(43 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 - 24 hours at 35℃ +/- 1℃ in a non-CO2 incubator. Results are read either visually or with MicroScan instrumentation, according to the Package Insert.
This particular submission is for the addition of the antimicrobial vancomycin at concentrations of 0.25 to 128 mcg/ml to the test panel.
The gram-positive organisms which may be used for vancomycin susceptibility testing in this panel are:
Enterococcus spp. (e.g., Enterococcus faecalis)
Staphylococcus spp. (including Staphylococcus aureus)
Staphylococcus epidermidis (including methicillin-resistant strains)
Streptococcus agalactiae
Streptococcus bovis
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 16-24 hours, the minimum inhibitory concentration (MIC) for the test organism is read by determining the lowest antimicrobial concentration showing inhibition of growth.
This solicitation is for the addition of the antimicrobial vancomycin at concentrations of 0.25 to 128 mcg/ml to MicroScan® Dried Gram-Positive MIC/Combo Panels.
1. Table of Acceptance Criteria & Reported Device Performance:
| Performance Metric | Acceptance Criteria (from FDA's "Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems") | Reported Device Performance (Vancomycin) |
|---|---|---|
| Overall Essential Agreement | >90% for vancomycin | >99% |
| Inoculum Reproducibility | Acceptable reproducibility | Acceptable |
| Instrument Reproducibility | Acceptable reproducibility | Acceptable |
| Quality Control | Acceptable results | Acceptable |
2. Sample Size & Data Provenance:
- Test Set Sample Size: The document does not specify the exact number of isolates used for the external evaluation. It mentions "fresh and stock Efficacy isolates and stock Challenge strains."
- Data Provenance: Not explicitly stated, but "external evaluation" suggests different sites. The document implies a multicenter evaluation, as it refers to "external evaluation" in plural sense, and thus suggests multicenter data.
- Retrospective/Prospective: Not explicitly stated. The use of "fresh and stock Efficacy isolates" suggests a mix, where "fresh" could imply prospective collection for the study, while "stock" would be retrospective.
3. Number of Experts & Qualifications for Ground Truth (Test Set):
- The document does not specify the number or qualifications of experts used to establish the ground truth for the test set. Instead, it refers to a "CLSI (formerly NCCLS) frozen Reference Panel" as the gold standard.
4. Adjudication Method for the Test Set:
- Not applicable as the ground truth was established by comparison to a reference standard (CLSI frozen Reference Panel), not through expert adjudication of images/data from the device. "Challenge strains were compared to Expected Results determined prior to the evaluation".
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
- No, an MRMC comparative effectiveness study was not done. The study focuses on the standalone performance of the device against a reference method.
6. Standalone Performance Study:
- Yes, a standalone (algorithm only) performance study was conducted. The MicroScan® Dried Gram-Positive MIC/Combo Panel's performance was compared directly to a CLSI frozen Reference Panel.
7. Type of Ground Truth Used:
- Reference Standard: CLSI (Clinical and Laboratory Standards Institute, formerly NCCLS) frozen Reference Panel. This is considered a gold standard for antimicrobial susceptibility testing. For challenge strains, "Expected Results" determined prior to the evaluation were used.
8. Sample Size for the Training Set:
- Not applicable for this type of device and study. Antimicrobial susceptibility test (AST) systems are typically validated against established reference methods (like CLSI) rather than being "trained" in the machine learning sense. The device's underlying principles are based on broth dilution, not a trainable algorithm.
9. How Ground Truth for the Training Set was Established:
- Not applicable (see point 8). The "ground truth" for the development of the AST system itself would be the established scientific principles of antimicrobial activity and bacterial growth inhibition, as defined and standardized by organizations like CLSI.
§ 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).