoca, |
| | Enterobacter cloacae complex, | Klebsiella pneumoniae, |
| | Escherichia coli, Klebsiella | Morganella morganii, Proteus |
| | aerogenes, Klebsiella oxytoca, | mirabilis, Proteus vulgaris, |
| | Klebsiella pneumoniae, | Serratia marcescens |
| | Morganella morganii, Proteus | Gentamicin: Citrobacter freundii |
| | mirabilis, Proteus vulgaris, | complex, Citrobacter koseri, |
| | Serratia marcescens | Enterobacter cloacae complex, |
| | Gentamicin: Citrobacter freundii | Escherichia coli, Klebsiella aerogenes,
Klebsiella oxytoca, Klebsiella |
| | complex, Citrobacter koseri, | pneumoniae, Morganella morganii, |
| | Enterobacter cloacae complex, | Proteus mirabilis, Proteus vulgaris, |
| | Escherichia coli, Klebsiella | Serratia marcescens, Pseudomonas |
| | aerogenes, Klebsiella oxytoca,
Klebsiella pneumoniae, Morganella | aeruginosa |
| | morganii, Proteus mirabilis, Proteus | Imipenem: Acinetobacter baumannii |
| | vulgaris, Serratia marcescens, | complex, Escherichia coli, Klebsiella |
| | Pseudomonas aeruginosa | pneumoniae |
| | Imipenem: Acinetobacter baumannii | Meropenem: Acinetobacter baumannii |
| | complex, Escherichia coli, Klebsiella | complex, Citrobacter freundii complex, |
| | pneumoniae | Citrobacter koseri, Enterobacter |
| | Meropenem: Acinetobacter | cloacae complex, Escherichia coli, |
| | baumannii complex, Citrobacter | Klebsiella oxytoca, Klebsiella |
| | freundii complex, Citrobacter koseri, | pneumoniae, Morganella morganii, |
| | Enterobacter cloacae complex, | Proteus mirabilis, Proteus vulgaris, |
| | Escherichia coli, Klebsiella oxytoca, | Serratia marcescens, Pseudomonas
aeruginosa |
| | Klebsiella pneumoniae, Morganella | Minocycline: Acinetobacter baumannii |
| | morganii, Proteus mirabilis, Proteus | complex, Escherichia coli, Klebsiella |
| | vulgaris, Serratia marcescens, | pneumoniae |
| | Pseudomonas aeruginosa | Piperacillin-Tazobactam: |
| | Minocycline: Acinetobacter
baumannii complex, Escherichia coli, | Acinetobacter baumannii complex, |
| Device & Predicate
Devices: | K244044
Candidate Device | K223493
Predicate Device |
| | 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

Gram-Positive Organisms:
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 | Citrobacter koseri, Escherichia coli,
Klebsiella pneumoniae, Morganella
morganii, Proteus mirabilis, Proteus
vulgaris, Serratia marcescens,
Pseudomonas aeruginosa
Tobramycin: Escherichia coli,
Klebsiella pneumoniae, Pseudomonas
aeruginosa |
| | Cefoxitin Screen to predict mecA -
mediated oxacillin resistance:
Staphylococcus aureus | |
| Technology | Uses lysis, centrifugation and
sequential optical density
measurements to generate a
McFarland-equivalent suspension. | Same |
| Output/Results Reported | Liquid suspension of bacteria
(McFarland equivalent)
suitable for susceptibility
testing. | Same |
| AST | Selux AST System | Same |

10

11

12

The only difference between the current and predicate device is in the supported antimicrobial agents and organisms in the indications for use. Despite the differences between the PBC Separator with Selux AST System for gram-negative and gram-positive bacteria and the predicate device, the overall risk and safety of system use is not affected.

13

Reproducibility

PBC Separator with Selux AST System intra- and inter-site reproducibility were evaluated by testing a minimum of 5 samples for each of 9 representative antimicrobials at each of three test sites (2 external, 1 internal). Each sample comprised an isolate that was seeded at approximately 10-10.000 CFU into a blood culture bottle with approximately 10 mL of fresh human blood from a healthy donor and then loaded into an FDA-cleared continuous monitoring blood culture system (BD BACTEC or bioMerieux BacT/ALERT VIRTUO) until positive growth was detected. The positive blood culture bottle was then removed and processed using the PBC Separator with Selux AST System. Each sample was tested in triplicate using three different inoculums prepared by the PBC Separator on each of three days it was tested at each site. There is thus a minimum of 3 × 3 = 9 results per sample and 9 × 5 = 45 results per antimicrobial at a single site. The acceptance criteria were defined as ≥95% best-case reproducibility and a ≥89% worst-case reproducibility for inter- and intra-site reproducibility.

The intra-site reproducibility is given in the table below. In each case, the best-and worst-case intra-site reproducibility was ≥ 97%. The results of cefoxitin screen (FOX SCN) tests are either positive or negative.

Intra-Site Reproducibility
Antimicrobial	N	Best-Case	Worst Case
Ampicillin	45	100%	100%
Ceftaroline	45	100%	100%
Daptomycin	90	100%	100%
Linezolid	90	98.9%	98.9%
Oxacillin	45	100%	97.8%
Vancomycin	81	100%	100%

For inter-site reproducibility, there are a minimum of 3 × 3 × 3 = 27 results per sample and 27 × 5 = 135 results per antimicrobial. The inter-site reproducibility is given in the table below. In each case, the best-case inter-site reproducibility was ≥ 95%, and worst-case inter-site reproducibility was > 94%. The results of cefoxitin screen (FOX SCN) tests are either positive or negative. To assess the reproducibility of FOX SCN, test results were calculated as reproducible if they exactly matched the modal result of the isolate. Worst-case reproducibility is not applicable and was not calculated. The results of cefoxitin screen are 134/135 (99.3%) and 45/45 (100%) for inter-site and intra-site reproducibility, respectively.

Inter-Site Reproducibility
Antimicrobial	N	Best-Case	Worst Case
Ampicillin	135	100%	100%
Ceftaroline	135	100%	100%
Daptomycin	270	100%	100%
Linezolid	270	99.6%	99.6%
Oxacillin	135	95.6%	94.8%
Vancomycin	243	100%	100%

14

Other Analytical Studies:

Post-Positivity Sample Stability Study

The amount of time between the registration of positive growth for a sample and the initiation of processing with the PBC Separator was evaluated. Selux AST System MIC results from samples run with the PBC Separator 16 and 18 hours after registering positive growth in a continuous monitoring blood culture system were compared with t = 0 hr control MIC results from samples processed on the PBC Separator immediately after registering positive growth. At least three replicates of one species from each indicated antimicrobial/organism reporting group were tested per drug per timepoint. The total EA for all results at the 16-hour timepoints compared with the 0-hour timepoint was 100.0% (30/30 results in EA). As noted in the Limitations section, positive blood bottles should be processed promptly after ringing positive on a continuous blood culture monitoring system. In the case of unavoidable delays or if the need for sample re-testing arises, bottles must be processed within 16 hours post ring.

Blood Culture Bottle Compatibility Study

Eleven types of blood culture bottles listed below were evaluated with the PBC Separator with Selux AST System.

Bottle Type	Blood Culture System Compatibility
BACTEC Plus Aerobic	BD BACTEC
BACTEC Plus Anaerobic	BD BACTEC
BACTEC Standard Aerobic	BD BACTEC
BACTEC Standard Anaerobic	BD BACTEC
BACTEC Lytic Anaerobic	BD BACTEC
BACTEC Peds Plus	BD BACTEC
BacT/ALERT FA Plus	BacT/ALERT VIRTUO
BacT/ALERT FN Plus	BacT/ALERT VIRTUO
BacT/ALERT SA	BacT/ALERT VIRTUO
BacT/ALERT SN	BacT/ALERT VIRTUO
BacT/ALERT PF Plus	BacT/ALERT VIRTUO

Eleven types of blood culture bottles incubated in BD BACTEC and bioMérieux BacT/ALERT VIRTUO continuous monitoring blood culture systems were evaluated with the PBC Separator with Selux AST System. Bacterial samples were seeded at clinically relevant concentrations into the blood culture bottles with the manufacturer recommended volume of human blood. Seeded bottles were loaded into a continuous monitoring blood culture system and incubated until positivity. Positive blood culture samples were then processed with the PBC Separator with Selux AST System. One isolate from each reporting group was tested with three replicates per bottle type and evaluated with all claimed antimicrobials. Aerobic bottles were seeded with E. faecalis and S. aureus.

15

Selux AST System MIC results from tested bottle types showed >89.9% essential agreement to the reference method. Across all aerobic bottle types there was 99.4% EA (179/180 results in EA) and each aerobic bottle type had EA of ≥96.7%. Across all anaerobic bottle types there was 99.3% EA (149/150 results in EA) and each anaerobic bottle type had EA of ≥96.7%. Cefoxitin Screen was considered separately since results are either positive and showed 100% agreement with expected results except for Cefoxitin-Staphylococci, which demonstrated 66.7% (2/3) out-ofagreement results in BD BACTEC Aerobic Plus bottles.

PBC Separator with Selux AST System performance with Aerobic BD BACTEC bottles is provided below. All Selux System MIC results are compared to the reference method.

| Antimicrobial
Agent | Organism
Group | Standard Aerobic | | | Aerobic Plus | | | Peds Plus | | |
|------------------------|-------------------|------------------|-----|-------|--------------|-----|-------|--------------|-----|-------|
| | | #
Results | #EA | %EA | #
Results | #EA | %EA | #
Results | #EA | %EA |
| Ampicillin | Enterococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| Ceftaroline | Staphylococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| Daptomycin | Enterococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| | Staphylococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| | Total | 6 | 6 | 100.0 | 6 | 6 | 100.0 | 6 | 6 | 100.0 |
| Linezolid | Enterococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| | Staphylococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| | Total | 6 | 6 | 100.0 | 6 | 6 | 100.0 | 6 | 6 | 100.0 |
| Oxacillin | Staphylococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| Vancomycin | Enterococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| | Staphylococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| | Total | 6 | 6 | 100.0 | 6 | 6 | 100.0 | 6 | 6 | 100.0 |
| All
Antimicrobials | Enterococci | 12 | 12 | 100.0 | 12 | 12 | 100.0 | 12 | 12 | 100.0 |
| | Staphylococci | 18 | 18 | 100.0 | 18 | 17 | 94.4 | 18 | 18 | 100.0 |
| | Total | 30 | 30 | 100.0 | 30 | 29 | 96.7 | 30 | 30 | 100.0 |

PBC Separator with Selux AST System performance with Aerobic bioMérieux bottles is provided below. All Selux System MIC results are compared to the reference method.

| Antimicrobial
Agent | Organism
Group | SA(Standard Aerobic)

Results | SA(Standard Aerobic)
#EA | SA(Standard Aerobic)
%EA | FAPlus (Resin Aerobic)

Results | FAPlus (Resin Aerobic)
#EA | FAPlus (Resin Aerobic)
%EA | PF Plus (Pediatric)

Results | PF Plus (Pediatric)
#EA | PF Plus (Pediatric)
%EA |
|------------------------|-------------------|--------------------------------------|-----------------------------|-----------------------------|----------------------------------------|-------------------------------|-------------------------------|-------------------------------------|----------------------------|----------------------------|
| Ampicillin | Enterococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| Ceftaroline | Staphylococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| Daptomycin | Enterococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| Daptomycin | Staphylococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| | Total | 6 | 6 | 100.0 | 6 | 6 | 100.0 | 6 | 6 | 100.0 |
| Linezolid | Enterococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| Linezolid | Staphylococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| | Total | 6 | 6 | 100.0 | 6 | 6 | 100.0 | 6 | 6 | 100.0 |
| Oxacillin | Staphylococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| Vancomycin | Enterococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| Vancomycin | Staphylococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| | Total | 6 | 6 | 100.0 | 6 | 6 | 100.0 | 6 | 6 | 100.0 |
| All
Antimicrobials | Enterococci | 12 | 12 | 100.0 | 12 | 12 | 100.0 | 12 | 12 | 100.0 |
| | Staphylococci | 18 | 18 | 100.0 | 18 | 18 | 100.0 | 18 | 18 | 100.0 |
| | Total | 30 | 30 | 100.0 | 30 | 30 | 100.0 | 30 | 30 | 100.0 |

16

| Antimicrobial
Agent | Organism
Group | #
Results | #EA | %EA | Standard Anaerobic | | | Anaerobic Plus | | | Lytic Anaerobic | | |
|------------------------|-------------------|--------------|-----|-------|--------------------|-----|-------|----------------|-----|-------|-----------------|-----|-------|
| | | | | | #
Results | #EA | %EA | #
Results | #EA | %EA | #
Results | #EA | %EA |
| Ampicillin | Enterococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| Ceftaroline | Staphylococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| Daptomycin | Enterococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| | Staphylococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| | Total | 6 | 6 | 100.0 | 6 | 6 | 100.0 | 6 | 6 | 100.0 | 6 | 6 | 100.0 |
| Linezolid | Enterococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| | Staphylococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| | Total | 6 | 6 | 100.0 | 6 | 6 | 100.0 | 6 | 6 | 100.0 | 6 | 6 | 100.0 |
| Oxacillin | Staphylococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| Vancomycin | Enterococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 2 | 66.7 | 3 | 3 | 100.0 |
| | Staphylococci | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| | Total | 6 | 6 | 100.0 | 6 | 6 | 100.0 | 6 | 5 | 83.3 | 6 | 6 | 100.0 |
| All
Antimicrobials | Enterococci | 12 | 12 | 100.0 | 12 | 12 | 100.0 | 12 | 11 | 91.7 | 12 | 12 | 100.0 |
| | Staphylococci | 18 | 18 | 100.0 | 18 | 18 | 100.0 | 18 | 18 | 100.0 | 18 | 18 | 100.0 |
| | Total | 30 | 30 | 100.0 | 30 | 30 | 100.0 | 30 | 29 | 96.7 | 30 | 30 | 100.0 |

PBC Separator with Selux AST System performance with Anaerobic BD BACTEC bottles is provide below. All Selux System MIC results are compared to the reference method.

PBC Separator with Selux AST System performance with Anaerobic bioMérieux bottles is provided below. All Selux System MIC results are compared to the reference method.

| Antimicrobial
Agent | Organism
Group | FN Plus
(Resin Anaerobic) | | (Standard Anaerobic) | | |------------------------|------------ | | Results | #EA | %EA Results | #EA | %EA | Ampicillin | Enterococci | Ceftaroline | Staphylococci | Daptomycin | Enterococci | | Staphylococci | | Total | Linezolid | Enterococci | | Staphylococci | | Total | Oxacillin | Staphylococci | Vancomycin | Enterococci | | Staphylococci | | Total | All
Antimicrobials | Enterococci | 12 | | Staphylococci | | Total | SN
|
-------|------------------------------|-----|-------|----------------------------|-----|-------|
| #
| #
|
| 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| 6 | 6 | 100.0 | 6 | 6 | 100.0 |
| 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| 6 | 6 | 100.0 | 6 | 6 | 100.0 |
| 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| 3 | 3 | 100.0 | 3 | 3 | 100.0 |
| 6 | 6 | 100.0 | 6 | 6 | 100.0 |
| 12 | 100.0 | 12 | 12 | 100.0 |
| 18 | 18 | 100.0 | 18 | 18 | 100.0 |
| 30 | 30 | 100.0 | 30 | 30 | 100.0 |

17

Interfering Substances Testing

The effect of the presence of endogenous and exogenous interferents that may be present in a blood culture was evaluated on the PBC Separator with Selux AST System for gram-positive organisms. Studies were performed by seeding the two most common gram-positive species isolated from blood cultures, E. faecalis and S. aureus, at clinically relevant concentrations into non-resin blood culture bottles with the manufacturer recommended volume of human blood. Potential interferents were seeded into the blood culture bottles at the time of bacterial seeding and prior to incubation in the blood culture system. Control samples to which no interferents were added were processed in parallel. Seeded bottles were loaded into a continuous monitoring blood culture system and incubated until positivity. Positive blood culture samples were then processed with the PBC Separator with Selux AST System.

Endogenous interferents evaluated on the system included red blood cells (RBCs), white blood cells (WBCs), platelets, triglycerides, gamma globulin, and conjugated and unconjugated bilirubin. Exogenous interferents included available oral antibiotics, including cefpodoxime, ciprofloxacin, penicillin, and gentamicin were evaluated. Each was spiked into a non-resin blood culture bottle with healthy donor blood at the peak serum level for oral administration of each agent.

The PBC Separator with Selux AST System MIC results showed >89.9% EA for every interferent tested when compared with PBC Separator with Selux AST System results for the same organism run in a control condition (no interferent). Cefoxitin Screen was considered separately since results are either positive or negative. No interference was observed, i.e., results exactly matched the control result for all endogenous and exogenous interferents.

PBC Separator with Selux AST System performance is provided below for the following endogenous interferents: Red Blood Cells, White Blood Cells, and Platelets.

| Antimicrobial | Indicated
Organism(s) | #EA/
Total | %EA | #EA/
Total | %EA | #EA/
Total | %EA |
|---------------|--------------------------|------------------------------|--------|----------------------------------------|--------|---------------------------|--------|
| | | Red Blood Cells
(20 g/dL) | | White Blood Cells
(12,000 cells/µL) | | Platelets
(450,000/µL) | |
| Ampicillin | Enterococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| Ceftaroline | Staphylococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| Daptomycin | Enterococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Staphylococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Combined | 6/6 | 100.0% | 6/6 | 100.0% | 6/6 | 100.0% |
| Linezolid | Enterococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Staphylococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Combined | 6/6 | 100.0% | 6/6 | 100.0% | 6/6 | 100.0% |
| Oxacillin | Staphylococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| Vancomycin | Enterococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Staphylococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Combined | 6/6 | 100.0% | 6/6 | 100.0% | 6/6 | 100.0% |

18

PBC Separator with Selux AST System performance is provided below for the following endogenous interferents: Conjugated Bilirubin, Unconjugated Bilirubin, Triglycerides, and Gamma Globulins.

| Antimicrobial | Indicated
Organism(s) | Conjugated
Bilirubin
(475 µmol/L) | | Unconjugated
Bilirubin
(684 µmol/L) | | Triglycerides
(16.94 mmol/L) | | Gamma Globulins
(16.94 mmol/L) | |
|---------------|--------------------------|-----------------------------------------|--------|-------------------------------------------|--------|---------------------------------|--------|-----------------------------------|--------|
| | | #EA /
Total | %EA | #EA /
Total | %EA | #EA /
Total | %EA | #EA /
Total | %EA |
| Ampicillin | Enterococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| Ceftaroline | Staphylococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| Daptomycin | Enterococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Staphylococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Combined | 8/8 | 100.0% | 8/8 | 100.0% | 8/8 | 100.0% | 8/8 | 100.0% |
| Linezolid | Enterococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Staphylococci | 2/3 | 66.7% | 3/3 | 100.0% | 3/3 | 100.0% | 2/3 | 66.7% |
| | Combined | 5/6 | 83.3% | 6/6 | 100.0% | 6/6 | 100.0% | 5/6 | 83.3% |
| Oxacilin | Staphylococci | 3/3 | 100.0% | 3/3 | 100.0% | 2/3 | 66.7% | 3/3 | 100.0% |
| | Enterococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| Vancomycin | Staphylococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Enterococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Combined | 6/6 | 100.0% | 6/6 | 100.0% | 6/6 | 100.0% | 6/6 | 100.0% |

PBC Separator with Selux AST System performance is provided below with the following exogenous interferents: Ciprofloxacin, Cefpodoxime, Gentamicin, and Penicillin.

| Antimicrobial | Indicated
Organism(s) | Ciprofloxacin
(3.6 µg/mL) | | Cefpodoxime
(2.3 µg/mL) | | Gentamicin
(6 µg/mL) | | Penicillin
(6 µg/mL) | |
|---------------|--------------------------|------------------------------|--------|----------------------------|--------|-------------------------|--------|-------------------------|--------|
| | | #EA/Total | %EA | #EA/Total | %EA | #EA/Total | %EA | #EA/Total | %EA |
| Ampicillin | Enterococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| Ceftaroline | Staphylococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| Daptomycin | Enterococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Staphylococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Combined | 6/6 | 100.0% | 6/6 | 100.0% | 6/6 | 100.0% | 6/6 | 100.0% |
| Linezolid | Enterococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Staphylococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Combined | 6/6 | 100.0% | 6/6 | 100.0% | 6/6 | 100.0% | 6/6 | 100.0% |
| Oxacillin | Staphylococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| Vancomycin | Enterococci | 3/3 | 100.0% | 1/3 | 33.3% | 3/3 | 100.0% | 1/3 | 33.3% |
| | Staphylococci | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% |
| | Combined | 6/6 | 100.0% | 4/6 | 66.7% | 6/6 | 100.0% | 4/6 | 66.7% |

19

Clinical Studies

| Antimicrobial | Reporting
Group | Reportable Range
in Test Device | FDA Breakpoints | | | |
|---------------|--------------------|------------------------------------|-----------------|-----|------|-----|
| | | | S | SDD | I | R |
| Ampicillin | Enterococci | ≤2 to ≥64 | ≤8 | | | ≥16 |
| Ceftaroline | S. aureus | ≤0.25 to ≥16 | ≤1 | 2-4 | | ≥8 |
| | E. faecium | 1 to ≥32 | | ≤4 | | ≥8 |
| Daptomycin | E. faecalis | ≤1 to ≥32 | ≤2 | | 4 | ≥8 |
| | S. aureus | ≤0.25 to ≥8 | ≤1 | | | |
| Linezolid | Enterococci | ≤0.5 to ≥16 | ≤2 | | 4 | ≥8 |
| | S. aureus | ≤1 to ≥32 | ≤4 | | | ≥8 |
| Oxacillin | S. aureus | ≤0.5 to ≥16 | ≤2 | | | ≥4 |
| | Enterococci | ≤1to ≥64 | ≤4 | | 8-16 | ≥32 |
| Vancomycin | S. aureus | ≤0.5 to ≥32 | ≤2 | | 4-8 | ≥16 |

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

Clinical performance testing with the PBC Separator with Selux AST System for gram-positive organisms was performed at three test sites using fresh positive blood culture samples left over from routine clinical care and seeded samples. Seeded samples were prepared using banked frozen isolates seeded at 10-10,000 CFU into blood culture bottles together with approximately 10 mL of fresh human blood from a healthy donor and then loaded into an FDA-cleared continuous monitoring blood culture system until positive growth was detected. Positive blood bottles were tested with the PBC Separator and Selux AST System. Fresh positive blood culture and seeded samples were collected from clinical sites to represent geographic diversity across the continental U.S. A total of 247 clinical (64 fresh and 183 seeded) and 75 challenge isolates from 2 Enterococci species and Staphylococcus aureus were tested to evaluate the PBC Separator performance for 7 antimicrobials with the Selux AST System. Depending on the spectrum of activity, breakpoints, and the claimed organisms (species/group) for each antimicrobial on the panel, the number of datapoints for the various antimicrobial-organisms tested varied and ranged from 100 (e.g., E. faecium/Daptomycin) to 211 (e.g., Enterococci/Linezolid).

PBC Separator with Selux AST System performance for gram-positive organisms was determined by comparing Selux AST System results from PBC Separator-prepared inoculums to triplicate broth microdilution results performed at an independent reference laboratory. The PBC Separator with the Selux AST System meets performance criteria for each indication and is given in the table below, where performance is summarized by drug and reporting group. Additionally, QC testing was performed every day testing was performed at each site and met the 95% performance criteria for all antimicrobials.

20

| Antimicrobial | Organism Group | Total
Tested | # in EA | % EA | Total
Eval | # Eval in
EA | % EA of
Eval | # in
CA | % CA | # R | # S | # VMJ | # MAJ | # MIN |
|---------------|-----------------------|-----------------|---------|------|---------------|-----------------|-----------------|------------|------|-----|-----|-------|-------|-------|
| AMP | Enterococci | 210 | 209 | 99.5 | 4 | 3 | 75 | 210 | 100 | 92 | 118 | 0 | 0 | - |
| CPT | Staphylococci | 111 | 110 | 99.1 | 55 | 54 | 98.2 | 105 | 94.6 | 0 | 109 | 0 | 0 | 6 |
| | Enterococcus faecalis | 103 | 100 | 97.1 | 3 | 0 | 0 | 100 | 97.1 | 0 | 103 | 0 | 2 | 1 |
| DAP | Enterococcus faecium | 100 | 94 | 94 | 12 | 6 | 50 | 98 | 98 | 0 | 100 | 0 | 2 | - |
| | Staphylococci | 108 | 108 | 100 | 0 | 0 | - | 108 | 100 | 0 | 108 | 0 | 0 | - |
| FOX SCN | Staphylococci | 109 | - | - | - | - | - | 109 | 100 | 54 | 55 | 0 | 0 | - |
| | Enterococci | 211 | 210 | 99.5 | 193 | 192 | 99.5 | 210 | 99.5 | 0 | 211 | 0 | 1 | 0 |
| LNZ | Staphylococci | 108 | 108 | 100 | 4 | 4 | 100 | 107 | 99.1 | 3 | 105 | 0 | 0 | - |
| OXA | Staphylococci | 107 | 107 | 100 | 4 | 4 | 100 | 107 | 100 | 51 | 56 | 0 | 0 | - |
| | Enterococci | 209 | 198 | 94.7 | 21 | 10 | 47.6 | 202 | 96.7 | 70 | 139 | 0 | 3 | 4 |
| VAN | Staphylococci | 106 | 106 | 100 | 18 | 18 | 100 | 106 | 100 | 0 | 106 | 0 | 0 | 0 |

PBC Separator with Selux AST System MIC values for the following antimicrobial/organism combinations tended to be at least one doubling dilution lower than the reference MIC value:

Daptomycin: E. faecium, S. aureus
. Linezolid: E. faecalis, S. aureus

PBC Separator with Selux AST System MIC values for the following antimicrobial/organism combinations tended to be at least one doubling dilution higher than the reference MIC value:

Ceftaroline: S. aureus ●
Vancomycin: E. faecalis .

Conclusion

Based on the studies and testing conducted to demonstrate safety and effectiveness and the similarities between the current and predicate devices, the PBC Separator with Selux AST System for gram-negative and gram-positive bacteria was determined to be substantially equivalent to the predicate device (K223493).