Search Results

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

Indications for Use:
The Selux Gram-Positive Panel is intended for use with the Selux AST System as an in vitro test to determine the susceptibility of isolated colonies of specific Staphylococcus species to species to specific antimicrobial agents when used as instructed.

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

• Ampicillin: Enterococcus faecium, Enterococcus faecalis
• Clindamycin: Staphylococcus aureus, Staphylococcus epidermidis
• Ceftaroline: Staphylococcus aureus
• Daptomycin: Staphylococcus aureus, Enterococcus faecalis
• Delafloxacin: Staphylococcus aureus, Staphylococcus haemolyticus, Enterococcus faecalis
• Eravacycline: Staphylococcus aureus, Enterococcus faecalis
• Erythromycin: Staphylococcus aureus
• Linezolid: Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Enterococcus faecium, Enterococcus faecalis
• Levofloxacin: Enterococcus faccium, Enterococcus faecalis, methicillin-susceptible Staphylococcus aureus
• Minocycline: Staphylococcus aureus
• Oxacillin: Staphylococcus aureus, Staphylococcus lugdunensis
• Penicillin: Enterococcus faecium, Enterococcus faecalis, Staphylococcus aureus
• Trimethoprim: Staphylococcus aureus, Coagulase-Negative Staphylococci (including S. capitus, S. haemolyticus, S. saprophyticus, S. simulans)
• Vancomycin: Staphylococcus aureus, Coagulase-Negative Staphylococci (CoNS) (including S. capitus, S. cohnii, S. epidermidis, S. haemolyticus, S. internedius group, S. lugdunensis, S. saprophyticus, S. schleiferi, S. simulans) Enterococcus faecium, Enterococcus faecalis

The Selux 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, Staphylococcus lugdunensis

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

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

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

Here's a breakdown of the acceptance criteria and study information for the Selux AST System, based on the provided FDA 510(k) summary:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria for each antimicrobial-organism combination are not explicitly stated as numerical targets (e.g., "EA must be >90%"). Instead, the document presents the observed performance and notes where EA (Essential Agreement) falls below 90%, implying that 90% is a general benchmark for acceptable performance, with specific justifications or labeling changes for values below this. The table below summarizes the reported performance.

¹ EA performance (<90%) is addressed in limitation statements in the device labeling.

2. Sample Size Used for the Test Set and Data Provenance

• Test Set Sample Size:
  • Clinical Isolates: 706 (193 contemporary and 513 stock/frozen)
  • Challenge Isolates: 159
  • Total Samples Tested: 865
  • The number of data points for various antimicrobial-organism combinations ranged from 39 to 311.
• Data Provenance: The document states "Contemporary and frozen clinical isolates from diverse geographic locations across the US were evaluated for performance as well as stock (frozen/banked) challenge isolates." This indicates a mix of retrospective (stock/frozen) and potentially prospective (contemporary) data collected from multiple sites across the US.

3. Number of Experts Used to Establish Ground Truth for the Test Set and Their Qualifications

The document does not explicitly state the number of experts or their specific qualifications for establishing the ground truth. It mentions that the Selux AST System results were compared with "triplicate broth microdilution results performed at an independent reference laboratory."

4. Adjudication Method for the Test Set

The ground truth was established by "triplicate broth microdilution results performed at an independent reference laboratory." This implies that the accepted standard for antimicrobial susceptibility testing (broth microdilution) was performed independently, and the "triplicate" nature suggests internal verification or averaging, rather than a formal adjudication process involving multiple human readers for discrepancies.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size

No, an MRMC comparative effectiveness study involving human readers with and without AI assistance was not conducted. The study evaluated the standalone performance of the Selux AST System against a reference method (broth microdilution), which is a device-to-device comparison, not a human reader study.

6. If a Standalone Study Was Done

Yes, a standalone study was done. The entire "Clinical Studies" section describes the performance of the Selux AST System (the algorithm/device only) in determining antimicrobial susceptibility, comparing its results directly to a reference method (broth microdilution). Human involvement was in operating the system and performing the reference method, not in interpreting the results from the Selux system.

7. The Type of Ground Truth Used

The ground truth used was reference standard testing, specifically triplicate broth microdilution results performed at an independent reference laboratory.

8. The Sample Size for the Training Set

The document does not explicitly state the sample size for the training set. The "Clinical Studies" section describes the test set used for performance evaluation.

9. How the Ground Truth for the Training Set Was Established

Since the training set size and details are not provided, information on how its ground truth was established is also not available in the document.

Ask a specific question about this device