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The MicroScan® Dried Gram-Positive MIC/Combo Panel is used to determine quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of rapidly growing aerobic and facultative anaerobic gram-positive bacteria. After inoculation, panels are incubated for 16 - 20 hours at 35°C +/- 1°C in a non-CO2 incubator, and read either visually or with MicroScan instrumentation, according to the Package Insert.

This particular submission is for the reformulated antimicrobial Vancomycin at concentrations of 0.25 to 64 ug/ml to the test panel.

The gram-positive organisms which may be used for Vancomycin susceptibility testing in this panel are:

Enterococci (e.g., Enterococcus faecalis)

Staphylococci, including Staphylococcus aureus and Staphylococcus epidermidis (including heterogeneous methicillinresistant strains)

MicroScan Dried Gram-Positive MIC/Combo Panels are designed for use in determining quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of rapidly growing aerobic and facultative anaerobic gram-positive bacteria.

The antimicrobial susceptibility tests are miniaturizations of the broth dilution susceptibility test that have been diluted in broth and dehydrated. Various antimicrobial agents are diluted in broth to concentrations bridging the range of clinical interest. Panels are rehydrated with water after inoculation with a standardized suspension of the organism. After incubation in a non-CO2 incubator for 16-20 hours, the minimum inhibitory concentration (MIC) for the test organism is read by determining the lowest antimicrobial concentration showing inhibition of growth.

Here's a breakdown of the acceptance criteria and study details based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

2. Sample Size and Data Provenance

• Test Set Sample Size:
  • The document mentions "fresh and stock Efficacy isolates and stock Challenge strains" and "Reproducibility isolates." Specific numerical sample sizes for each of these categories are not provided.
  • The Essential Agreement figures are reported for Enterococcus spp. but the total number of isolates tested to achieve these percentages is not given.
• Data Provenance: The text does not specify the country of origin of the data. The study involved a reevaluation of clinical evaluation data. It is a retrospective analysis of existing data combined with new testing for reproducibility and quality control.

3. Number of Experts and Qualifications

• Number of Experts: Not specified.
• Qualifications of Experts: Not specified. The document refers to "CLSI frozen Reference Panel" as a comparator, implying that the ground truth was established using standard clinical laboratory methods, likely by trained microbiologists, but explicit details are missing.

4. Adjudication Method

• Adjudication Method: Not specified. The comparison is made against a "CLSI frozen Reference Panel," which acts as the reference standard. There is no mention of multiple experts independently reading and then adjudicating discrepancies.

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

• MRMC Study Done: No, an MRMC comparative effectiveness study was not done. This device is an automated antimicrobial susceptibility test (AST) system, not a diagnostic imaging device that typically involves human readers. The comparison is between the device's performance and a reference standard.
• Effect Size of Human Readers Improvement: Not applicable, as this was not an MRMC study.

6. Standalone Performance (Algorithm Only)

• Standalone Performance: Yes, the study evaluates the standalone performance of the MicroScan Dried Gram-Positive MIC/Combo Panel. It compares the panel's results (read either visually or with MicroScan instrumentation) against a CLSI frozen Reference Panel. The "MicroScan instrumentation" represents the automated component of the device's performance.

7. Type of Ground Truth Used

• Type of Ground Truth: The ground truth was established by a CLSI frozen Reference Panel. This is a recognized reference method for antimicrobial susceptibility testing, providing a reliable standard against which the device's performance can be measured.

8. Sample Size for the Training Set

• Training Set Sample Size: The document does not explicitly mention a "training set" or its size. The study described is a validation study comparing the modified panel's performance against a reference standard. If machine learning or AI was used in the panel's development, information about its training set would typically be separate from this validation study. However, the core technology described (microdilution MIC panels) is a biochemical testing method, not typically an AI/machine learning application requiring an explicit "training set" in the sense of AI models.

9. How Ground Truth for Training Set Was Established

• Ground Truth for Training Set: Not applicable/not provided. As noted above, the document doesn't detail a separate training set for an AI/machine learning model. For traditional AST panels like this, the "ground truth" for developing and calibrating the panel's concentrations and reading parameters would have been established through extensive microbiological research and correlation with clinical outcomes, usually against reference methods like broth microdilution, which is foundational to CLSI standards.

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