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VITEK® 2 AST Streptococcus Vancomycin is designed for antimicrobial susceptibility testing of Streptococcus species. VITEK® 2 AST Streptococcus Vancomycin is a quantitative test intended for use with the VITEK® 2 and ViTEK® 2 Compact Systems as a laboratory aid in th determination of in vitro susceptibility to antimicrobial agents. Vancomycin has been shown to be active against most strains of the microorganisms listed below, according to the FDA label for this antimicrobial.

Active in vitro and in clinical infections Viridans group streptococci

In vitro data are available, but their clinical significance is unknown Streptococcus agalactiae Streptococcus pyogenes

The VITEK® 2 Antimicrobial Susceptibility Test (AST) is intended to be used with the VITEK® 2 System as an automated method for quantitative or qualitative susceptibility testing of isolated colonies for the most clinically significant aerobic gram-negative bacilli, Staphylococcus spp., Enterococcus spp., Streptococcus spp. and clinically significant yeast.

The antimicrobial presented in VITEK 2 AST Cards is in concentrations equivalent by efficacy to standard method concentrations in mcg/m). 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 - 0 .50% saline before being used to rehydrate the antimicrobial medium within the card. The VITEK 2 System automatically fills, seals and places the card into the incubator/reader. The VITEK 2 Compact has a manual filling and sealing operation. 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 summary of the acceptance criteria and study details for the VITEK® 2 AST Streptococcus Vancomycin, based on the provided text:

Acceptance Criteria and Device Performance

Study Details

1. Sample Size Used for the Test Set and Data Provenance:

   • Test Set Sample Size: Not explicitly stated, but the study involved "fresh clinical isolates and stock challenge strains."
   • Data Provenance: Not explicitly stated, but the study was an "external evaluation," suggesting data collected outside of bioMérieux's direct control, likely from various clinical settings. No country of origin is specified, but the submission is to the US FDA. The isolates included "fresh clinical isolates," indicating a prospective element, and "stock challenge strains," which could be considered retrospective or pre-existing.

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

   • This information is not provided in the document. The ground truth was established by a reference method.

3. Adjudication Method for the Test Set:

   • None mentioned. The comparison was directly against the CLSI broth microdilution reference method.

4. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:

   • No MRMC comparative effectiveness study was mentioned. The study focused on the performance of the automated system against a reference method, not on human reader improvement with or without AI assistance.

5. Standalone Performance (Algorithm Only, No Human-in-the-Loop):

   • Yes, a standalone performance evaluation was conducted. The VITEK® 2 AST Streptococcus Vancomycin system, which is a "fully automated short-term incubation cycle antimicrobial susceptibility device," was compared directly to the CLSI broth microdilution reference method. This evaluates the algorithm's (and instrument's) performance without human interpretation as part of the core measurement.

6. Type of Ground Truth Used:

   • Reference Method: The ground truth was established using the CLSI broth microdilution reference method, which is a widely accepted laboratory standard for determining antimicrobial susceptibility.

7. Sample Size for the Training Set:

   • This information is not provided in the document. The document describes the validation study (test set), but not the training of the underlying algorithms, which is typical for 510(k) summaries where the focus is on performance validation.

8. How the Ground Truth for the Training Set Was Established:

   • This information is not provided in the document, as the training set details are not discussed.

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