(102 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°C +/- 1°C, 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 Gentamicin Synergy Screen, at a concentration of 500 µg/ml, for enterococci, to the test panel.
The gram-positive organisms which may be used for Gentamicin Synergy Screen susceptibility testing in this panel are:
Enterococcus species
MicroScan® Synergies plus''' Gram-Positive MIC/Combo Panels, utilizing both the MicroScan® Rapid Fluorogenic Identification and Dried Overnight Antimicrobial Susceptibility Tcsting (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, System, 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.
Acceptance Criteria and Device Performance Study for MicroScan® Synergies plus™ Gram-Positive MIC/Combo Panels with Gentamicin Synergy Screen
This document describes the acceptance criteria and the study that proves the MicroScan® Synergies plus™ Gram-Positive MIC/Combo Panels with Gentamicin Synergy Screen device meets its acceptance criteria.
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria Category | Acceptance Criteria (Threshold) | Reported Device Performance |
|---|---|---|
| Overall Categorical Agreement (Reference Panel Comparison) for Gentamicin Synergy Screen | Acceptable performance | 97.0% |
| Instrument Reproducibility | Acceptable reproducibility and precision | Demonstrated acceptable reproducibility and precision |
| Quality Control Testing | Acceptable results | Demonstrated acceptable results |
Note: The document does not specify a numerical threshold for "acceptable performance" for categorical agreement, reproducibility, or quality control. However, the stated 97.0% categorical agreement is reported as having demonstrated "acceptable performance."
2. Sample Size and Data Provenance
The study utilized two types of strains:
- Efficacy isolates: "fresh and stock" isolates.
- Challenge strains: "stock" strains.
The exact numerical sample size for both efficacy isolates and challenge strains is not explicitly stated in the provided text.
The data provenance is not explicitly mentioned (e.g., country of origin). The study design appears to be retrospective, as it used "stock efficacy isolates and stock challenge strains," and the evaluation was compared against "Expected Results determined prior to the evaluation" for challenge strains, suggesting these were pre-existing collections rather than prospectively collected clinical samples.
3. Number of Experts and Qualifications for Ground Truth
The document does not specify the number of experts used to establish the ground truth for the test set, nor does it provide their qualifications.
4. Adjudication Method for the Test Set
The document does not describe any adjudication method (e.g., 2+1, 3+1) for the test set.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
A multi-reader multi-case (MRMC) comparative effectiveness study was not conducted or described. The study focuses on the performance of the device itself against a reference standard, not on human reader performance with or without AI assistance.
6. Standalone Performance Study
Yes, a standalone performance study was conducted. The "external validation" compared the new device's performance directly with a "frozen Reference Panel" and "Expected Results." This assesses the algorithm/device's performance without human intervention as a primary part of the comparison.
7. Type of Ground Truth Used
The ground truth for the external validation study was established using two methods:
- Frozen Reference Panel: The device's performance was compared against a "frozen Reference Panel," which serves as a gold standard for antimicrobial susceptibility testing.
- Expected Results: For challenge strains, the device's performance was compared to "Expected Results determined prior to the evaluation," implying a pre-established ground truth for these specific strains.
The reference panel is described as a "miniaturization of the broth dilution susceptibility test."
8. Sample Size for the Training Set
The document does not specify the sample size used for the training set. The descriptions provided primarily concern the validation/test phase of the device.
9. How Ground Truth for the Training Set Was Established
The document does not describe how the ground truth was established for any potential training set. The provided text focuses on the external validation of the device against established reference methods.
§ 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.”