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VITEK® 2 Gram Positive Quinupristin is designed for antimicrobial susceptibility testing of Enterococcus faecium (vancomycin-resistant), Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus agalactiae. It is intended for use with the VITEK® 2 System as a laboratory aid in the determination of in vitro susceptibility to antimicrobial agents.

The VITEK 2 AST Cards are essentially miniaturized versions of the doubling dilution technique for determining the minimum inhibitory concentration (MIC) my microdilution methodology. The bacterial isolate to be tested is diluted to a standardized concentration in 0.45% saline before being used to rehydrate the antimicrobial medium within the card. The VITEK 2 automatically fills, seals and places the card into the incubator/reader. The VITEK 2 monitors the growth of each well in the card over a defined period of time (up to 18 hours). At the completion of the incubation cycle, a report is generated that contains the MIC value along with the interpretive category result for each antibiotic contained on the card.

Here's a breakdown of the acceptance criteria and study details for the VITEK® 2 Gram Positive Quinupristin/dalfopristin device, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

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

• Sample Size for Test Set: Not explicitly stated as a numerical value for the total number of isolates. The document mentions an "external evaluation was conducted with fresh and stock clinical isolates and stock challenge strains." This implies a varied collection but no specific count.
• Data Provenance: The external evaluation suggests that the clinical isolates were likely from a real-world setting, potentially encompassing multiple locations given the term "external evaluation." However, the exact country of origin or whether it was retrospective or prospective is not specified. "Fresh clinical isolates" imply prospective collection, while "stock clinical isolates" could be either.

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

This information is not provided in the document. The ground truth method (NCCLS microbroth dilution reference method) is stated, but not the process of establishing that ground truth or the involvement of human experts for this step.

4. Adjudication Method for the Test Set

This information is not provided in the document.

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

No, a MRMC comparative effectiveness study was not done. The study focused on the VITEK 2 device's performance against a reference method (NCCLS microbroth dilution) in a standalone manner, not comparing human readers with and without AI assistance.

6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) Was Done

Yes, a standalone study was done. The entire evaluation described is of the VITEK® 2 system's performance (an automated device/algorithm) in determining antimicrobial susceptibility. The "Essential Agreement" and comparison to a reference method are metrics of the standalone device's accuracy.

7. The Type of Ground Truth Used

The ground truth used was the NCCLS microbroth dilution reference method. This is considered a gold standard laboratory method for determining minimum inhibitory concentrations (MICs) of antimicrobials.

8. The Sample Size for the Training Set

The document does not mention a training set or any details related to machine learning model development. This device appears to be an automated instrument based on established principles of microbiology (microdilution methodology) rather than a machine learning algorithm that requires a separate training phase.

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

As there is no mention of a training set, this information is not applicable.

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