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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.
This particular submission is for the addition of the antimicrobial Amoxicillin/Clavulanic Acid at concentrations of 0.015/0.008 to 16/8 mcg/ml to the test panel
The organisms which may be used for Amoxicillin/ Clavulanic Acid susceptibility testing in this panel are:
Streptococcus pneumoniae

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 inculation, panels are incubated for 20 - 24 hours at 35°C +/- 1°C in a non-CO2 incubator, and read visually 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 ul 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 (MC) for the test organism is manually read by observing the lowest antimicrobial concentration showing inhibition of growth.

The MicroScan® MICroSTREP plus™ Panel is intended to determine bacterial susceptibility to Amoxicillin/Clavulanic Acid, specifically for Streptococcus pneumoniae. The device is a microdilution minimum inhibitory concentration (MIC) panel that provides quantitative and/or qualitative antimicrobial agent susceptibility readings.

1. Acceptance Criteria and Reported Device Performance

Essential Agreement is defined as the agreement between the MIC obtained by the test device and the MIC obtained by the reference method (NCCLS frozen Reference Panel) within ±1 doubling dilution.

2. Sample Size and Data Provenance

The study used "fresh and stock Efficacy isolates and stock Challenge strains" for the external evaluation. No specific numerical sample size is provided for the test set.

The provenance of data is not explicitly stated in terms of country of origin. The study was a retrospective evaluation comparing the device's performance to an established reference method.

3. Number and Qualifications of Experts for Ground Truth

The document does not explicitly state the number or qualifications of experts used to establish the ground truth for the test set. The ground truth was established by an "NCCLS frozen Reference Panel," which implicitly suggests standardized and expert-derived values based on established guidelines.

4. Adjudication Method

The adjudication method is not explicitly mentioned. However, the comparison was made against a "NCCLS frozen Reference Panel," implying a predefined and standardized ground truth rather than a real-time adjudication process by experts on a case-by-case basis.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

There is no indication that a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was conducted. The evaluation focuses on the device's performance against a reference panel, not on the improvement of human readers with AI assistance. The reading of the panels is described as "manually read by observing the lowest antimicrobial concentration showing inhibition of growth," implying a human-in-the-loop, but without comparison to AI assistance.

6. Standalone Performance Study

A standalone performance study was conducted. The "external evaluation was conducted with fresh and stock Efficacy isolates and stock Challenge strains" to confirm the acceptability of the proposed MICroSTREP plus™ Panel by comparing its performance with an NCCLS frozen Reference panel. This directly measures the algorithm's performance (the MicroScan panel's ability to produce accurate MICs) in isolation.

7. Type of Ground Truth Used

The ground truth used was based on an NCCLS frozen Reference Panel. This represents a standardized, expert-developed reference method for antimicrobial susceptibility testing, which serves as the gold standard for comparison in such studies.

8. Sample Size for the Training Set

The document does not provide information about a separate training set or its sample size. The focus is on the performance of the device against the reference standard. Given the nature of a microdilution panel (a physical product with pre-determined reagent concentrations), it's unlikely to have a "training set" in the context of machine learning algorithms. The development of such panels relies on extensive microbiological research and standardization.

9. How Ground Truth for the Training Set was Established

As there is no explicit mention of a training set in the context of the device's development as an AI/ML product, this information is not applicable. The device relies on a chemical and biological methodology for determining susceptibility, not a machine learning model that requires a training phase with labeled data. The "ground truth" for the overall methodology would stem from established microbiological principles and NCCLS (now CLSI) guidelines.

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