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The VITEK® Gram Negative Gatifloxacin is designed for antimicrobial susceptibility testing of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Acinetobacter lwoffii, Citrobacter koseri, Citrobacter freundii, Enterobacter aerogenes, Enterobacter cloacae, Klebsiella oxytoca, Morganella morganii and Proteus vulgaris. It is intended for use with the VITEK® System as a laboratory aid in the determination of in vitro susceptibility to antimicrobial agents.

The VITEK GNS 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 automatically fills, seals and places the card into the incubator/reader. The VITEK monitors the growth of each well in the card over a defined period of time (up to 15 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 the study that demonstrates the VITEK® Gram Negative Gatifloxacin device meets those criteria, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

Important Note: The document implies the acceptance criteria through its comparison to the "NCCLS reference agar dilution method" and references the "Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA, February 5, 2003." While specific numerical thresholds for "acceptable" reproducibility and quality control are not explicitly stated, the FDA's acceptance of the 97.9% Essential Agreement implies this met their requirements.

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

• Sample Size for Test Set: The document mentions an "external evaluation... with fresh and stock clinical isolates and stock challenge strains." It does not provide a specific number for the sample size (i.e., the number of isolates or tests performed).
• Data Provenance: The data provenance is not explicitly stated in terms of country of origin. The study was an "external evaluation." It utilized both "fresh and stock clinical isolates" (implying retrospective clinical data or recently collected clinical data) and "stock challenge strains" (implying laboratory-controlled prospective data).

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

This information is not provided in the document. The ground truth was established by the "NCCLS reference agar dilution method," which is a laboratory standard rather than expert consensus on individual cases.

4. Adjudication Method for the Test Set

This information is not applicable as the ground truth was established by a laboratory reference method (NCCLS agar dilution), not by human expert interpretation requiring adjudication.

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

No, a multi-reader multi-case comparative effectiveness study was not done. This device is an automated antimicrobial susceptibility testing system, and the study compares its performance against a reference laboratory method, not against human readers.

6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done

Yes, a standalone study was performed. The VITEK® system is a "Fully Automated Short-Term Incubation Cycle Antimicrobial Susceptibility Device." The study compared the VITEK® Gram Negative Gatifloxacin's performance directly against the NCCLS reference agar dilution method. The description of the VITEK® operation ("automatically fills, seals and places the card into the incubator/reader. The VITEK monitors the growth... a report is generated") indicates it operates without human intervention in the interpretive phase.

7. The Type of Ground Truth Used

The ground truth used was the NCCLS reference agar dilution method. This is a laboratory-based, established standard methodology for determining minimum inhibitory concentrations (MICs) of antimicrobials.

8. The Sample Size for the Training Set

The document does not provide information regarding a "training set" or its sample size. The VITEK® system is presented as a device that performs a test, rather than an algorithm that learns from a training set in the typical machine learning sense. The development of the VITEK® system itself would have involved extensive R&D and calibration, but the specific term "training set" for this submission is not used.

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

As no training set is explicitly mentioned in the context of this 510(k) submission, the method for establishing its ground truth is not provided.

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