(35 days)
The MicroScan® MICroSTREP plus® Panel is used to determine quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of aerobic streptococci. After inoculation, panels are incubated for 20 - 24 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 addition of the antimicrobial Daptomycin at concentrations of 0.25 to 8 µg/ml to the test panel.
The organisms which may be used for Daptomycin susceptibility testing in this panel are:
Streptococcus pyogenes Streptoccocus agalactiae Streptococcus dysglactiae subsp.equisimilis
MicroScan MICroSTREP plus panels are designed for use in determining quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of aerobic streptococci.
The antimicrobial susceptibility tests are miniaturizations of the broth dilution susceptibility test that have been diluted in water and dehydrated. Various antimicrobial agents are diluted in water, buffer or minute concentrations of broth to concentrations bridging the range of clinical interest. Panels are rehydrated with 115 µl Mueller-Hinton broth supplemented with 2-5% lysed horse blood (LHB), after inoculation of the broth with a standardized suspension of the organism. After incubation in a non-CO2 incubator for 20-24 hours, the minimum inhibitory concentration (MIC) for the test organism is manually read by observing the lowest antimicrobial concentration showing inhibition of growth. Alternatively, the panel can be incubated in and read by the MicroScan® WalkAwav System.
Here's a breakdown of the acceptance criteria and the study details for the MicroScan® MICroSTREP plus® Panels with Daptomycin, based on the provided text:
Acceptance Criteria and Device Performance
| Acceptance Criteria Category | Specific Criteria | Reported Device Performance |
|---|---|---|
| Overall Performance | Acceptable performance when compared with a CLSI frozen Reference Panel, as defined in the FDA document "Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA", dated August 28, 2009. | Overall Essential Agreement of 97% for Daptomycin when compared with the frozen Reference panel. |
| Reproducibility | Acceptable reproducibility and precision | Demonstrated acceptable reproducibility and precision with Daptomycin. |
| Quality Control | Acceptable results | Demonstrated acceptable results for Daptomycin. |
Study Details
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Sample Size used for the test set and the data provenance:
- Sample Size: Not explicitly stated as a number. The text mentions "fresh and stock Efficacy isolates and stock Challenge strains."
- Data Provenance: Not explicitly stated (e.g., country of origin). It was an "external evaluation." The study appears to be retrospective, using "stock" isolates and challenge strains.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- This information is not provided in the given text.
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Adjudication method (e.g., 2+1, 3+1, none) for the test set:
- This information is not provided in the given text. The comparison was made against "Expected Results determined prior to the evaluation" for challenge strains, and a "CLSI frozen Reference panel" for general performance. This implies a predefined ground truth rather than a live adjudication process.
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If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:
- No. This was not an MRMC comparative effectiveness study involving human readers and AI assistance. This device is an Antimicrobial Susceptibility Test (AST) system, not an AI-powered diagnostic tool. The "read methods" mentioned are manual visual reading or the MicroScan® WalkAway System, which is an automated instrument, not an AI system in the modern sense of medical imaging or diagnostic AI.
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If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- The device itself (MicroScan® MICroSTREP plus® Panel) determines the MIC. The performance comparison was done against a CLSI reference panel. While there's an option for the MicroScan® WalkAway System to read the panels, the core evaluation is on the panel's ability to accurately reflect MIC, which can be interpreted manually or by the instrument. Thus, the performance of the "panel" itself (the algorithm being the chemical reactions resulting in MIC) was assessed in a standalone manner against the reference.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- For general performance, the ground truth was a CLSI frozen Reference Panel.
- For challenge strains, the ground truth was "Expected Results determined prior to the evaluation." This likely refers to results from established reference methods or known MICs for those specific strains.
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The sample size for the training set:
- This information is not provided in the given text, as this is not a machine learning or AI-based device that typically has a "training set." The development of such a test involves chemical and biological optimization rather than data-driven machine learning training.
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How the ground truth for the training set was established:
- Not applicable, as there is no "training set" in the context of this device's development.
§ 866.1640 Antimicrobial susceptibility test powder.
(a)
Identification. An antimicrobial susceptibility test powder is a device that consists of an antimicrobial drug powder packaged in vials in specified amounts and intended for use in clinical laboratories for determining in vitro susceptibility of bacterial pathogens to these therapeutic agents. Test results are used to determine the antimicrobial agent of choice in the treatment of bacterial diseases.(b)
Classification. Class II (performance standards).