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The VITEK® 2 Antimicrobial Susceptibility Test (AST) is intended to be used with the VITEK® 2 System for the automated quantitative or qualitative susceptibility testing of isolated colonies for most clinically significant aerobic gram-negative bacilli, Staphylococcus spp., Enterococcus spp., Streptococcus agalactiae, and S. pneumoniae. The VITEK® 2 ESBL Test is a confirmatory test used to detect the presence of extended-spectrum beta-lactamases (ESBLs) in Escherichia coli, Klebsiella pneumoniae, and K. oxytoca. 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 ESBL Test is a confirmatory test for the presence of extended-spectrum beta-lactamases (ESBLs) in Escherichia coli, Klebsiella pneumoniae, and K. oxytoca. 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 antimicrobials presented in VITEK 2 ESBL Test are in concentrations equivalent by efficacy to standard method concentrations in ug/ml. The VITEK 2 AST Cards are essentially miniaturized versions of the doubling dilution technique for determining the minimum inhibitory concentration (MIC) 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 VITEK 2 ESBL Test result.

The VITEK® 2 ESBL Test is a confirmatory test for the presence of extended-spectrum beta-lactamases (ESBLs) in Escherichia coli, Klebsiella pneumoniae, and K. oxytoca.

Here's a breakdown of the acceptance criteria and study information:

1. Table of Acceptance Criteria and Reported Device Performance

The provided document mentions an overall "Category Agreement" as the key performance metric. It doesn't explicitly state a pre-defined acceptance criterion as a numerical threshold, but implies that 97.7% was acceptable.

2. Sample Size and Data Provenance

The document states:

• Sample Size (Test Set): Not explicitly stated with a specific number. It mentions tests for "fresh and stock clinical isolates and stock challenge strains."
• Data Provenance: Not explicitly stated (e.g., country of origin). The testing included "clinical isolates" and "stock challenge strains," suggesting a mix of real-world and controlled laboratory samples. The study involved "external evaluations," but the location of these evaluations is not specified.
• Retrospective/Prospective: Not explicitly stated. The phrase "fresh and stock clinical isolates" could suggest both retrospective (stock) and potentially prospective (fresh) collection, but it's not clear.

3. Number of Experts and Qualifications for Ground Truth

• Number of Experts: Not mentioned.
• Qualifications of Experts: Not mentioned.

4. Adjudication Method

• Adjudication Method: Not mentioned. The ground truth was established by the "NCCLS ESBL Disk Diffusion Confirmatory Test method," which is a laboratory reference method, implying a standard protocol rather than human expert adjudication in the traditional sense.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

• MRMC Study: No, this does not appear to be an MRMC comparative effectiveness study. The device is an automated in vitro diagnostic test, not an imaging interpretation or similar task where human readers would typically be involved in varying assistance levels. The comparison is between the automated system and a laboratory reference method.

6. Standalone Performance Study

• Standalone Performance: Yes, the study describes the standalone performance of the VITEK® 2 ESBL Test. It compares the automated system's results directly against the NCCLS ESBL Disk Diffusion Confirmatory Test method without human intervention in the interpretation process. The 97.7% overall Category Agreement represents this standalone performance.

7. Type of Ground Truth

• Type of Ground Truth: The ground truth was established using a laboratory reference method: the "NCCLS ESBL Disk Diffusion Confirmatory Test method." This is a standardized conventional microbiology technique.

8. Sample Size for Training Set

• Sample Size (Training Set): Not mentioned. The document describes the "VITEK 2 ESBL Test" and its performance, but does not provide details on the development or training of the VITEK 2 system's algorithms. It's possible that the "training" refers to internal validation during the device development that is not explicitly detailed in this summary, or that the system operates based on established thresholds rather than a machine learning model requiring a distinct training set.

9. How Ground Truth for Training Set Was Established

• How Ground Truth Was Established (Training Set): Not mentioned. As above, details regarding any training or developmental data for the VITEK® 2 system are not provided in this 510(k) summary.

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