(82 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, including Streptococcus pneumoniae. After inoculation, panels are incubated for 20 - 24 hours at 35°C +/- 1°C in a non-CO2 incubator, and read visually. Alternatively, the panels can be incubated in and read by the MicroScan® WalkAway System, according to the Package Insert.
This particular submission is for the addition of the antimicrobial Moxifloxacin at concentrations of 0.03 to 8 ug/ml to the test panel.
The organisms which may be used for Moxifloxacin susceptibility testing in this panel are:
Streptococcus pneumoniae (including penicillin resistant strains) Streptococcus pyogenes Streptoccocus agalactiae Streptococcus constellatus Streptococcus anginosus Viridans group streptococci
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, including Streptococcus pneumoniae.
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® WalkAway System.
Here's a breakdown of the acceptance criteria and study information for the MicroScan® MICroSTREP plus® Panels with Moxifloxacin, based on the provided 510(k) summary:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (from FDA Guidance Document: "Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA") | Reported Device Performance (Moxifloxacin) |
|---|---|
| Substantial Equivalent Performance (compared to a CLSI frozen Reference Panel) | Overall Essential Agreement of 97.3% |
| Acceptable Reproducibility and Precision | Demonstrated acceptable reproducibility and precision with Moxifloxacin |
| Acceptable Quality Control Testing | Demonstrated acceptable results for Moxifloxacin |
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Sample Size: Not explicitly stated as a single number of isolates. However, the study mentions:
- "fresh and stock Efficacy isolates"
- "stock Challenge strains"
- The overall Essential Agreement of 97.3% for Moxifloxacin suggests a substantial number of isolates were tested to achieve this agreement rate across different concentrations.
- Data Provenance: Not explicitly stated (e.g., country of origin). The data is retrospective, as it compares the performance of the device to an established CLSI frozen Reference Panel.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
- The ground truth for the test set was not established by individual experts in this context. Instead, it was established by a CLSI frozen Reference Panel. This panel itself represents a consensus standard for antimicrobial susceptibility testing, implying that its development and validation involved a panel of experts in microbiology and antimicrobial susceptibility. No specific number or qualifications of experts are given for the initial establishment of the CLSI reference method.
4. Adjudication Method for the Test Set
- No explicit adjudication method (like 2+1 or 3+1) is described. The comparison was directly between the MicroScan MICroSTREP plus Panel and the CLSI frozen Reference Panel. For challenge strains, the method was comparison to "Expected Results determined prior to the evaluation," which implies pre-defined reference values.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was Done
- No, a Multi Reader Multi Case (MRMC) comparative effectiveness study was not done. This study focuses on the agreement between the device and a reference method, not on human reader performance with or without AI assistance. While the panel can be read manually or by the MicroScan® WalkAway System, the study primarily evaluates the device's accuracy against the CLSI reference.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
- Yes, a standalone study was done. The "MicroScan® MICroSTREP plus® Panel" itself is the "algorithm/device" being tested. Its performance (Essential Agreement) was compared directly to the CLSI frozen Reference Panel, representing its standalone accuracy. While it can be read manually, the core evaluation confirms the performance of the panel itself.
7. The Type of Ground Truth Used
- The primary ground truth used was a CLSI frozen Reference Panel. For "Challenge strains," the ground truth was "Expected Results determined prior to the evaluation," which would have been established using a recognized reference method, likely aligned with CLSI standards. This is a form of expert consensus standard in microbiology.
8. The Sample Size for the Training Set
- The document does not provide information on a "training set" in the context of machine learning or AI development. This device is an antimicrobial susceptibility test panel, which operates based on biochemical reactions and defined dilutions, not a machine learning algorithm that requires a separate training set. Its "development" would involve optimizing dilutions and components to match reference methods.
9. How the Ground Truth for the Training Set Was Established
- As there is no explicit "training set" described for a machine learning model, this question is not applicable to the information provided. The "ground truth" for the device's development would be established through established microbiological reference methods (like CLSI standards), but this is not a separate training set as understood in AI/ML contexts.
§ 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).