PBC Separator with Selux AST System

K223493 · Selux Diagnostics, Inc. · QZX · Feb 15, 2024 · Microbiology

Device Facts

Record IDK223493
Device NamePBC Separator with Selux AST System
ApplicantSelux Diagnostics, Inc.
Product CodeQZX · Microbiology
Decision DateFeb 15, 2024
DecisionSESE
Submission TypeTraditional
Regulation21 CFR 866.1650
Device ClassClass 2
AttributesReal-World Evidence

Real-World Evidence

SubmissionDeviceSponsorRWD SourcesRWE Use SummaryKey Tags
K223493 · Feb 15, 2024PBC Separator with Selux AST SystemSelux Diagnostics, Inc.Residual positive blood culture samples from routine clinical careClinical performance evaluation of the PBC Separator with Selux AST System by comparing results from routine clinical residual samples and seeded samples against a reference broth microdilution method.Residual clinical samples; Clinical performance study; Antimicrobial susceptibility testing

Clinical Evidence

Study DesignPopulationComparatorKey Endpoints
Retrospective evaluation of residual clinical samples and prospective evaluation of seeded samplesPositive blood culture samples (Enterobacterales, Acinetobacter baumannii complex, and Pseudomonas aeruginosa); Sample Size: 469 total (162 fresh clinical, 307 seeded); Number of Sites: 4Triplicate broth microdilution reference methodEssential Agreement (EA) and Category Agreement (CA) for antimicrobial susceptibility testing

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 by Gram stain. Organism identification is required for AST result interpretation and reporting, per the Selux AST System instructions for use.

Device Story

The PBC Separator is an automated sample preparation instrument used with the Selux AST System. It accepts 9 mL of monomicrobial, Gram-negative positive blood culture samples. The device uses lysis, centrifugation, and sequential optical density measurements to remove blood components and tune the bacterial suspension to a 0.65-0.8 McFarland equivalent. The resulting 1 mL inoculum is manually transferred to the Selux AST System for quantitative MIC determination. The system is used in clinical laboratories by technicians. It provides MIC values for specific antimicrobial-organism combinations, aiding clinicians in selecting appropriate antibiotic therapy. The device benefits patients by providing faster AST results (under 7 hours on average) compared to traditional methods, facilitating timely targeted treatment.

Clinical Evidence

Performance was evaluated using 469 clinical (162 fresh, 307 stock) and 87 challenge isolates. Testing compared Selux AST System MIC results from PBC Separator-prepared inocula against modal broth microdilution reference results. Primary endpoints included Essential Agreement (EA) and Categorical Agreement (CA). Overall, EA and CA were ≥90%. Reproducibility studies showed ≥95% inter-site and intra-site performance. Interference studies evaluated endogenous/exogenous substances; specific limitations were noted for Piperacillin-Tazobactam and Tobramycin. Trending analysis identified specific antimicrobial/organism combinations with systematic MIC shifts.

Technological Characteristics

The PBC Separator uses lysis, centrifugation, and an onboard spectrophotometer for optical density measurements to tune inoculum density. It is a benchtop instrument with associated consumables (Sample Tube, Inoculum Tube, Reagent Kit). It operates via automated liquid handling and centrifugation. Connectivity includes barcode association with the Selux Site Services central workstation. Software version 61.6 (firmware).

Indications for Use

Indicated for automated inoculum preparation from positive blood culture samples (monomicrobial, gram-negative rods) for quantitative antimicrobial susceptibility testing (AST) using the Selux AST System. Requires prior organism identification for result interpretation. Performance demonstrated for specific antimicrobial agents and organisms including Acinetobacter baumannii complex, Citrobacter species, Enterobacter cloacae complex, Escherichia coli, Klebsiella species, Morganella morganii, Proteus species, Pseudomonas aeruginosa, and Serratia marcescens.

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

Submission Summary (Full Text)

{0} **FDA** U.S. FOOD & DRUG ADMINISTRATION # **510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY ASSAY AND INSTRUMENT** # **I Background Information:** # **A 510(k) Number** K223493 # **B Applicant** Selux Diagnostics, Inc # **C Proprietary and Established Names** PBC Separator with Selux AST System # **D Regulatory Information** | Product Code(s) | Classification | Regulation Section | Panel | | --- | --- | --- | --- | | QZX | Class II | 21 CFR 866.1650 - A Cellular Analysis System For Multiplexed Antimicrobial Susceptibility | MI - Microbiology | | LON | Class II | 21 CFR 866.1645 - Fully automated short-term incubation cycle antimicrobial susceptibility system | MI - Microbiology | | LTT | Class II | 21 CFR 866.1640 - Antimicrobial susceptibility test powder | MI - Microbiology | | LTW | Class II | 21 CFR 866.1640 - Antimicrobial susceptibility test powder | MI - Microbiology | # **II Submission/Device Overview:** # **A Purpose for Submission:** To obtain a substantial equivalence determination for the preparation of a McFarland Standard equivalent from positive blood culture samples using the PBC Separator to determine the Food and Drug Administration 10903 New Hampshire Avenue Silver Spring, MD 20993-0002 www.fda.gov {1} minimum inhibitory concentration of specific antimicrobial agents with specific Gram-negative organisms with the Selux AST System. ## **B Measurand:** Standardized suspension of gram-negative bacteria prepared from positive blood culture samples used in conjunction with the Selux AST System with the following antimicrobial agents: | Antimicrobial | Reportable Range | | --- | --- | | Amikacin | ≤0.12 to ≥256 µg/mL | | Amoxicillin-Clavulanate | ≤2 to ≥128 µg/mL | | Ampicillin | ≤2 to ≥128 µg/mL | | Ampicillin-Sulbactam | ≤0.5 to ≥128 µg/mL | | Cefazolin | ≤0.12 to ≥128 µg/mL | | Cefepime | ≤0.5 to ≥128 µg/mL | | Ceftazidime | ≤0.25 to ≥256 µg/mL | | Ceftazidime-Avibactam | ≤0.12 to ≥64 µg/mL | | Ceftriaxone | ≤0.25 to ≥32 µg/mL | | Ciprofloxacin | ≤0.03 to ≥16 µg/mL | | Ertapenem | ≤0.03 to ≥16 µg/mL | | Gentamicin | ≤0.5 to ≥64 µg/mL | | Imipenem | ≤0.25 to ≥64 µg/mL | | Meropenem | ≤0.12 to ≥64 µg/mL | | Piperacillin-Tazobactam | ≤0.25 to ≥512 µg/mL | | Tobramycin | ≤0.12 to ≥128 µg/mL | ## **C Type of Test:** Positive blood culture processor that prepares a tuned inoculum for use with the Selux AST System, a quantitative antimicrobial susceptibility test system that utilizes colorimetric, oxidation-reduction and growth-based strategies to determine the minimum inhibitory concentration (MIC) of specific antimicrobial agents for specific organisms. ## **III Intended Use/Indications for Use:** ### **A Intended Use(s):** 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. ### **B Indication(s) 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 by Gram stain. Organism identification is required for AST result interpretation and reporting, per the Selux AST System instructions for use. K223493 - Page 2 of 42 {2} Inoculum preparation by the PBC Separator was evaluated for use with the Selux AST System.. 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*, *K. 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 oxytoca*, *Klebsiella pneumoniae*, *Morganella morganii*, *Proteus mirabilis*, *Proteus vulgaris*, *Serratia marcescens* Gentamicin: *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* 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* K223493 - Page 3 of 42 {3} 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* 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 species not indicated for testing with the device, for epidemiologic testing, and for recovery of organisms present in microbial samples. ### C Special Conditions for Use Statement(s): Rx - For Prescription Use Only - • The PBC Separator with Selux AST System cannot be used for any clinical specimens other than monomicrobial positive blood cultures. - • Performance of PBC Separator-prepared inoculum for use with the Selux AST System has only been established using the antimicrobials listed in the Indications for Use. - • Results from the Selux AST System obtained using inocula prepared by the PBC Separator should only be reported for antimicrobials and species indicated in the PBC Separator Indications for Use. - • The use of the PBC Separator with Selux AST System does not eliminate the need for subculture of the positive blood culture. - • If the subculture (purity) plate indicates the sample is polymicrobial, the AST results should be voided, and susceptibility testing on each isolate using a standard inoculum preparation should be performed. - • The performance of the PBC Separator has only been evaluated with the following blood culture bottles: - • BD BACTEC Plus Aerobic - • BD BACTEC Plus Anaerobic - • BD BACTEC Standard Aerobic - • BD BACTEC Standard Anaerobic - • BD BACTEC Lytic Anaerobic - • BD BACTEC Peds Plus - • bioMérieux BacT/ALERT FA Plus Aerobic - • bioMérieux BacT/ALERT FN Plus Anaerobic - • bioMérieux BacT/ALERT SA Standard Aerobic - • bioMérieux BacT/ALERT SN Standard Anaerobic - • bioMérieux BacT/ALERT PF Plus Pediatric Aerobic - • PBC samples should be promptly prepared and loaded into the PBC Separator following bottle ring from a continuous monitoring blood culture system, where possible. In the case of instrument errors or if re-testing is needed, PBC samples must be processed within 16 hours post bottle ring. - • The tuned inoculum must be used within 45 minutes to maintain the appropriate organism concentration. K223493 - Page 4 of 42 {4} The following limitations were added to the device labeling based on performance demonstrated in the current submission: - Perform an alternative method of testing prior to reporting of results for the following antibiotic/organism combination: Cefazolin-E. coli when the Selux AST System MIC from a PBC Separator inoculum is 4 μg/mL due to the occurrence of minor errors resulting in a category agreement below 90%. - An essential agreement <90% and very major errors were observed when testing Piperacillin-Tazobactam with K. pneumoniae with all evaluated potential interferents. - An essential agreement <90% and minor errors were observed when testing Tobramycin with E. coli and K. pneumoniae with the potential interferent cefpodoxime. - The ability of the PBC Separator and Selux AST system to detect resistance in the following antimicrobial/organism combinations is unknown because an insufficient number of resistant isolates were available at the time of comparative testing. ○ Amoxicillin-Clavulanate: P. mirabilis, P. vulgaris ○ Cefepime: C. freundii complex, C. koseri, K. aerogenes, P. mirabilis, P. vulgaris, S. marcescens ○ Ceftazidime-Avibactam: C. freundii complex, C. koseri, E. cloacae complex, E. coli, K. aerogenes, K. oxytoca, M. morganii, P. mirabilis, P. vulgaris, S. marcescens ○ Ceftriaxone: C. koseri, P. mirabilis ○ Ciprofloxacin: C. koseri, K. aerogenes, P. vulgaris ○ Ertapenem: C. freundii complex, K. aerogenes, K. oxytoca, M. morganii, P. mirabilis, P. vulgaris ○ Gentamicin: C. freundii complex, C. koseri, K. aerogenes, P. vulgaris, S. marcescens ○ Meropenem: C. freundii complex, C. koseri, E. cloacae complex, E. coli, K. oxytoca, M. morganii, P. mirabilis, P. vulgaris, S. marcescens ### D Special Instrument Requirements: PBC Separator, software version 61.6 (instrument firmware) Selux AST System, software version 1.7.110 ### IV Device/System Characteristics: ### A 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 tuned McFarland-equivalent suspensions from positive blood culture bottles that have rang positive on a continuous monitoring blood culture system. Inoculums containing monomicrobial, gram negative bacteria are used with the Selux AST System for quantitative minimum inhibitory concentration (MIC) determination of specific antimicrobial-organism combinations. The PBC Separator is comprised of the instrument, software, and associated consumables. The PBC Separator can process up to two positive blood culture samples at once. Within a biosafety cabinet, 9 mL of blood from a positive blood culture bottle that has been confirmed as monomicrobial is transferred to the Selux Sample Tube. The Sample Tube is loaded into the K223493 - Page 5 of 42 {5} PBC Separator along with an empty final Inoculum tube and the PBC Separator Reagent Kit. The software also prompts the user to load racks of pipette tips as needed. The PBC Separator Reagent Kit serves as the waste receptable into which all biohazardous waste is deposited during the separation process and can be disposed of appropriately after processing. After the samples are loaded, the user follows the prompts on the user interface to start processing, which requires 45-55 minutes based on if one or two samples are being processed. The PBC Separator software associates the barcode identifier on the Inoculum Tube with the barcode identifier on the Sample Tube and transmits this information to the Selux Site Services central workstation to ensure sample traceability. Within the instrument, the PBC Separator uses a series of centrifugation and lysis steps to remove blood components and most soluble components. Saline is added and optical density is determined to achieve a density suitable for AST (defined as 0.65-0.8 McFarland equivalent, when used with the Selux AST System). The user is notified when the sample processing is completed and is prompted to retrieve the sample components within 45 minutes. The user then manually transfers the tuned inoculum in the Selux Inoculum Tube (a volume of 1 mL) to the Selux AST System Sample Prep station for AST processing. Within the Selux AST System, the appropriate panel will be inoculated, the panel will be processed, and AST results will be generated. A complete description of the Selux AST System can be found in the K211759 and K211748 decision summaries. The Selux AST System is designed so that only Gram stain information is required to select the proper antimicrobial panel and initiate testing. Gram stain information is not needed to start sample processing with the PBC Separator but is required prior to AST so the appropriate panel can be selected. The PBC Separator with Selux AST System does not provide organism identification (ID). Although the PBC Separator sample processing and Selux AST System testing can be performed without species-level ID, an organism ID is needed for the Selux AST System to report AST results. Species ID can be performed by an appropriate FDA-cleared method and either entered manually into the Selux System or automatically downloaded from the applicable laboratory information system (LIS). The PBC Separator and Selux AST System can provide results from positive blood culture in under 7 hours on average. Within the results interface, AST results will include the MIC values for each indicated antimicrobial. Antimicrobials that are indicated for use with the Selux AST System when testing from isolated colonies but not from inocula prepared with the PBC Separator will be noted as “NC” (not claimed) and MIC values will not be reported. The same is true for antimicrobials and/or organisms that are indicated for use with the Selux AST System when tested from positive blood culture inocula prepared by the PBC Separator. As shown in **Figure 1** below, the PBC Separator is integrated into the Selux AST System for preparing bacterial inocula from positive blood culture for use with the system, which includes the Inoculator and Analyzer instruments. K223493 - Page 6 of 42 {6} Selux AST System ![img-0.jpeg](img-0.jpeg) Figure 1. The PBC Separator as a component of the Selux AST System, which includes the Inoculator and Analyzer instruments. The reportable MIC ranges are shown in Table 1 below. Table 1. Reportable MIC Ranges and Organism-Specific Breakpoints for Antimicrobials Tested with the PBC Separator with Selux AST System. | Antimicrobial | Indicated Organism Group | Selux AST System Reportable Range (μg/mL) | FDA-Recognized/Approved Breakpoints * (μg/mL) | | | | --- | --- | --- | --- | --- | --- | | | | | S | I | R | | Amikacin | Acinetobacter baumannii complex | ≤0.12 to ≥256 | ≤16 | 32 | ≥64 | | | Enterobacterales | ≤2 to ≥256 | ≤16 | 32 | ≥64 | | | Pseudomonas aeruginosa | ≤0.12 to ≥256 | ≤16 | 32 | ≥64 | | Amoxicillin-Clavulanate | Enterobacterales | ≤2 to ≥128 | ≤8 | 16 | ≥32 | | Ampicillin | Enterobacterales | ≤2 to ≥128 | ≤8 | 16 | ≥32 | | Ampicillin-Sulbactam | Acinetobacter baumannii complex | ≤2 to ≥128 | ≤8 | 16 | ≥32 | | | Enterobacterales | ≤0.5 to ≥128 | ≤8 | 16 | ≥32 | | Cefazolin | Enterobacterales | ≤0.12 to ≥128 | ≤2 | 4 | ≥8 | | Cefepime | Enterobacterales | ≤0.5 to ≥32 | ≤2 | 4-8 | ≥16 | | | Pseudomonas aeruginosa | ≤0.25 to ≥128 | ≤8 | - | ≥16 | | Ceftazidime | Enterobacterales | ≤0.25 to ≥64 | ≤4 | 8 | ≥16 | | | Pseudomonas aeruginosa | ≤0.25 to ≥256 | ≤8 | - | ≥16 | | Ceftazidime-Avibactam | Enterobacterales | ≤0.12 to ≥64 | ≤8 | - | ≥16 | | | Pseudomonas aeruginosa | ≤0.12 to ≥64 | ≤8 | - | ≥16 | | Ceftriaxone | Enterobacterales | ≤0.25 to ≥32 | ≤1 | 2 | ≥4 | | Ciprofloxacin | Enterobacterales | ≤0.03 to ≥16 | ≤0.25 | 0.5 | ≥1 | | | Pseudomonas aeruginosa | ≤0.03 to ≥16 | ≤0.5 | 1 | ≥2 | | Ertapenem | Enterobacterales | ≤0.03 to ≥16 | ≤0.5 | 1 | ≥2 | | Gentamicin | Enterobacterales | ≤1 to ≥64 | ≤4 | 8 | ≥16 | | | Pseudomonas aeruginosa | ≤0.5 to ≥64 | ≤4 | 8 | ≥16 | | Imipenem | Acinetobacter baumannii complex | ≤0.5 to ≥64 | ≤2 | 4 | ≥8 | | | Enterobacterales | ≤0.25 to ≥64 | ≤1 | 2 | ≥4 | | Meropenem | Acinetobacter baumannii complex | ≤0.12 to ≥64 | ≤2 | 4 | ≥8 | K223493 - Page 7 of 42 {7} | Antimicrobial | Indicated Organism Group | Selux AST System Reportable Range (μg/mL) | FDA-Recognized/Approved Breakpoints * (μg/mL) | | | | --- | --- | --- | --- | --- | --- | | | | | S | I | R | | | Enterobacterales | ≤0.12 to ≥64 | ≤1 | 2 | ≥4 | | | *Pseudomonas aeruginosa* | ≤0.12 to ≥64 | ≤2 | 4 | ≥8 | | Minocycline | *Acinetobacter baumannii* complex | ≤0.25 to ≥64 | ≤4 | 8 | ≥16 | | | Enterobacterales | ≤0.25 to ≥64 | ≤4 | 8 | ≥16 | | Piperacillin-Tazobactam | *Acinetobacter baumannii* complex | ≤4 to ≥512 | ≤16 | 32-64 | ≥128 | | | Enterobacterales | ≤2 to ≥128 | ≤8 | 16 | ≥32 | | | *Pseudomonas aeruginosa* | ≤0.25 to ≥512 | ≤16 | 32-64 | ≥128 | | Tobramycin | Enterobacterales | ≤0.12 to ≥128 | ≤4 | 8 | ≥16 | | | *Pseudomonas aeruginosa* | ≤0.12 to ≥128 | ≤4 | 8 | ≥16 | S, Susceptible; I, Intermediate; R, Resistant; -, no breakpoint (interpretive criterion) recognized * FDA STIC Website https://www.fda.gov/drugs/development-resources/fda-recognized-antimicrobial-susceptibility-test-interpretive-criteria ### B Principle of Operation: See Device Description. ### C Instrument Description Information: #### 1. Instrument Name: PBC Separator with Selux AST System #### 2. Specimen Identification: Gram stain analysis is performed prior to AST testing to select the appropriate panel but is not required prior to processing with the PBC Separator. Identification (ID) using an FDA-cleared method is required prior to result interpretation and reporting after Selux AST System processing. To ensure sample traceability, the PBC Separator software associates the barcode identifier on the Inoculum Tube with the barcode identifier on the Sample Tube and transmits this information to the Selux Site Services central workstation. Refer to the K211759 Decision Summary for additional information on the Selux AST System. #### 3. Specimen (PBC) Sampling and Handling: Positive blood culture samples must be processed immediately after ringing positive on a continuous monitoring blood culture system or within 16 hours of positivity should delays be unavoidable. The user aseptically transfers 9 mL of positive blood culture from the blood bottle into the Selux Sample Tube. The user then loads the Sample Tube, Inoculum Tube, and Reagent Kit into the PBC Separator and starts the process using the graphical interface on the instrument. After processing, the inoculum tube is collected and used with the downstream Selux AST System, following the instructions for use for that system. K223493 - Page 8 of 42 {8} Refer to the K211759 Decision Summary for additional information on the Selux AST System. # 4. Calibration: The PBC Separator on-board spectrophotometer is calibrated by a trained service engineer at the time of installation. Additional weekly or as-needed calibrations should be performed by the user by following the QC workflow in the instructions for use (described below). Refer to the K211759 Decision Summary for additional information on the Selux AST System. # 5. Quality Control: Quality controls are performed to ensure that the PBC Separator works according to the intended use and performance specifications. The spectrophotometer within the PBC Separator should be calibrated weekly or as required. Following the PBC Separator Quality Control Verification procedure in the instructions for use, the user will initiate the PBC Separator QC workflow on the instrument interface. McFarland standards provided with the instrument (0.0 and 0.5 standards) are inserted into the spectrophotometer and three readings are taken, with the tube being rotated and re-inserted between each reading. The average readings for the 0.5 McFarland standard should be within the acceptable ranges defined in the instructions for use (0.44 – 0.56). The instructions for use outlines the steps to follow depending on the average readings obtained. Quality control for AST testing should be conducted in accordance with the instructions for use for the Selux AST System and Gram-Negative Panel. Refer to the Decision Summary for K211748 for additional information. # **V Substantial Equivalence Information:** # **A Predicate Device Name(s):** eQUANT System # **B Predicate 510(k) Number(s):** K231536 # **C Comparison with Predicate(s):** | Device & Predicate Device(s): | Device: K223493 | Predicate: K231536 | | --- | --- | --- | | Device Trade Name | PBC Separator with Selux AST System | eQUANT System | | General Device Characteristic Similarities | | | | Indications for Use | The PBC Separator with Selux AST System is an automated inoculum preparation system that uses lysis, centrifugation and | The eQUANT System is an automated inoculum preparation system that uses potentiometric sensing of oxidation-reduction | K223493 - Page 9 of 42 {9} | Device & Predicate Device(s): | Device: K223493 | Predicate: K231536 | | --- | --- | --- | | | 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. | potential changes due to pathogen metabolism to generate a 0.5 McFarland-equivalent suspension (the eMcFarland or eMcF) from positive blood culture samples that can be used for direct, qualitative *in vitro* susceptibility testing by the agar disk diffusion test method (Kirby-Bauer). Samples are processed directly from blood culture samples identified as positive by a continuous monitoring blood culture system and confirmed as Gram-negative rods by Gram stain. Organism identification must be confirmed by an FDA cleared device for testing from positive blood culture before processing samples on the eQUANT System. | | Indicated Antimicrobials | Amikacin Amoxicillin-Clavulanate Ampicillin Ampicillin-Sulbactam Cefazolin Cefepime Ceftazidime Ceftazidime-Avibactam Ceftriaxone Ciprofloxacin Ertapenem Gentamicin Imipenem Meropenem Minocycline Piperacillin-Tazobactam Tobramycin | Amoxicillin/clavulanate Ampicillin Aztreonam Cefazolin Cefepime Ceftriaxone Ertapenem Gentamicin Levofloxacin Meropenem Piperacillin/Tazobactam Tobramycin | | Indicated Organisms | *Acinetobacter baumannii* complex *Citrobacter freundii* complex *Citrobacter koseri* *Enterobacter cloacae* complex *Escherichia coli* *Klebsiella spp.* *Morganella morganii* | *Acinetobacter spp.* *Citrobacter freundii* *Enterobacter cloacae* *Escherichia coli* *Klebsiella aerogenes* *Klebsiella pneumoniae* *Klebsiella oxytoca* | K223493 - Page 10 of 42 {10} | Device & Predicate Device(s): | Device: **K223493** | Predicate: **K231536** | | --- | --- | --- | | | *Proteus mirabilis* *Proteus vulgaris* *Pseudomonas aeruginosa* *Serratia marcescens* | *Proteus mirabilis* *Proteus vulgaris* *Pseudomonas aeruginosa* *Serratia marcescens* | | Sample Type | Aliquot from monomicrobial positive blood culture | Same | | Output/Results Reporting | Liquid suspension (McFarland equivalent) of bacteria suitable for downstream susceptibility testing; no results reported | Same | | General Device Characteristic Differences | | | | Technology | Uses a series of lysis and centrifugation steps and sequential optical density measurements to generate a tuned McFarland equivalent inoculum. | Measure pathogen concentration via potentiometric sensing of changes in oxidation-reduction potential (ORP) during pathogen metabolism. Uses species-specific and blood culture bottle specific algorithms to determine when a 0.5 McFarland equivalent concentration is reached. | | Downstream Susceptibility Testing | Selux AST System | Kirby-Bauer Disk Diffusion | ## VI Standards/Guidance Documents Referenced: - FDA Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA (Issued August 28, 2009) - CLSI M100-Ed33. *Performance Standards for Antimicrobial Susceptibility Testing*; 33rd Edition (March 2023) ## VII Performance Characteristics (if/when applicable): ### A Analytical Performance: #### 1. Precision/Reproducibility: Reproducibility testing for the PBC Separator with Selux AST System was conducted at three testing sites (two external and one internal site). Panel members included representative species indicated for use with each respective antimicrobial. As the Selux AST System (which includes all components other than the PBC Separator) and GN Panel had previously been cleared (K211759 and K211748), a truncated panel of antimicrobial agents include at K223493 - Page 11 of 42 {11} least one representative drug from each claimed drug class was considered acceptable for testing. Reproducibility was determined from the total number (and percent) of results that fell within one dilution (+/- one doubling dilution) of the modal MIC result divided by the total number of results. Reproducibility was evaluated between sites (inter-site) and within sites (intra-site). Both best-case (assumes that off-scale results are within one dilution of the mode) and worst-case (assumes that off-scale results are more than one dilution of the mode) performance was determined for each antimicrobial, as outlined in the AST Special Controls Guidance. In the initial study, inter-site reproducibility was evaluated at three sites by testing at least five representative isolates with on-scale MIC values for each antimicrobial, for a minimum of 135 results per antimicrobial (5 isolates x 3 sites x 3 replicates x 3 days = 135 results/antimicrobial). For some antimicrobials, an additional isolate was tested as well. Both best-case and worst-case inter-site reproducibility was ≥95% and were acceptable. Since representative isolates of one of the claimed organism groups (A. baumannii) were not included in the initial reproducibility study, a supplemental study was conducted with antimicrobials analyzed in the reproducibility study that have A. baumannii complex claims (ampicillin-sulbactam, meropenem, and minocycline). Testing was performed on three instruments at a single internal site and data from all three systems were combined to assess inter-site reproducibility. Data from both studies are collated and summarized in Table 2 below. Performance is summarized for each antimicrobial tested with all organisms. Inter-site reproducibility was determined to be acceptable. Intra-site reproducibility was evaluated by testing a minimum of five representative isolates in triplicate on three days at one internal site for a minimum of 45 results per antimicrobial (5 isolates x 3 replicates x 3 days = 45 results/antimicrobial). Additional isolates were included for some antimicrobials. Best-case and worst-case intra-site reproducibility was acceptable (≥95%). As with the inter-site study, supplemental testing was conducted to analyze A. baumannii with associated antimicrobials. Data from both studies are collated and summarized in Table 2 below. Performance is summarized for each antimicrobial tested with all organisms. Inter-site reproducibility was determined to be acceptable. Table 2. Reproducibility of the PBC Separator with Selux AST System | Antimicrobial | Inter-site Reproducibility | | Intra-site Reproducibility | | | --- | --- | --- | --- | --- | | | Best-case (%) | Worst-case (%) | Best-case (%) | Worst-case (%) | | Ampicillin | 134/135 (99.3%) | 134/135 (99.3%) | 45/45 (100%) | 45/45 (100%) | | Ampicillin-sulbactam * | 162/162 (100%) | 162/162 (100%) | 54/54 (100%) | 54/54 (100%) | | Amoxicillin-clavulanate | 135/135 (100%) | 135/135 (100%) | 45/45 (100%) | 45/45 (100%) | | Cefazolin | 135/135 (100%) | 135/135 (100%) | 45/45 (100%) | 45/45 (100%) | | Ceftazidime-avibactam | 135/135 (100%) | 135/135 (100%) | 45/45 (100%) | 45/45 (100%) | | Ciprofloxacin | 162/162 (100%) | 162/162 (100%) | 54/54 (100%) | 54/54 (100%) | | Gentamicin | 160/162 (98.8%) | 160/162 (98.8%) | 54/54 (100%) | 54/54 (100%) | | Meropenem * | 181/189 (95.8%) | 181/189 (95.8%) | 62/63 (98.4%) | 62/63 (98.4%) | | Minocycline * | 156/162 (96.3%) | 156/162 (96.3%) | 53/54 (98.1%) | 53/54 (98.1%) | * In instances where a representative species from a claimed organism group was not included in the original study, supplemental testing was conducted, and data were collated with original data. K223493 - Page 12 of 42 {12} 2. Linearity: Not applicable. 3. Analytical Specificity/Interference: *Endogenous/Exogenous Interfering Substances* An interfering substances study was performed to evaluate if substances naturally present or artificially introduced into blood culture bottles affected PBC Separator with Selux AST System performance. Selux AST System MIC results from PBC Separator-prepared samples were evaluated using seeded PBC samples with and without interfering substances. Representative organisms including at least one from each organism reporting group were evaluated with each claimed antimicrobial. Endogenous and exogenous interferents were spiked into blood culture bottles at or above clinically relevant concentrations alongside bacteria. Bottles were processed with a continuous monitoring blood culture system until positivity and processed with the PBC Separator. As this is a method-to-method comparison, essential agreement (EA) of ≥95% was deemed acceptable. Performance with potential endogenous and exogenous interferents is shown in **Tables 3-5**. In general, the data were acceptable. There were a few instances in which EA was <95% for specific interferents, discussed below: *Endogenous Interferents* - Amikacin when tested with Triglycerides had an EA < 90% for *P. aeruginosa*. A single replicate was out of EA and was within category agreement (CA), and thus is not expected to impact clinical care; the data are acceptable. - Piperacillin-Tazobactam had an EA < 90% across multiple conditions. This was due to very major errors with *K. pneumoniae*. The following limitation is included in the device labeling to address these errors: - *An essential agreement <90% and very major errors were observed when testing Piperacillin-Tazobactam with K. pneumoniae with all evaluated potential interferents.* *Exogenous Interferents* - Cefepime when tested with potential interferents Cefpodoxime and Gentamicin had EA < 90% for Enterobacterales. This was due to the inclusion of one strain of *K. pneumoniae* that was out of EA; however, when data were evaluated by strains, the performance was acceptable. - Imipenem when tested with potential interferents Cefpodoxime and Gentamicin had EA < 90% for Enterobacterales. This was due to the inclusion of one strain of *K. pneumoniae* that was out of EA; however, when data were evaluated by strains, the performance was acceptable. - Tobramycin when tested with potential interferent Cefpodoxime had an EA < 90% for Enterobacterales. This was due to one isolate of *E. coli* and one isolate of *K. pneumoniae* being out of EA. The out-of-EA results were within the intermediate breakpoint category, whereas the modal control results were susceptible. However, due to the overall study data, this was deemed acceptable. K223493 - Page 13 of 42 {13} ○ An essential agreement <90% and minor errors were observed when testing Tobramycin with E. coli and K. pneumoniae with the potential interferent cefpodoxime. Table 3. Performance with potential endogenous interferents (part 1). | Antimicrobial | Indicated Organism(s) | Red Blood Cells (20 g/dL) | | White Blood Cells (12,000 cells/μL) | | Platelets (450,000/μL) | | Gamma Globulins (50 g/L) | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | | | # EA / Total | % EA | # EA / Total | % EA | # EA / Total | % EA | # EA / Total | % EA | | Amikacin | *A. baumannii* complex | 2/2 | 100.0% | 4/4 | 100.0% | 3/3 | 100.0% | 3/3 | 100.0% | | | Enterobacterales | 11/11 | 100.0% | 5/5 | 100.0% | 5/5 | 100.0% | 10/10 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 5/5 | 100.0% | 4/4 | 100.0% | 4/4 | 100.0% | | | Combined | 15/15 | 100.0% | 14/14 | 100.0% | 12/12 | 100.0% | 17/17 | 100.0% | | Amoxicillin-Clavulanate | Enterobacterales | 11/11 | 100.0% | 5/5 | 100.0% | 5/5 | 100.0% | 10/10 | 100.0% | | Ampicillin | Enterobacterales | 9/9 | 100.0% | 4/4 | 100.0% | 4/4 | 100.0% | 8/8 | 100.0% | | Ampicillin-Sulbactam | *A. baumannii* complex | /2/ | 100.0% | 4/4 | 100.0% | 5/5 | 100.0% | 4/4 | 100.0% | | | Enterobacterales | 11/11 | 100.0% | 5/5 | 100.0% | 5/5 | 100.0% | 10/10 | 100.0% | | | Combined | 13/13 | 100.0% | 9/9 | 100.0% | 10/10 | 100.0% | 14/14 | 100.0% | | Cefazolin | Enterobacterales | 11/11 | 100.0% | 5/5 | 100.0% | 5/5 | 100.0% | 10/10 | 100.0% | | Cefepime | Enterobacterales | 11/11 | 100.0% | 5/5 | 100.0% | 5/5 | 100.0% | 10/10 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 5/5 | 100.0% | 4/4 | 100.0% | 4/4 | 100.0% | | | Combined | 13/13 | 100.0% | 10/10 | 100.0% | 9/9 | 100.0% | 14/14 | 100.0% | | Ceftazidime | Enterobacterales | 11/11 | 100.0% | 5/5 | 100.0% | 5/5 | 100.0% | 10/10 | 100.0% | | | *P. aeruginosa* | 1/1 | 100.0% | 4/4 | 100.0% | 4/4 | 100.0% | 2/2 | 100.0% | | | Combined | 12/12 | 100.0% | 9/9 | 100.0% | 9/9 | 100.0% | 12/12 | 100.0% | | Ceftazidime-Avibactam | Enterobacterales | 11/11 | 100.0% | 5/5 | 100.0% | 5/5 | 100.0% | 10/10 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 5/5 | 100.0% | 4/4 | 100.0% | 4/4 | 100.0% | | | Combined | 13/13 | 100.0% | 10/10 | 100.0% | 9/9 | 100.0% | 14/14 | 100.0% | | Ceftriaxone | Enterobacterales | 11/11 | 100.0% | 5/5 | 100.0% | 5/5 | 100.0% | 10/10 | 100.0% | | Ciprofloxacin | Enterobacterales | 11/11 | 100.0% | 5/5 | 100.0% | 5/5 | 100.0% | 10/10 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 5/5 | 100.0% | 4/4 | 100.0% | 4/4 | 100.0% | | | Combined | 13/13 | 100.0% | 10/10 | 100.0% | 9/9 | 100.0% | 14/14 | 100.0% | | Ertapenem | Enterobacterales | 11/11 | 100.0% | 5/5 | 100.0% | 5/5 | 100.0% | 10/10 | 100.0% | | Gentamicin | Enterobacterales | 11/11 | 100.0% | 5/5 | 100.0% | 5/5 | 100.0% | 10/10 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 5/5 | 100.0% | 4/4 | 100.0% | 4/4 | 100.0% | | | Combined | 13/13 | 100.0% | 10/10 | 100.0% | 9/9 | 100.0% | 14/14 | 100.0% | | Imipenem | *A. baumannii* complex | 2/2 | 100.0% | 4/4 | 100.0% | 5/5 | 100.0% | 4/4 | 100.0% | | | Enterobacterales | 11/11 | 100.0% | 5/5 | 100.0% | 5/5 | 100.0% | 10/10 | 100.0% | | | Combined | 13/13 | 100.0% | 9/9 | 100.0% | 10/10 | 100.0% | 14/14 | 100.0% | | Meropenem | *A. baumannii* complex | 2/2 | 100.0% | 4/4 | 100.0% | 5/5 | 100.0% | 4/4 | 100.0% | | | Enterobacterales | 11/11 | 100.0% | 5/5 | 100.0% | 5/5 | 100.0% | 10/10 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 5/5 | 100.0% | 4/4 | 100.0% | 4/4 | 100.0% | | | Combined | 15/15 | 100.0% | 14/14 | 100.0% | 14/14 | 100.0% | 18/18 | 100.0% | | Minocycline | *A. baumannii* complex | 2/2 | 100.0% | 4/4 | 100.0% | 5/5 | 100.0% | 4/4 | 100.0% | | | Enterobacterales | 11/11 | 100.0% | 5/5 | 100.0% | 5/5 | 100.0% | 10/10 | 100.0% | | | Combined | 13/13 | 100.0% | 9/9 | 100.0% | 10/10 | 100.0% | 14/14 | 100.0% | | Piperacillin-Tazobactam | *A. baumannii* complex | 2/2 | 100.0% | 4/4 | 100.0% | 3/6 | 60.0% | 4/4 | 100.0% | | | Enterobacterales | 2/11 | 18.2% | 1/5 | 20.0% | 1/5 | 20.0% | 2/10 | 20.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 5/5 | 100.0% | 4/4 | 100.0% | 4/4 | 100.0% | | | Combined | 6/15 | 40.0% | 10/14 | 71.4% | 8/14 | 57.1% | 10/18 | 55.6% | | Tobramycin | Enterobacterales | 10/11 | 90.9% | 4/5 | 80.0% | 5/5 | 100.0% | 9/10 | 90.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 5/5 | 100.0% | 4/4 | 100.0% | 4/4 | 100.0% | | | Combined | 12/13 | 92.3% | 9/10 | 90.0% | 9/9 | 100.0% | 13/14 | 92.9% | K223493 - Page 14 of 42 {14} Table 4. Performance with potential endogenous interferents (part 2). | Antimicrobial | Indicated Organism(s) | Conjugated Bilirubin (475 μmol/L) | | Unconjugated Bilirubin (684 μmol/L) | | Triglycerides (16.94 mmol/L) | | | --- | --- | --- | --- | --- | --- | --- | --- | | | | # EA / Total | % EA | # EA / Total | % EA | # EA / Total | % EA | | Amikacin | *A. baumannii* complex | 2/2 | 100.0% | 2/2 | 100.0% | 1/1 | 100.0% | | | Enterobacterales | 11/11 | 100.0% | 11/11 | 100.0% | 7/7 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 100.0% | 2/3 | 66.7%^{1} | | | Combined | 15/15 | 100.0% | 15/15 | 100.0% | 10/11 | 100.0% | | Amoxicillin-Clavulanate | Enterobacterales | 11/11 | 100.0% | 11/11 | 100.0% | 7/7 | 100.0% | | Ampicillin | Enterobacterales | 9/9 | 100.0% | 9/9 | 100.0% | 5/5 | 100.0% | | Ampicillin-Sulbactam | *A. baumannii* complex | 2/2 | 100.0% | 2/2 | 100.0% | 3/3 | 100.0% | | | Enterobacterales | 11/11 | 100.0% | 11/11 | 100.0% | 7/7 | 100.0% | | | Combined | 13/13 | 100.0% | 13/13 | 100.0% | 10/10 | 100.0% | | Cefazolin | Enterobacterales | 11/11 | 100.0% | 11/11 | 100.0% | 7/7 | 100.0% | | Cefepime | Enterobacterales | 11/11 | 100.0% | 11/11 | 100.0% | 7/7 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 100.0% | 3/3 | 100.0% | | | Combined | 13/13 | 100.0% | 13/13 | 100.0% | 10/10 | 100.0% | | Ceftazidime | Enterobacterales | 11/11 | 100.0% | 11/11 | 100.0% | 7/7 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 1/1 | 100.0% | 3/3 | 100.0% | | | Combined | 13/13 | 100.0% | 12/12 | 100.0% | 10/10 | 100.0% | | Ceftazidime-Avibactam | Enterobacterales | 11/11 | 100.0% | 11/11 | 100.0% | 7/7 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 100.0% | 3/3 | 100.0% | | | Combined | 13/13 | 100.0% | 13/13 | 100.0% | 10/10 | 100.0% | | Ceftriaxone | Enterobacterales | 11/11 | 100.0% | 11/11 | 100.0% | 7/7 | 100.0% | | Ciprofloxacin | Enterobacterales | 11/11 | 100.0% | 11/11 | 100.0% | 7/7 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 100.0% | 3/3 | 100.0% | | | Combined | 13/13 | 100.0% | 13/13 | 100.0% | 10/10 | 100.0% | | Ertapenem | Enterobacterales | 11/11 | 100.0% | 11/11 | 100.0% | 7/7 | 100.0% | | Gentamicin | Enterobacterales | 11/11 | 100.0% | 11/11 | 100.0% | 7/7 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 100.0% | 3/3 | 100.0% | | | Combined | 13/13 | 100.0% | 13/13 | 100.0% | 10/10 | 100.0% | | Imipenem | *A. baumannii* complex | 2/2 | 100.0% | 2/2 | 100.0% | 3/3 | 100.0% | | | Enterobacterales | 11/11 | 100.0% | 11/11 | 100.0% | 7/7 | 100.0% | | | Combined | 13/13 | 100.0% | 13/13 | 100.0% | 10/10 | 100.0% | | Meropenem | *A. baumannii* complex | 2/2 | 100.0% | 2/2 | 100.0% | 3/3 | 100.0% | | | Enterobacterales | 11/11 | 100.0% | 11/11 | 100.0% | 7/7 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 100.0% | 3/3 | 100.0% | | | Combined | 15/15 | 100.0% | 15/15 | 100.0% | 13/13 | 100.0% | | Minocycline | *A. baumannii* complex | 2/2 | 100.0% | 2/2 | 100.0% | 3/3 | 100.0% | | | Enterobacterales | 11/11 | 100.0% | 11/11 | 100.0% | 7/7 | 100.0% | | | Combined | 13/13 | 100.0% | 13/13 | 100.0% | 10/10 | 100.0% | | Piperacillin-Tazobactam | *A. baumannii* complex | 2/2 | 100.0% | 2/2 | 100.0% | 2/3 | 66.7% | | | Enterobacterales | 3/11 | 27.3% | 2/11 | 18.2% | 2/7 | 28.6% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 100.0% | 3/3 | 100.0% | | | Combined | 7/15 | 46.7% | 6/15 | 40.0% | 7/13 | 58.3% | | Tobramycin | Enterobacterales | 10/11 | 90.9% | 10/11 | 90.9% | 6/7 | 85.7% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 100.0% | 3/3 | 100.0% | | | Combined | 12/13 | 92.3% | 12/13 | 92.3% | 9/10 | 90.0% | $^{1}$ A single replicate was out of EA and was within CA, and thus is not expected to impact clinical care; the data are acceptable K223493 - Page 15 of 42 {15} Table 5. Performance with potential exogenous interferents. | Antimicrobial | Indicated Organism(s) | Cefpodoxime (2.3 μg/mL) | | Ciprofloxacin (3.6 μg/mL) | | Gentamicin (24 μg/mL) | | Penicillin (6.0 μg/mL) | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | | | # EA / Total | % EA | # EA / Total | % EA | # EA / Total | % EA | # EA / Total | % EA | | Amikacin | *A. baumannii* complex | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | | | Enterobacterales | 9/9 | 100.0% | 10/10 | 100.0% | 10/10 | 100.0% | 10/11 | 90.9% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | | | Combined | 13/13 | 100.0% | 14/14 | 100.0% | 14/14 | 100.0% | 14/15 | 93.3% | | Amoxicillin-Clavulanate | Enterobacterales | 9/9 | 100.0% | 10/10 | 100.0% | 10/10 | 100.0% | 10/11 | 90.9% | | Ampicillin | Enterobacterales | 7/7 | 100.0% | 8/8 | 100.0% | 8/8 | 100.0% | 9/9 | 100.0% | | Ampicillin-Sulbactam | *A. baumannii* complex | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | | | Enterobacterales | 9/9 | 100.0% | 10/10 | 100.0% | 10/10 | 100.0% | 11/11 | 100.0% | | | Combined | 11/11 | 100.0% | 12/12 | 100.0% | 12/12 | 100.0% | 13/13 | 100.0% | | Cefazolin | Enterobacterales | 9/9 | 100.0% | 10/10 | 100.0% | 10/10 | 100.0% | 11/11 | 100.0% | | Cefepime | Enterobacterales | 7/9 | 77.8% | 9/10 | 90.0% | 8/10 | 80.0% | 11/11 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | | | Combined | 9/11 | 81.8% | 11/12 | 91.7% | 10/12 | 83.3% | 13/13 | 100.0% | | Ceftazidime | Enterobacterales | 9/9 | 100.0% | 10/10 | 100.0% | 10/10 | 100.0% | 11/11 | 100.0% | | | *P. aeruginosa* | 0/0 | N/A^{1} | 0/0 | N/A^{1} | 1/1 | 100.0% | 1/1 | 100.0% | | | Combined | 9/9 | 100.0% | 10/10 | 100.0% | 11/11 | 100.0% | 12/12 | 100.0% | | Ceftazidime-Avibactam | Enterobacterales | 9/9 | 100.0% | 10/10 | 100.0% | 10/10 | 100.0% | 10/11 | 90.9% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | | | Combined | 11/11 | 100.0% | 12/12 | 100.0% | 12/12 | 100.0% | 12/13 | 92.3% | | Ceftriaxone | Enterobacterales | 9/9 | 100.0% | 10/10 | 100.0% | 10/10 | 100.0% | 11/11 | 100.0% | | Ciprofloxacin | Enterobacterales | 9/9 | 100.0% | 10/10 | 100.0% | 10/10 | 100.0% | 11/11 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | | | Combined | 11/11 | 100.0% | 12/12 | 100.0% | 12/12 | 100.0% | 13/13 | 100.0% | | Ertapenem | Enterobacterales | 9/9 | 100.0% | 10/10 | 100.0% | 10/10 | 100.0% | 11/11 | 100.0% | | Gentamicin | Enterobacterales | 9/9 | 100.0% | 10/10 | 100.0% | 10/10 | 100.0% | 11/11 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | | | Combined | 11/11 | 100.0% | 12/12 | 100.0% | 12/12 | 100.0% | 13/13 | 100.0% | | Imipenem | *A. baumannii* complex | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | | | Enterobacterales | 5/9 | 55.6% | 9/10 | 90.0% | 7/10 | 70.0% | 11/11 | 100.0% | | | Combined | 7/11 | 63.6% | 11/12 | 91.7% | 9/12 | 75.0% | 13/13 | 100.0% | | Meropenem | *A. baumannii* complex | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | | | Enterobacterales | 9/9 | 100.0% | 10/10 | 100.0% | 10/10 | 100.0% | 11/11 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | | | Combined | 13/13 | 100.0% | 14/14 | 100.0% | 14/14 | 100.0% | 15/15 | 100.0% | | Minocycline | *A. baumannii* complex | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | | | Enterobacterales | 8/9 | 88.9% | 10/10 | 100.0% | 10/10 | 100.0% | 11/11 | 100.0% | | | Combined | 11/11 | 100.0% | 12/12 | 100.0% | 12/12 | 100.0% | 13/13 | 100.0% | | Piperacillin-Tazobactam | *A. baumannii* complex | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | | | Enterobacterales | 9/9 | 100.0% | 10/10 | 90.0% | 10/10 | 100.0% | 11/11 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | 2/2 | 100.0% | | | Combined | 13/13 | 100.0% | 14/14 | 91.7% | 14/14 | 100.0% | 15/15 | 100.0% | | Tobramycin | Enterobacterales | 7/9 | 77.8% | 10/10 | 100.0% | 10/10 | 100.0% | 11/11 | 100.0% | | | *P. aeruginosa* | 2/2 | 100.0% | 2/2 | 97.0% | 2/2 | 100.0% | 2/2 | 100.0% | | | Combined | 9/11 | 81.8% | 12/12 | 100.0% | 12/12 | 100.0% | 13/13 | 100.0% | $^{1}$ Due to an error, results were not available in the control condition # 4. Assay Reportable Range: Not applicable. K223493 - Page 16 of 42 {16} # 5. Traceability, Stability, Expected Values (Controls, Calibrators, or Methods): **Quality Control Testing.** Quality control testing was performed each day that testing was conducted. Clinical sites conducted daily QC of the PBC Separator by measuring a 0.5 McFarland standard inoculum on each instrument in use, according to the PBC Separator instructions for use. During QC testing across all four clinical testing sites, triplicate OD readings of the 0.5 McFarland standard were averaged and compared to the acceptable range (0.44-0.56). The PBC Separator QC readings were within the expected OD range for 100% of the measurements. Selux AST System QC was conducted in accordance with the instructions for use with the Gran-Negative Panel. An additional QC study was conducted to verify the QC of the PBC Separator with Selux AST System as a whole. In this study, three CLSI-recommended ATCC QC strains (*E. coli* ATCC 25922, *K. pneumoniae* ATCC 700603, and *P. aeruginosa* ATCC 27853) were seeded in blood culture bottles, incubated until positivity, and processed with the PBC Separator. Inoculums were used with the Gram-Negative Panel on the Selux AST System. Testing was conducted at three sites (two external, one internal). Performance was evaluated as the frequency with which test results were within the expected QC MIC range for each antimicrobial at each site. All antimicrobials demonstrated ≥95% of samples within the acceptable QC range at each site and cumulatively. The data is presented in **Table 6** and all results were within the expected range. **Table 6.** Performance of the PBC Separator with Selux AST System using QC strains seeded into blood culture bottles | Antimicrobial | QC Strain | Selux Dilution Range | Acceptable QC Range | Site 1 | | Site 2 | | Site 3 | | All Sites | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | | | | | N | % in Range | N | % in Range | N | % in Range | N | % in Range | | Amikacin | *P. aeruginosa* ATCC 27853 | ≤0.12 to ≥256 | 1-4 µg/mL | 20 | 100 | 27 | 100 | 25 | 100 | 72 | 100 | | Amoxicillin clavulanate | *K. pneumoniae* ATCC 700603 | ≤0.5 to ≥128 | 4-16 µg/mL | 22 | 100 | 28 | 100 | 23 | 100 | 73 | 100 | | Ampicillin | *E. coli* ATCC 25922 | ≤0.25 to ≥128 | 2-8 µg/mL | 15 | 100 | 29 | 100 | 21 | 100 | 65 | 100 | | Ampicillin-sulbactam | *K. pneumoniae* ATCC 700603 | ≤0.5 to ≥128 | 8-32 µg/mL | 22 | 100 | 28 | 96.4 | 23 | 100 | 73 | 98.6 | | Cefazolin | *E. coli* ATCC 25922 | ≤0.12 to ≥128 | 1-4 µg/mL | 15 | 100 | 29 | 100 | 21 | 100 | 65 | 100 | | Cefepime | *P. aeruginosa* ATCC 27853 | ≤0.25 to ≥128 | 0.5-4 µg/mL | 20 | 100 | 27 | 100 | 25 | 100 | 72 | 100 | | Ceftazidime | *P. aeruginosa* ATCC 27853 | ≤0.25 to ≥256 | 1-4 µg/mL | 20 | 100 | 27 | 96.3 | 25 | 100 | 72 | 98.6 | | Ceftazidime-avibactam | *K. pneumoniae* ATCC 700603 | ≤0.12 to ≥64 | 0.25-2 µg/mL | 22 | 100 | 28 | 100 | 23 | 100 | 73 | 100 | | Ciprofloxacin | *P. aeruginosa* ATCC 27853 | ≤0.03 to ≥16 | 0.12-1 µg/mL | 20 | 100 | 27 | 100 | 25 | 100 | 72 | 100 | | Gentamicin | *E. coli* ATCC 25922 | ≤0.06 to ≥64 | 0.25-1 µg/mL | 15 | 100 | 27 | 100 | 21 | 100 | 63 | 100 | | Imipenem | *K. pneumoniae* ATCC 700603 | ≤0.016 to ≥64 | 0.06-0.5 µg/mL | 22 | 100 | 28 | 100 | 23 | 95.7 | 73 | 98.6 | K223493 - Page 17 of 42 {17} | Antimicrobial | QC Strain | Selux Dilution Range | Acceptable QC Range | Site 1 | | Site 2 | | Site 3 | | All Sites | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | | | | | N | % in Range | N | % in Range | N | % in Range | N | % in Range | | Meropenem | *P. aeruginosa* ATCC 27853 | ≤0.12 to ≥64 | 0.12-1 µg/mL^{1} | 20 | 100 | 27 | 96.3 | 25 | 100 | 72 | 98.6 | | Minocycline | *E. coli* ATCC 25922 | ≤0.25 to ≥64 | 0.25-1 µg/mL^{2} | 15 | 100 | 27 | 100 | 21 | 95.2 | 63 | 98.4 | | Piperacillin-tazobactam | *K. pneumoniae* ATCC 700603 | ≤0.25 to ≥512 | 8-32 µg/mL | 22 | 100 | 28 | 100 | 22 | 100 | 72 | 100 | | Tobramycin | *P. aeruginosa* ATCC 27853 | ≤0.12 to ≥128 | 0.25-1 µg/mL | 20 | 100 | 27 | 100 | 25 | 100 | 72 | 100 | $^{1}$ The dilution 0.12 µg/mL is off-scale for Meropenem on the Selux AST System $^{2}$ The dilution 0.25 µg/mL is off-scale for Minocycline on the Selux AST System The user is not instructed to perform QC testing with seeded blood culture bottles. Instead, the user should conduct QC for the PBC Separator and Selux AST System according to their respective instructions for use. ### Positive Blood Culture Stability The sponsor conducted testing to establish the stability of positive blood culture for use with the PBC Separator with Selux AST System. Blood bottles were seeded with human blood and representative isolates (including at least one from each claimed antimicrobial reporting group) and incubated to positivity on a continuous monitoring blood culture system (bioMérieux BACT/ALERT VIRUTO or BD BACTEC). After positivity, blood bottles were processed with the PBC Separator either immediately (0 h, baseline) or after being removed from the continuous monitoring system and being stored at room temperature for 16 hours. MIC results were generated using PBC Separator-prepared inoculums with the Selux AST System. Results at the 16-hour timepoint (t=16) were compared to modal MIC results at baseline (t=0) for each drug and organism reporting group. As this was a method-to-method comparison, EA ≥95% for each antimicrobial agent was considered acceptable. The data showed no observable effects on EA with the PBC Separator with Selux AST System when testing was conducted up to 16 hours after the bottle rang positive. All antimicrobial agents demonstrated >95% EA at the 16-hour timepoint. As noted in the instructions for use, all blood culture bottle samples should be tested promptly after ringing positive on a continuous monitoring system. In the case of unavoidable delays or if the need for re-testing arises, positive blood culture bottles may be tested up to 16 hours post ring. ### Inoculum Density Check The PBC Separator has an onboard densitometer and liquid handler that prepares tuned inoculums for AST. Daily QC testing of the PBC Separator at clinical sites was done to verify that the onboard densitometer was able to consistently detect an 0.5 McFarland inoculum (see Quality Control Testing above) and results were acceptable. To further verify the microorganism turbidity, quantitative culture was performed to determine the inoculum densities of all samples in the QC analytical study, all samples in the reproducibility study other than *A. baumannii* samples, and at least 10% of clinical isolates. Data were provided as CFU/mL at the final dilution used in the wells of the Selux AST Panel, in accordance with the AST Special Controls Guidance, which is an additional 200-fold dilution factor from the final prepared suspension. The microorganism concentrations for inoculums prepared by the PBC Separator ranged from 5.0 x 10$^{5}$ CFU/mL to 1.9 x 10$^{6}$ K223493 - Page 18 of 42 {18} CFU/mL. When adjusted, this correlates to $1.0 \times 10^8$ CFU/mL to $3.8 \times 10^8$ CFU/mL, which is within the expected range (when considering an 0.5 McFarland contains approximately $1-2 \times 10^8$ CFU/mL for *E. coli* $\pm 0.6$ log difference, and the PBC Separator prepares inoculums to 0.65-0.8). The data are shown in **Table 7**. **Table 7.** Concentrations of Inoculums prepared by the PBC Separator | Organism | Study Source | Number Tested | Sample Well Concentration (CFU/mL) | | | | | --- | --- | --- | --- | --- | --- | --- | | | | | Mean | Min | Max | Std. Dev. | | *A. baumannii* complex | Clinical | 17 | 4.5E+05 | 1.2E+05 | 9.9E+05 | 2.29E+05 | | *C. freundii* complex | Clinical | 7 | 7.3E+05 | 2.2E+05 | 1.2E+06 | 3.68E+05 | | *C. koseri* | Clinical | 8 | 1.1E+06 | 4.1E+05 | 1.9E+06 | 4.74E+05 | | *E. coli* | Reproducibility, Clinical | 275 | 5.1E+05 | 3.0E+04 | 1.5E+06 | 2.10E+05 | | *K. aerogenes* | Clinical | 9 | 8.2E+05 | 2.5E+05 | 1.7E+06 | 5.40E+05 | | *K. oxytoca* | Clinical | 9 | 6.0E+05 | 2.5E+05 | 1.4E+06 | 3.88E+05 | | *K. pneumoniae* | Reproducibility, Clinical | 209 | 4.3E+05 | 6.0E+04 | 1.2E+06 | 1.86E+05 | | *M. morganii* | Clinical | 5 | 6.1E+05 | 1.1E+05 | 1.5E+06 | 5.10E+05 | | *P. aeruginosa* | Reproducibility, Clinical | 10 | 7.3E+05 | 2.0E+05 | 1.1E+06 | 2.86E+05 | | *P. mirabilis* | Clinical | 5 | 6.4E+05 | 5.0E+03 | 1.2E+06 | 4.57E+05 | | *P. vulgaris* | Clinical | 17 | 5.3E+05 | 2.3E+05 | 9.5E+05 | 2.23E+05 | | *S. marcescens* | Clinical | 6 | 6.5E+05 | 2.1E+05 | 1.3E+06 | 4.37E+05 | **Device Failure.** The PBC Separator is equipped with self-checking mechanisms to identify run errors. There were nine instrument failures observed during the original and supplemental testing. All were detected at the time of failure by the instrument and resulted in excluded samples. **Purity Check.** Purity plates were prepared from the inoculum suspensions of every sample tested. AST results were only reported for pure isolates; data generated from plates that generated multiple colony morphologies was excluded from analyses. # 6. Detection Limit: Not applicable. # 7. Assay Cut-Off: Not applicable. # 8. Accuracy (Instrument): Not applicable. K223493 - Page 19 of 42 {19} ## 9. Carry-Over: The purpose of this study was to evaluate the potential for carry-over of samples prepared with the PBC separator. The PBC Separator instructions for use were followed to prepare samples of *E. coli* and *K. pneumoniae* during repeated runs. One replicate of *E. coli* and one replicate of *K. pneumoniae*, which were selected to have different AST profiles, were processed at the same time through a single PBC Separator with Selux AST System. A total of five runs were conducted, with each run containing one *E. coli* sample and one *K. pneumoniae* sample. Purity plates were prepared from the inoculums prepared by the PBC Separator. The MIC results from the Selux AST testing were compared to reference results. Performance was evaluated by reviewing purity plates and AST results. Performance was acceptable if there was zero purity plate contamination caused by the other species and >90% essential agreement (EA) compared with BMD reference results. The purity plates did not show evidence of carry-over between *E. coli* and *K. pneumoniae* (i.e., single morphology colonies on each representative plate). MIC results from each species demonstrated >90% EA to the reference result. Additionally, the system did not report any faults due to high background or viability contamination. The data are acceptable. Cross-contamination and carry-over with the Inoculator and Analyzer components of the Selux AST System was previously assessed and deemed acceptable in K211759. ## **B Comparison Studies:** ### 1. Method Comparison with Reference: Clinical performance testing was conducted with the PBC Separator with Selux AST System. Performance was evaluated using fresh positive blood culture (PBC) samples, PBC samples seeded with contemporary and stock clinical isolates, as well as PBC samples seeded with challenge isolates selected for their resistance profiles. Contemporary isolates were defined as isolates that had been collected and frozen and tested within six months of collection while stock isolates were tested six or more months after collection. Clinical isolates were collected from positive blood culture bottles confirmed to have gram negative bacteria by Gram stain at two clinical sites within the U.S. and testing was conducted at four sites (3 external, 1 internal). A total of 469 clinical (162 fresh and 307 stock) and 87 challenge isolates from 12 different Enterobacterales species, *Acinetobacter baumannii* complex, and *Pseudomonas aeruginosa* were tested to evaluate the PBC Separator with Selux AST System performance for 17 antimicrobials. The number of datapoints for the various antimicrobial-organisms tested varied depending on the spectrum of activity, breakpoints, and the claimed organisms (species/group) for each antimicrobial on the panel. Datapoints ranged from 38 (e.g., Amikacin/*A. baumannii*) to 469 (e.g., Ciprofloxacin/Enterobacterales). Selux AST System MIC results from PBC Separator-prepared samples were compared to the modal value of triplicate broth microdilution reference results performed at an independent reference laboratory. Performance was determined generally based on criteria outlined in the Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems including K223493 - Page 20 of 42 {20} essential agreement (EA), categorical agreement (CA), and categorical errors (minor, major and very major errors). EA was calculated as the percentage of Selux MIC results that were within plus or minus one serial two-fold dilution of the reference result. CA was calculated as the percentage of Selux interpretive results (S/I/R) that were identical to the interpretive results of the reference result. EA of evaluable results (on-scale Selux and reference results or results in which an off-scale result was at least two doubling dilutions from the on-scale result) were also calculated. Performance was considered acceptable if the EA and CA were ≥90%, major error rate was ≤3%, and very major error rate was ≤2%. A high-level summary of the PBC Separator with Selux AST System performance is described below for each antimicrobial and indicated species. Complete details and results including EA, CA and error rate analyses are summarized in Table 8 and trending analyses are summarized in Table 9. Details of the performance for each drug/organism combination are provided below Table 8. Table 8. PBC Separator with Selux AST System performance | | Tot | No. EA | EA % | Eval EA Tot | No. Eval EA | Eval EA % | No. CA | CA % | No. R or NS | No. S | min | maj | vmj | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | **Amikacin – Acinetobacter baumannii complex** [Breakpoints (μg/mL): 16 (S), 32 (I), 64 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 10 | 10 | 100 | 4 | 4 | 100 | 9 | 90 | 7 | 2 | 1 | 0 | 0 | | Fresh | 1 | 1 | 100 | 0 | 0 | NA | 1 | 100 | 1 | 0 | 0 | 0 | 0 | | Clinical Seeded | 27 | 24 | 88.89 | 19 | 16 | 84.21 | 26 | 96.3 | 9 | 16 | 1 | 0 | 0 | | Combined | 38 | 35 | 92.11 | 23 | 20 | 86.96 | 36 | 94.74 | 17 | 18 | 2 | 0 | 0 | | **Amikacin – Enterobacterales** [Breakpoints (μg/mL): 16 (S), 32 (I), 64 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 56 | 54 | 96.43 | 9 | 7 | 77.78 | 53 | 94.64 | 7 | 45 | 3 | 0 | 0 | | Fresh | 98 | 94 | 95.92 | 16 | 12 | 75 | 98 | 100 | 0 | 98 | 0 | 0 | 0 | | Clinical Seeded | 62 | 60 | 96.77 | 4 | 2 | 50 | 62 | 100 | 1 | 60 | 0 | 0 | 0 | | Combined | 216 | 208 | 96.3 | 29 | 21 | 72.41 | 213 | 98.61 | 8 | 203 | 3 | 0 | 0 | | **Amikacin – Pseudomonas aeruginosa** [Breakpoints (μg/mL): 16 (S), 32 (I), 64 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 16 | 15 | 93.75 | 15 | 14 | 93.33 | 13 | 81.25 | 6 | 10 | 3 | 0 | 0 | | Fresh | 13 | 13 | 100 | 13 | 13 | 100 | 13 | 100 | 0 | 12 | 0 | 0 | 0 | | Clinical Seeded | 15 | 14 | 93.33 | 15 | 14 | 93.33 | 14 | 93.33 | 0 | 14 | 1 | 0 | 0 | | Combined | 44 | 42 | 95.45 | 43 | 41 | 95.35 | 40 | 90.91 | 6 | 36 | 4 | 0 | 0 | | **Amoxicillin-Clavulanate – Enterobacterales** [Breakpoints (μg/mL): 8 (S), 16 (I), 32 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 56 | 56 | 100 | 45 | 45 | 100 | 49 | 87.5 | 19 | 23 | 7 | 0 | 0 | | Fresh | 134 | 134 | 100 | 97 | 97 | 100 | 120 | 89.55 | 2 | 114 | 14 | 0 | 0 | | Clinical Seeded | 140 | 138 | 98.57 | 80 | 78 | 97.5 | 126 | 90 | 18 | 103 | 14 | 0 | 0 | | Combined | 330 | 328 | 99.39 | 222 | 220 | 99.1 | 295 | 89.39 | 39 | 240 | 35 | 0 | 0 | | **Ampicillin – Enterobacterales** [Breakpoints (μg/mL): 8 (S), 16 (I), 32 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 28 | 28 | 100 | 0 | 0 | NA | 28 | 100 | 27 | 1 | 0 | 0 | 0 | | Fresh | 74 | 73 | 98.65 | 2 | 1 | 50 | 73 | 98.65 | 49 | 24 | 1 | 0 | 0 | K223493 - Page 21 of 42 {21} | | Tot | No. EA | EA % | Eval EA Tot | No. Eval EA | Eval EA % | No. CA | CA % | No. R or NS | No. S | min | maj | vmj | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | Clinical Seeded | 47 | 47 | 100 | 2 | 2 | 100 | 47 | 100 | 20 | 27 | 0 | 0 | 0 | | Combined | 149 | 148 | 99.33 | 4 | 3 | 75 | 148 | 99.33 | 96 | 52 | 1 | 0 | 0 | | **Ampicillin-Sulbactam – *Acinetobacter baumannii* complex [Breakpoints (µg/mL): 8 (S), 16 (I), 32 (R)]** | | | | | | | | | | | | | | | Challenge Seeded | 10 | 10 | 100 | 9 | 9 | 100 | 10 | 100 | 10 | 0 | 0 | 0 | 0 | | Fresh | 3 | 1 | 33.33 | 2 | 0 | 0 | 3 | 100 | 3 | 0 | 0 | 0 | 0 | | Clinical Seeded | 27 | 26 | 96.3 | 11 | 10 | 90.91 | 25 | 92.59 | 12 | 14 | 2 | 0 | 0 | | Combined | 40 | 37 | 92.5 | 22 | 19 | 86.36 | 38 | 95 | 25 | 14 | 2 | 0 | 0 | | **Ampicillin-Sulbactam – Enterobacterales [Breakpoints (µg/mL): 8 (S), 16 (I), 32 (R)]^{1}** | | | | | | | | | | | | | | | Challenge Seeded | 58 | 58 | 100 | 37 | 37 | 100 | 55 | 94.83 | 45 | 4 | 3 | 0 | 0 | | Fresh | 136 | 135 | 99.26 | 131 | 130 | 99.24 | 115 | 84.56 | 26 | 78 | 21 | 0 | 0 | | Clinical Seeded | 158 | 154 | 97.47 | 135 | 131 | 97.04 | 136 | 86.08 | 64 | 82 | 22 | 0 | 0 | | Combined | 352 | 347 | 98.58 | 303 | 298 | 98.35 | 306 | 86.93 | 135 | 164 | 46 | 0 | 0 | | **Cefazolin – Enterobacterales [Breakpoints (µg/mL): 2 (S), 4 (I), 8 (R)]^{2}** | | | | | | | | | | | | | | | Challenge Seeded | 51 | 51 | 100 | 3 | 3 | 100 | 49 | 96.08 | 48 | 1 | 2 | 0 | 0 | | Fresh | 95 | 90 | 94.74 | 70 | 65 | 92.86 | 84 | 88.42 | 32 | 56 | 11 | 0 | 0 | | Clinical Seeded | 61 | 56 | 91.8 | 45 | 40 | 88.89 | 54 | 88.52 | 19 | 36 | 6 | 0 | 1 | | Combined | 207 | 197 | 95.17 | 118 | 108 | 91.53 | 187 | 90.34 | 99 | 93 | 19 | 0 | 1 | | **Cefepime – Enterobacterales [Breakpoints (µg/mL): 2 (S), 4-8 (I), 16 (R)]** | | | | | | | | | | | | | | | Challenge Seeded | 48 | 46 | 95.83 | 13 | 11 | 84.62 | 44 | 91.67 | 27 | 15 | 4 | 0 | 0 | | Fresh | 118 | 113 | 95.76 | 11 | 6 | 54.55 | 113 | 95.76 | 16 | 95 | 5 | 0 | 0 | | Clinical Seeded | 240 | 237 | 98.75 | 13 | 10 | 76.92 | 233 | 97.08 | 18 | 219 | 7 | 0 | 0 | | Combined | 406 | 396 | 97.54 | 37 | 27 | 72.97 | 390 | 96.06 | 61 | 329 | 16 | 0 | 0 | | **Cefepime – *Pseudomonas aeruginosa* [Breakpoints (µg/mL): 8 (S), 16 (R)]** | | | | | | | | | | | | | | | Challenge Seeded | 16 | 16 | 100 | 11 | 11 | 100 | 16 | 100 | 8 | 8 | 0 | 0 | 0 | | Fresh | 12 | 12 | 100 | 12 | 12 | 100 | 12 | 100 | 1 | 11 | 0 | 0 | 0 | | Clinical Seeded | 15 | 14 | 93.33 | 14 | 13 | 92.86 | 14 | 93.33 | 2 | 13 | 0 | 1 | 0 | | Combined | 43 | 42 | 97.67 | 37 | 36 | 97.3 | 42 | 97.67 | 11 | 32 | 0 | 1 | 0 | | **Ceftazidime – Enterobacterales [Breakpoints (µg/mL): 4 (S), 8 (I), 16 (R)]** | | | | | | | | | | | | | | | Challenge Seeded | 57 | 57 | 100 | 25 | 25 | 100 | 51 | 89.47 | 37 | 17 | 6 | 0 | 0 | | Fresh | 98 | 96 | 97.96 | 30 | 28 | 93.33 | 91 | 92.86 | 20 | 77 | 7 | 0 | 0 | | Clinical Seeded | 62 | 62 | 100 | 12 | 12 | 100 | 62 | 100 | 13 | 46 | 0 | 0 | 0 | | Combined | 217 | 215 | 99.08 | 67 | 65 | 97.01 | 204 | 94.01 | 70 | 140 | 13 | 0 | 0 | | **Ceftazidime – *Pseudomonas aeruginosa* [Breakpoints (µg/mL): 8 (S), 16 (R)]** | | | | | | | | | | | | | | | Challenge Seeded | 16 | 16 | 100 | 12 | 12 | 100 | 16 | 100 | 8 | 8 | 0 | 0 | 0 | | Fresh | 10 | 10 | 100 | 10 | 10 | 100 | 10 | 100 | 0 | 10 | 0 | 0 | 0 | | Clinical Seeded | 14 | 14 | 100 | 13 | 13 | 100 | 14 | 100 | 1 | 13 | 0 | 0 | 0 | | Combined | 40 | 40 | 100 | 35 | 35 | 100 | 40 | 100 | 9 | 31 | 0 | 0 | 0 | | **Ceftazidime-Avibactam – Enterobacterales [Breakpoints (µg/mL): 8 (S), 16 (R)]** | | | | | | | | | | | | | | K223493 - Page 22 of 42 {22} | | Tot | No. EA | EA % | Eval EA Tot | No. Eval EA | Eval EA % | No. CA | CA % | No. R or NS | No. S | min | maj | vmj | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | Challenge Seeded | 60 | 58 | 96.67 | 22 | 20 | 90.91 | 60 | 100 | 3 | 57 | 0 | 0 | 0 | | Fresh | 118 | 116 | 98.31 | 9 | 7 | 77.78 | 118 | 100 | 0 | 118 | 0 | 0 | 0 | | Clinical Seeded | 240 | 235 | 97.92 | 65 | 60 | 92.31 | 240 | 100 | 1 | 239 | 0 | 0 | 0 | | Combined | 418 | 409 | 97.85 | 96 | 87 | 90.62 | 418 | 100 | 4 | 414 | 0 | 0 | 0 | | **Ceftazidime-Avibactam – Pseudomonas aeruginosa** [Breakpoints (µg/mL): 8 (S), 16 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 16 | 16 | 100 | 13 | 13 | 100 | 15 | 93.75 | 8 | 8 | 0 | 0 | 1 | | Fresh | 12 | 12 | 100 | 12 | 12 | 100 | 12 | 100 | 0 | 12 | 0 | 0 | 0 | | Clinical Seeded | 15 | 15 | 100 | 14 | 14 | 100 | 15 | 100 | 1 | 14 | 0 | 0 | 0 | | Combined | 43 | 43 | 100 | 39 | 39 | 100 | 42 | 97.67 | 9 | 34 | 0 | 0 | 1 | | **Ceftriaxone – Enterobacterales** [Breakpoints (µg/mL): 1 (S), 2 (I), 4 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 61 | 61 | 100 | 2 | 2 | 100 | 61 | 100 | 51 | 10 | 0 | 0 | 0 | | Fresh | 116 | 115 | 99.14 | 1 | 0 | 0 | 115 | 99.14 | 26 | 90 | 0 | 1 | 0 | | Clinical Seeded | 196 | 194 | 98.98 | 15 | 13 | 86.67 | 194 | 98.98 | 34 | 161 | 2 | 0 | 0 | | Combined | 373 | 370 | 99.2 | 18 | 15 | 83.33 | 370 | 99.2 | 111 | 261 | 2 | 1 | 0 | | **Ciprofloxacin – Enterobacterales** [Breakpoints (µg/mL): 0.25 (S), 0.5 (I), 1 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 60 | 59 | 98.33 | 15 | 14 | 93.33 | 57 | 95 | 43 | 17 | 3 | 0 | 0 | | Fresh | 145 | 141 | 97.24 | 25 | 21 | 84 | 140 | 96.55 | 36 | 106 | 4 | 1 | 0 | | Clinical Seeded | 264 | 261 | 98.86 | 42 | 39 | 92.86 | 260 | 98.48 | 38 | 223 | 4 | 0 | 0 | | Combined | 469 | 461 | 98.29 | 82 | 74 | 90.24 | 457 | 97.44 | 117 | 346 | 11 | 1 | 0 | | **Ciprofloxacin – Pseudomonas aeruginosa** [Breakpoints (µg/mL): 0.5 (S), 1 (I), 2 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 16 | 16 | 100 | 8 | 8 | 100 | 16 | 100 | 11 | 5 | 0 | 0 | 0 | | Fresh | 12 | 12 | 100 | 10 | 10 | 100 | 11 | 91.67 | 1 | 11 | 1 | 0 | 0 | | Clinical Seeded | 15 | 15 | 100 | 14 | 14 | 100 | 15 | 100 | 1 | 13 | 0 | 0 | 0 | | Combined | 43 | 43 | 100 | 32 | 32 | 100 | 42 | 97.67 | 13 | 29 | 1 | 0 | 0 | | **Ertapenem – Enterobacterales** [Breakpoints (µg/mL): 0.5 (S), 1 (I), 2 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 59 | 57 | 96.61 | 15 | 13 | 86.67 | 58 | 98.31 | 17 | 41 | 1 | 0 | 0 | | Fresh | 117 | 116 | 99.15 | 12 | 11 | 91.67 | 116 | 99.15 | 1 | 115 | 1 | 0 | 0 | | Clinical Seeded | 236 | 232 | 98.31 | 35 | 31 | 88.57 | 234 | 99.15 | 10 | 223 | 2 | 0 | 0 | | Combined | 412 | 405 | 98.3 | 62 | 55 | 88.71 | 408 | 99.03 | 28 | 379 | 4 | 0 | 0 | | **Gentamicin – Enterobacterales** [Breakpoints (µg/mL): 4 (S), 8 (I), 16 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 59 | 55 | 93.22 | 16 | 12 | 75 | 56 | 94.92 | 28 | 29 | 3 | 0 | 0 | | Fresh | 142 | 140 | 98.59 | 13 | 11 | 84.62 | 140 | 98.59 | 20 | 121 | 1 | 1 | 0 | | Clinical Seeded | 264 | 263 | 99.62 | 8 | 7 | 87.5 | 262 | 99.24 | 16 | 247 | 2 | 0 | 0 | | Combined | 466 | 459 | 98.5 | 37 | 30 | 81.08 | 459 | 98.5 | 64 | 398 | 6 | 1 | 0 | | **Gentamicin – Pseudomonas aeruginosa** [Breakpoints (µg/mL): 4 (S), 8 (I), 16 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 16 | 15 | 93.75 | 6 | 5 | 83.33 | 15 | 93.75 | 8 | 7 | 1 | 0 | 0 | | Fresh | 13 | 13 | 100 | 11 | 11 | 100 | 13 | 100 | 0 | 13 | 0 | 0 | 0 | | Clinical Seeded | 14 | 14 | 100 | 14 | 14 | 100 | 14 | 100 | 0 | 14 | 0 | 0 | 0 | K223493 - Page 23 of 42 {23} | | Tot | No. EA | EA % | Eval EA Tot | No. Eval EA | Eval EA % | No. CA | CA % | No. R or NS | No. S | min | maj | vmj | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | Combined | 43 | 42 | 97.67 | 31 | 30 | 96.77 | 42 | 97.67 | 8 | 34 | 1 | 0 | 0 | | **Imipenem – *Acinetobacter baumannii* complex [Breakpoints (µg/mL): 2 (S), 4 (I), 8 (R)]** | | | | | | | | | | | | | | | Challenge Seeded | 10 | 10 | 100 | 0 | 0 | NA | 10 | 100 | 10 | 0 | 0 | 0 | 0 | | Fresh | 3 | 3 | 100 | 0 | 0 | NA | 3 | 100 | 3 | 0 | 0 | 0 | 0 | | Clinical Seeded | 26 | 25 | 96.15 | 2 | 1 | 50 | 26 | 100 | 13 | 13 | 0 | 0 | 0 | | Combined | 39 | 38 | 97.44 | 2 | 1 | 50 | 39 | 100 | 26 | 13 | 0 | 0 | 0 | | **Imipenem – Enterobacterales [Breakpoints (µg/mL): 1 (S), 2 (I), 4 (R)]** | | | | | | | | | | | | | | | Challenge Seeded | 57 | 54 | 94.74 | 6 | 3 | 50 | 55 | 96.49 | 12 | 43 | 2 | 0 | 0 | | Fresh | 96 | 93 | 96.88 | 4 | 1 | 25 | 94 | 97.92 | 0 | 96 | 1 | 1 | 0 | | Clinical Seeded | 60 | 58 | 96.67 | 4 | 2 | 50 | 60 | 100 | 8 | 52 | 0 | 0 | 0 | | Combined | 213 | 205 | 96.24 | 14 | 6 | 42.86 | 209 | 98.12 | 20 | 191 | 3 | 1 | 0 | | **Meropenem – *Acinetobacter baumannii* complex [Breakpoints (µg/mL): 2 (S), 4 (I), 8 (R)]** | | | | | | | | | | | | | | | Challenge Seeded | 10 | 10 | 100 | 1 | 1 | 100 | 10 | 100 | 10 | 0 | 0 | 0 | 0 | | Fresh | 3 | 3 | 100 | 0 | 0 | NA | 3 | 100 | 3 | 0 | 0 | 0 | 0 | | Clinical Seeded | 26 | 24 | 92.31 | 13 | 11 | 84.62 | 26 | 100 | 14 | 12 | 0 | 0 | 0 | | Combined | 39 | 37 | 94.87 | 14 | 12 | 85.71 | 39 | 100 | 27 | 12 | 0 | 0 | 0 | | **Meropenem – Enterobacterales [Breakpoints (µg/mL): 1 (S), 2 (I), 4 (R)]** | | | | | | | | | | | | | | | Challenge Seeded | 57 | 53 | 92.98 | 6 | 2 | 33.33 | 55 | 96.49 | 12 | 44 | 2 | 0 | 0 | | Fresh | 113 | 112 | 99.12 | 2 | 1 | 50 | 112 | 99.12 | 0 | 113 | 1 | 0 | 0 | | Clinical Seeded | 224 | 223 | 99.55 | 11 | 10 | 90.91 | 223 | 99.55 | 7 | 216 | 1 | 0 | 0 | | Combined | 394 | 388 | 98.48 | 19 | 13 | 68.42 | 390 | 98.98 | 19 | 373 | 4 | 0 | 0 | | **Meropenem – *Pseudomonas aeruginosa* [Breakpoints (µg/mL): 2 (S), 4 (I), 8 (R)]** | | | | | | | | | | | | | | | Challenge Seeded | 16 | 14 | 87.5 | 10 | 8 | 80 | 13 | 81.25 | 10 | 5 | 3 | 0 | 0 | | Fresh | 12 | 12 | 100 | 6 | 6 | 100 | 12 | 100 | 1 | 11 | 0 | 0 | 0 | | Clinical Seeded | 15 | 14 | 93.33 | 12 | 11 | 91.67 | 14 | 93.33 | 2 | 12 | 1 | 0 | 0 | | Combined | 43 | 40 | 93.02 | 28 | 25 | 89.29 | 39 | 90.7 | 13 | 28 | 4 | 0 | 0 | | **Minocycline – *Acinetobacter baumannii* complex [Breakpoints (µg/mL): 4 (S), 8 (I), 16 (R)]** | | | | | | | | | | | | | | | Challenge Seeded | 10 | 10 | 100 | 10 | 10 | 100 | 6 | 60 | 3 | 3 | 4 | 0 | 0 | | Fresh | 3 | 3 | 100 | 3 | 3 | 100 | 3 | 100 | 3 | 0 | 0 | 0 | 0 | | Clinical Seeded | 26 | 25 | 96.15 | 11 | 10 | 90.91 | 24 | 92.31 | 6 | 18 | 2 | 0 | 0 | | Combined | 39 | 38 | 97.44 | 24 | 23 | 95.83 | 33 | 84.62 | 12 | 21 | 6 | 0 | 0 | | **Minocycline – Enterobacterales [Breakpoints (µg/mL): 4 (S), 8 (I), 16 (R)]** | | | | | | | | | | | | | | | Challenge Seeded | 58 | 56 | 96.55 | 48 | 46 | 95.83 | 46 | 79.31 | 13 | 41 | 11 | 1 | 0 | | Fresh | 98 | 93 | 94.9 | 93 | 88 | 94.62 | 89 | 90.82 | 11 | 79 | 8 | 1 | 0 | | Clinical Seeded | 62 | 60 | 96.77 | 52 | 50 | 96.15 | 60 | 96.77 | 8 | 52 | 2 | 0 | 0 | | Combined | 218 | 209 | 95.87 | 193 | 184 | 95.34 | 195 | 89.45 | 32 | 172 | 21 | 2 | 0 | | **Piperacillin-Tazobactam – *Acinetobacter baumannii* complex [Breakpoints (µg/mL): 16 (S), 32-64 (I), 128 (R)]** | | | | | | | | | | | | | | | Challenge Seeded | 10 | 10 | 100 | 0 | 0 | NA | 10 | 100 | 10 | 0 | 0 | 0 | 0 | | Fresh | 3 | 3 | 100 | 0 | 0 | NA | 3 | 100 | 3 | 0 | 0 | 0 | 0 | K223493 - Page 24 of 42 {24} | | Tot | No. EA | EA % | Eval EA Tot | No. Eval EA | Eval EA % | No. CA | CA % | No. R or NS | No. S | min | maj | vmj | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | Clinical Seeded | 26 | 25 | 96.15 | 3 | 2 | 66.67 | 25 | 96.15 | 14 | 12 | 1 | 0 | 0 | | Combined | 39 | 38 | 97.44 | 3 | 2 | 66.67 | 38 | 97.44 | 27 | 12 | 1 | 0 | 0 | | Piperacillin-Tazobactam – Enterobacterales [Breakpoints (μg/mL): 8 (S), 16 (I), 32 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 55 | 54 | 98.18 | 14 | 13 | 92.86 | 53 | 96.36 | 21 | 32 | 2 | 0 | 0 | | Fresh | 104 | 101 | 97.12 | 15 | 12 | 80 | 100 | 96.15 | 1 | 96 | 4 | 0 | 0 | | Clinical Seeded | 161 | 158 | 98.14 | 14 | 11 | 78.57 | 159 | 98.76 | 15 | 145 | 1 | 1 | 0 | | Combined | 320 | 313 | 97.81 | 43 | 36 | 83.72 | 312 | 97.5 | 37 | 273 | 7 | 1 | 0 | | Piperacillin-Tazobactam – Pseudomonas aeruginosa [Breakpoints (μg/mL): 16 (S), 32-64 (I), 128 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 16 | 16 | 100 | 9 | 9 | 100 | 16 | 100 | 7 | 8 | 0 | 0 | 0 | | Fresh | 12 | 11 | 91.67 | 11 | 10 | 90.91 | 11 | 91.67 | 1 | 11 | 1 | 0 | 0 | | Clinical Seeded | 15 | 15 | 100 | 13 | 13 | 100 | 15 | 100 | 2 | 13 | 0 | 0 | 0 | | Combined | 43 | 42 | 97.67 | 33 | 32 | 96.97 | 42 | 97.67 | 10 | 32 | 1 | 0 | 0 | | Tobramycin – Enterobacterales [Breakpoints (μg/mL): 4 (S), 8 (I), 16 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 57 | 55 | 96.49 | 45 | 43 | 95.56 | 50 | 87.72 | 31 | 22 | 7 | 0 | 0 | | Fresh | 98 | 92 | 93.88 | 96 | 90 | 93.75 | 91 | 92.86 | 12 | 81 | 7 | 0 | 0 | | Clinical Seeded | 61 | 60 | 98.36 | 59 | 58 | 98.31 | 59 | 96.72 | 6 | 55 | 2 | 0 | 0 | | Combined | 216 | 207 | 95.83 | 200 | 191 | 95.5 | 200 | 92.59 | 49 | 158 | 16 | 0 | 0 | | Tobramycin – Pseudomonas aeruginosa [Breakpoints (μg/mL): 4 (S), 8 (I), 16 (R)] | | | | | | | | | | | | | | | Challenge Seeded | 16 | 16 | 100 | 10 | 10 | 100 | 15 | 93.75 | 8 | 8 | 1 | 0 | 0 | | Fresh | 12 | 11 | 91.67 | 12 | 11 | 91.67 | 12 | 100 | 1 | 11 | 0 | 0 | 0 | | Clinical Seeded | 15 | 14 | 93.33 | 15 | 14 | 93.33 | 14 | 93.33 | 1 | 14 | 1 | 0 | 0 | | Combined | 43 | 41 | 95.35 | 37 | 35 | 94.59 | 41 | 95.35 | 10 | 33 | 2 | 0 | 0 | ¹ Due to low CA (61.9%), K. oxytoca and M. morganii claims are not indicated for testing with the PBC Separator with Selux AST System for Ampicillin-Sulbactam. Perform an alternative method of testing prior to reporting results for the following antibiotic/organism combination: Ampicillin-Sulbactam: K. oxytoca, M. morganii ² Perform an alternative method of testing prior to reporting of results for the following antibiotic/organism combination: Cefazolin-E. coli when the Selux AST System MIC is 4 μg/mL due to the occurrence of minor errors, that were in essential agreement, resulting in a category agreement below 90%. EA – Essential Agreement CA – Category Agreement Eval – Evaluable isolates R – Resistant isolates NS – Non-susceptible isolates S – susceptible isolates min – minor errors maj – major errors vmj – very major errors Amikacin. A total of 38 A. baumannii isolates were evaluated with amikacin. The combined results from clinical and challenge isolate testing demonstrated and EA of 92.11% and CA of 94.74%. There were 2 minor, 0 major, and 0 very major errors. Overall, performance is acceptable. A total of 216 Enterobacterales isolates were evaluated with amikacin. The combined results from clinical and challenge isolate testing demonstrated and EA of 96.3% and CA of 98.61%. There were 3 minor, 0 major, and 0 very major errors. Overall, performance is acceptable. K223493 - Page 25 of 42 {25} A total of 44 P. aeruginosa isolates were evaluated with amikacin. The combined results from clinical and challenge isolate testing demonstrated and EA of 95.45% and CA of 90.91%. There were 4 minor, 0 major, and 0 very major errors. Overall, performance is acceptable. **Amoxicillin-Clavulanate.** A total of 330 Enterobacterales isolates were evaluated with amoxicillin-clavulanate. The combined results from clinical and challenge isolate testing demonstrated and EA of 99.39% and CA of 89.39% which was considered acceptable since all of the categorical errors were minor, and the EA of the evaluable results was good (>95%). When evaluating results by individual species, E. coli had CA <90% which was considered acceptable since all of the categorical errors were minor, and the EA of evaluable results was good (>95%). Overall, performance is acceptable. A limitation statement is included in the device labeling to address the lack of testing with resistant P. mirabilis and P. vulgaris isolates. **Ampicillin.** A tot…
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