(31 days)
The MicroScan® Synergies plus™ 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 enterococci and staphylococci. After inoculation, panels are incubated for 4.5 -- 18 hours at 35℃ +/- 1℃, in a WalkAway® SI, or equivalent, and read by the MicroScan® Instrumentation. Additionally, the panels may be incubated in a non-CO2 incubator and the Antimicrobial Susceptibility Testing (AST) portions can be read visually, according to the Package Insert.
This particular submission is for the addition of the antimicrobial Synercid, at concentrations of 0.12 to 8 µg/ml Long Dilution Sequence and 0.12 – 2 µg/ml 5-Dilution Breakpoint Sequence, for Enterococcus faecium and Staphylococcus spp., to the test panel.
The Gram-positive organisms which may be used for Synercid susceptibility testing in this panel are:
- Enterococcus faecium (vancomycin-resistant and multi-drug resistant strains only) .
- Staphylococcus aureus (methicillin-susceptible strains only)
MicroScan® Synergies plus" Gram-Positive MIC/Combo Panels, utilizing both the MicroScan® Rapid Fluorogenic Identification and Dried Overnight Antimicrobial Susceptibility Testing (AST) technologies, 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 enterococci and staphylococci.
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 Synergies plus™ Pos Broth, after inoculation with a standardized suspension of the organism. After incubation in the WalkAway® SI, or equivalent, for 4.5 - 18 hours, the minimum inhibitory concentration (MIC) for the test organism is read by determining the lowest antimicrobial concentration showing inhibition of growth.
The provided text describes the 510(k) submission for the MicroScan® Synergies plus™ Gram-Positive MIC/Combo Panels with Synercid, which is a device used to determine antimicrobial agent susceptibility.
Here's an analysis of the acceptance criteria and the study that proves the device meets them, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criterion | Reported Device Performance |
|---|---|
| Overall Essential Agreement with frozen Reference panel | 97.4% (for the Long Dilution Sequence) |
| Instrument Reproducibility (for Synercid with Turbidity inoculum preparation method and WalkAway® SI System or equivalent) | Acceptable reproducibility and precision |
| Quality Control Testing (for MicroScan® Synergies plus™ Gram-Positive MIC/Combo Panel with Synercid) | Acceptable results |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: The text states that "The external validation was conducted with fresh and stock Efficacy isolates and stock Challenge strains." However, the exact number of isolates or strains used for the test set is not explicitly provided.
- Data Provenance: The study involved "external validation," implying that the data was collected from a source external to the device manufacturer's core development environment. The origin of the data (e.g., specific countries or regions) is not mentioned. The isolates included "fresh and stock Efficacy isolates" and "stock Challenge strains," indicating a mix of types that likely included both clinical isolates and characterized strains. The study design sounds retrospective in the sense that existing "stock" strains and isolates were used, but the testing itself was performed prospectively with the device.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
The text does not explicitly state the number of experts or their qualifications used to establish the ground truth for the test set. It mentions a comparison with a "frozen Reference panel" and "Expected Results determined prior to the evaluation" for challenge strains. This implies that the ground truth was established by a reference method, likely involving expert consensus or a gold standard test, but the details of this process are not described.
4. Adjudication Method for the Test Set
The text does not describe any specific adjudication method (e.g., 2+1, 3+1) for the test set. The ground truth was established through comparison with a "frozen Reference panel" and "Expected Results," which are likely predetermined values based on established methods, rather than an expert adjudication process for each individual test result in the context of this type of device.
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 type of study is typically associated with medical imaging or diagnostic devices where human readers interpret results, and the AI assists in that interpretation. For Antimicrobial Susceptibility Testing (AST) panels, the device itself provides the result, and performance is measured against a reference method rather than human interpretation alongside the device.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, a standalone performance evaluation was done. The "overall Essential Agreement of 97.4%" was reported for the MicroScan® Synergies plus™ Gram-Positive Panel when compared with the frozen Reference panel. This directly assesses the device's accuracy in determining MIC values without human intervention in the result generation or interpretation process beyond loading the samples and the machine reading the results. The panels are read by "MicroScan® Instrumentation," indicating automated reading.
7. The Type of Ground Truth Used
The ground truth used was primarily a reference method comparison. Specifically:
- For efficacy isolates, the device's performance was compared to a "frozen Reference panel." This "Reference panel" itself would have been established using a recognized gold standard method for antimicrobial susceptibility testing.
- For challenge strains, the device's results were compared to "Expected Results determined prior to the evaluation." These "Expected Results" would also be derived from established reference methods for those specific strains.
The text specifies that the comparison was "as defined in the FDA document 'Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA', dated February 5, 2003," which outlines the standard for such reference methods.
8. The Sample Size for the Training Set
The document does not provide information regarding the sample size used for a training set. This is a 510(k) summary focused on performance validation against a predicate device, not on the underlying development or training of an algorithm (if one were used in a way that required a distinct training set, which is less common for traditional MIC panels compared to more complex AI systems).
9. How the Ground Truth for the Training Set Was Established
Since information about a separate "training set" and its sample size is not provided, the method for establishing its ground truth is also not described. For this type of AST device, the "training" may implicitly refer to the development and optimization of the panel formulations and reading algorithms, which would have relied on general microbiological principles and possibly internal datasets, but not necessarily a formally defined "training set" in the context of a public submission like this.
§ 866.1645 Fully automated short-term incubation cycle antimicrobial susceptibility system.
(a)
Identification. A fully automated short-term incubation cycle antimicrobial susceptibility system is a device that incorporates concentrations of antimicrobial agents into a system for the purpose of determining in vitro susceptibility of bacterial pathogens isolated from clinical specimens. Test results obtained from short-term (less than 16 hours) incubation are used to determine the antimicrobial agent of choice to treat bacterial diseases.(b)
Classification. Class II (special controls). The special control for this device is FDA's guidance document entitled “Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA.”