(56 days)
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 cocci. 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 addition of the antimicrobial Daptomycin at concentrations of 0.03 to 16 mcg/ml to the test panel.
The gram-positive organisms which may be used for Daptomycin susceptibility testing in this panel are:
Enterococcus faecalis (vancomycin-susceptible and resistant strains)
Enterococcus faecium (including vancomycin-resistant strains)
Staphylococcus aureus (including methicillin-resistant strains)
Staphylococcus epidermidis (including methicillin-resistant strains)
Staphylococus haemolyticus
Streptococcus agalactiae
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 cocci.
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 summary of the acceptance criteria and study details for the MicroScan® Dried Gram-Positive MIC/Combo Panels with Daptomycin, based on the provided text:
Acceptance Criteria and Device Performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Overall Essential Agreement with NCCLS frozen Reference Panel | >97% for Daptomycin |
| Reproducibility for Daptomycin (all inoculum methods and instruments) | Acceptable |
| Quality Control testing for Daptomycin | Acceptable |
Study Details
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Sample Sizes and Data Provenance:
- Test Set:
- Clinical Isolates: "fresh and stock Efficacy isolates"
- Challenge Strains: "stock Challenge strains"
- The specific number of isolates/strains is not provided, only the categories.
- Data Provenance: Not explicitly stated, but clinical isolates often come from various clinical sites (implicitly retrospective as 'stock' or 'fresh' isolates) for such studies. Challenge strains are typically laboratory-derived.
- Test Set:
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Number of Experts and Qualifications for Ground Truth (Test Set):
- External Evaluation: The study was an "external evaluation," implying independent assessment.
- Ground Truth Determination: Comparison was made against an "NCCLS frozen Reference panel" and "Expected Results determined prior to the evaluation" for challenge strains. No specific number or qualifications of experts involved in establishing the NCCLS reference or "expected results" are detailed in this summary, but these are standard reference methods in microbiology.
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Adjudication Method (Test Set):
- Not explicitly stated. The comparison was primarily against a reference panel and predetermined expected results.
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Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
- No MRMC comparative effectiveness study involving human readers and AI assistance was mentioned. This device is an automated antimicrobial susceptibility testing system, not an image-based diagnostic intended for human interpretation with or without AI augmentation.
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Standalone Performance (Algorithm Only):
- Yes, this was a standalone performance study. The "MicroScan® Dried Gram-Positive MIC/Combo Panel" itself is the device being evaluated for its ability to determine MICs compared to a reference standard. The results are read either "visually or with MicroScan instrumentation." The reported performance of ">97% essential agreement" refers to the device's accuracy in producing results.
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Type of Ground Truth Used:
- Reference Standard: NCCLS frozen Reference Panel. NCCLS (now CLSI) reference panels are accepted gold standards for antimicrobial susceptibility testing, representing expert consensus on methodology and expected results for known strains.
- Predetermined Expected Results: For Challenge strains, results were compared to "Expected Results determined prior to the evaluation," which would have been established using a defined reference method.
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Sample Size for Training Set:
- Not applicable as this is not a machine learning model requiring a training set in the typical sense. The device's performance is based on its inherent biochemical and mechanical design, not on a learned algorithm from a dataset in the way AI/ML products are.
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How Ground Truth for Training Set was Established:
- Not applicable for the reason stated above. The system's "training" would be its initial chemical and biological design and manufacturing processes, validated through studies like this.
§ 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).