(26 days)
To determine bacterial antimicrobial agent susceptibility
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℃ +/- 1℃ in a non-CO2 incubator, and read visually according to the Package Insert. Additionally, the panels may be incubated in and read by a MicroScan® WalkAway instrument.
This particular submission is for the addition of instrument read capability of the antimicrobial Clarithromycin, at concentrations of 0.06 - 2 mcg/ml on the MicroScan MICroSTREP plus® Panel.
The organisms which may be used for Clarithromycin susceptibility testing on this panel are:
Streptococcus pneumoniae
Streptococcus pyogenes
Streptococcus agalactiae
Streptococci (Groups C, F, G)
viridans group streptococci
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 ℃ in a non-CO2 incubator, and read according to the Package Insert.
The antimicrobial susceptibility tests are miniaturizations of the broth dilution susceptibility test. 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) and buffered with 50 mM HEPES, after inoculation of the broth with a standardized suspension of the organism in saline. 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. Additionally, the panels may be incubated in and read by a MicroScan® WalkAway instrument.
Here's an analysis of the provided text regarding the acceptance criteria and the study that proves the device meets those criteria:
Device: MicroScan MICroSTREP plus® Panel with Clarithromycin (0.06 – 2 mcg/ml)
Intended Use: To determine bacterial antimicrobial agent susceptibility, specifically for Clarithromycin against aerobic streptococci, including Streptococcus pneumoniae. This submission focuses on adding instrument-read capability using the MicroScan® WalkAway instrument.
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Inferred from "acceptable performance") | Reported Device Performance (Clarithromycin, instrument read vs. Expected Result) |
|---|---|
| Overall Essential Agreement (EA) | 98.6% |
| Reproducibility and Precision | Acceptable |
| Quality Control (QC) | Acceptable |
Note: The document explicitly states "acceptable performance with an overall Essential Agreement of 98.6%". The "acceptable" for reproducibility, precision, and QC implies these were also acceptance criteria, though no numerical thresholds are given in the provided text.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size (Test Set): Not explicitly stated. The document mentions "external evaluation was conducted with stock and CDC Challenge strains," but the specific number of strains or isolates tested is not provided.
- Data Provenance: The study was an "external evaluation." While the specific country is not mentioned, the manufacturer (Dade Behring Inc.) is based in the USA, and the FDA submission is to the US regulatory body, suggesting the evaluation would align with US standards and likely involve US-based laboratories or strains. The data appears to be prospective in nature, as it was designed to "confirm the acceptability of the proposed instrument read method" by comparing it to "Expected Results determined before the evaluation."
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications
This information is not provided in the given text. The "Expected Result" is mentioned as the comparator, and it was "generated on a CLSI frozen Reference Panel," but the human involvement in establishing these "Expected Results" or "ground truth" is not detailed.
4. Adjudication Method for the Test Set
This information is not provided in the given text. While an "Expected Result" was used, the method by which this ground truth was confirmed or adjudicated (e.g., beyond the CLSI reference panel itself) is not described.
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 is focused on the performance of the instrument-read method for antimicrobial susceptibility testing, comparing it to an "expected result" from a reference method, not on human reader performance with or without AI assistance.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, a standalone performance study was done. The entire premise of the submission is to demonstrate the performance of the MicroScan® WalkAway instrument (an automated system, essentially an algorithm/device only) in reading the MICroSTREP plus® Panel with Clarithromycin. It compares the "instrument read results" to a predefined "Expected Result," implying an algorithm-only evaluation. The primary comparison is the instrument reading versus the CLSI frozen Reference Panel, which serves as the independent standard. The original method was "manually read by observing the lowest antimicrobial concentration showing inhibition of growth," but the study explicitly focuses on the "addition of instrument read capability."
7. The Type of Ground Truth Used
The ground truth used was based on an "Expected Result generated on a CLSI frozen Reference Panel." This indicates a well-established, standardized reference method, likely involving expert consensus and adherence to Clinical and Laboratory Standards Institute (CLSI) guidelines, which are recognized standards for antimicrobial susceptibility testing.
8. The Sample Size for the Training Set
The document does not provide information regarding a distinct "training set." The study described is an "external evaluation" conducted to confirm acceptability, implying a validation or test set. For an AST system, the "training" analogous to machine learning often happens during the initial development and optimization of the instrument's reading algorithms, using various characterized strains and concentration ranges. This information is typically proprietary and not part of the 510(k) summary for a post-development validation.
9. How the Ground Truth for the Training Set Was Established
As no specific training set is mentioned in the context of this 510(k) summary, the method for establishing its ground truth is not described. If "training" implicitly refers to the initial development of the instrument's reading capabilities, it would have involved a similar process as the ground truth for the test set, likely using CLSI reference methods and expert interpretation to teach the instrument to accurately "read" MIC values.
§ 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).