(72 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 chloramphenicol, at concentrations of 4 to 16 µg/ml, for enterococci and staphylococci, to the test panel.
The gram-positive organisms which may be used for chloramphenicol susceptibility testing in this panel are:
Staphylococcus aureus
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, 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.
Here's a breakdown of the acceptance criteria and study details based on the provided text for the K063564 510(k) submission:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria | Reported Device Performance (Chloramphenicol) |
|---|---|
| Substantially equivalent performance compared to a frozen Reference Panel, as defined in "Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA", dated February 5, 2003. | Overall Categorical Agreement of 96.1% when compared with the frozen Reference panel. |
| Acceptable reproducibility and precision for chloramphenicol with Turbidity inoculum preparation method and the WalkAway® SI System or equivalent. | Demonstrated acceptable reproducibility and precision. |
| Acceptable Quality Control results for chloramphenicol. | Demonstrated acceptable results. |
2. Sample Size Used for the Test Set and Data Provenance
The text states: "The external validation was conducted with fresh and stock Efficacy isolates and stock Challenge strains." However, the exact number of isolates (sample size) used in the test set is not explicitly provided in the given text.
The data provenance is:
- Country of Origin: Not explicitly stated, but the submission is to the US FDA.
- Retrospective or Prospective: Not explicitly stated, but the phrase "external validation was conducted" suggests a prospective collection or evaluation against an existing reference. The use of "fresh" isolates implies a prospective component.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The text mentions comparison to "Expected Results determined prior to the evaluation" for Challenge strains, and a "frozen Reference panel." This implies a pre-established ground truth, likely based on well-characterized strains and a reference method.
- Number of Experts: The number of experts involved in establishing the ground truth for the reference panel or "Expected Results" is not explicitly stated.
- Qualifications of Experts: The qualifications of any experts involved in establishing the ground truth are not explicitly stated. However, given the nature of antimicrobial susceptibility testing, it's implied that these would be microbiologists or clinical laboratory experts.
4. Adjudication Method for the Test Set
The text compares the device's performance directly to a "frozen Reference panel" and "Expected Results." This implies a direct comparison rather than an adjudication process among multiple readers or interpretations of the device's output. Therefore, an explicit adjudication method like "2+1" or "3+1" is not applicable or described in this context.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size
No, an MRMC comparative effectiveness study involving human readers and AI assistance was not done or described in this 510(k) summary. This device is an automated system for antimicrobial susceptibility testing, not an AI-assisted diagnostic tool for human interpretation of images or data.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, this study is inherently a standalone performance evaluation of the MicroScan® Synergies plus™ Gram-Positive MIC/Combo Panel with chloramphenicol. The device, in conjunction with the WalkAway® SI system, automatically determines the MIC. The performance is compared to a reference standard (frozen reference panel), indicating an assessment of the algorithm's (or system's) output without direct human interpretation being the primary variable.
7. The Type of Ground Truth Used
The ground truth used is a "frozen Reference panel" and "Expected Results" for Challenge strains. This reference panel likely represents the established gold standard method for determining antimicrobial susceptibility, which would typically involve a recognized broth microdilution method read visually by experienced microbiologists or a calibrated instrument.
8. The Sample Size for the Training Set
The text does not provide any information about a specific "training set" or its sample size. This is typical for a traditional microbiology device validation, where the system is designed based on established principles, and then its performance is validated against reference methods, rather than being "trained" in the machine learning sense.
9. How the Ground Truth for the Training Set Was Established
Since no training set is mentioned in the context of machine learning, the question of how its ground truth was established is not applicable here. The device's underlying principles are based on established microbiology methods, and its performance is validated against a reference standard.
§ 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.”