(35 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 oxacillin, at concentrations of 0.03 to 8 ug/ml Long Dilution Sequence for S. aureus and S. lugdunensis, and 0.03 - 2 ug/ml 7-Dilution MIC Dilution Sequence, and 0.12 -- 2 ug/ml 5-Dilution Breakpoint Sequence, for all Staphylococcus species, to the test panel.
The Gram-positive organisms which may be used for oxacillin susceptibility testing in this panel are:
. Staphylococcus species
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 Synergics 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 document describes the 510(k) submission for the MicroScan® Synergies plus™ Gram-Positive MIC/Combo Panels with the addition of oxacillin, intended for antimicrobial susceptibility testing.
Here's an analysis based on your requested information:
1. Table of Acceptance Criteria and Reported Device Performance
| Parameter | Acceptance Criteria (Implicit for AST systems per FDA guidance) | Reported Device Performance (Essential Agreement) |
|---|---|---|
| Overall Essential Agreement | Not explicitly stated but typically 90% or higher | 97.1% |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: Not explicitly stated as a number. The study mentions "fresh and stock Efficacy isolates and stock Challenge strains." However, the exact count of isolates and strains used for external validation is not provided.
- Data Provenance: The document does not specify the country of origin. It indicates the study was an "external validation."
- Retrospective or Prospective: Retrospective, as "stock Efficacy isolates and stock Challenge strains" are used, implying pre-existing samples.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
- This information is not provided in the document. The reference panel is described as a "frozen Reference Panel" and "Expected Results," but the process for establishing the ground truth for this reference is not detailed.
4. Adjudication Method for the Test Set
- This information is not provided in the document. The comparison is made against a "frozen Reference Panel" and "Expected Results," which implies a single, established ground truth rather than a process requiring adjudication among multiple experts for the test set.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done
- No, an MRMC comparative effectiveness study was not done. This study focuses on the performance of an automated system (MicroScan® Synergies plus™ panels) compared to a reference method, not on human reader performance with or without AI assistance. The document mentions that the AST portions can be read visually, but the primary validation is for the automated instrument reading.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
- Yes, a standalone performance evaluation was done. The study explicitly states that the "MicroScan® Synergies plus™ Gram-Positive MIC/Combo Panel demonstrated substantially equivalent performance when compared with a frozen Reference Panel." The assessment is of the device's ability to determine susceptibility, which is an automated measurement, even though visual reading is also possible.
7. The Type of Ground Truth Used
- The ground truth was established by a "frozen Reference Panel" and "Expected Results." For antimicrobial susceptibility testing (AST) systems, this typically involves a standardized reference broth microdilution method, which is considered the gold standard.
8. The Sample Size for the Training Set
- The document does not provide information regarding a separate training set. The study focuses on "external validation" with "fresh and stock Efficacy isolates and stock Challenge strains," which serve as the test set. For AST systems, the "training" aspect is more about the development and optimization of the panel's design and interpretation rules, often involving a large internal collection of characterized strains, rather than a distinct "training set" in the machine learning sense for the final validation study.
9. How the Ground Truth for the Training Set was Established
- As no specific training set is detailed, the method for establishing its ground truth is not provided. If an internal development set was used, its ground truth would have likely been established through similar reference methods as the validation set.
§ 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.”