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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°C +/- 1°C 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 Amoxicillin/Clavulanic Acid, at concentrations of 0.015/0.008 to 16/8 mcg/ml on the MicroScan MICroSTREP plus® 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 inoculation, panels are incubated for 20-24 hours at 35°C +/-1°C 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 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 (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 a breakdown of the acceptance criteria and study details based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

2. Sample Size Used for the Test Set and Data Provenance

The text states that the external evaluation was conducted with "stock and CDC Challenge strains." It does not specify the exact number of unique isolates or organisms used in the test set.

The provenance of the data is not explicitly stated in terms of country of origin but implies laboratory-based testing from stock and challenge strains. It is a prospective study comparing the device's performance against expected results.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

The document mentions that the performance was compared with an "expected result generated on a CLSI frozen Reference Panel." While this implies a reference standard, it doesn't specify the number of experts or their qualifications for establishing this "expected result." It refers to a standard reference panel rather than individual expert adjudication for each case.

4. Adjudication Method for the Test Set

The adjudication method is not explicitly a human-expert-based consensus method (e.g., 2+1, 3+1). Instead, the device's instrument read results were compared to an "Expected Result" that was "determined before the evaluation" using a "CLSI frozen Reference Panel." This suggests a pre-established gold standard rather than real-time expert adjudication of each test case.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done

No, an MRMC comparative effectiveness study involving human readers with and without AI assistance was not conducted or described. The study focuses on the performance of the instrument-read method compared to a reference standard.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

Yes, the study describes a standalone performance evaluation. The "MicroScan® WalkAway instrument" (which automates the reading) is being evaluated to determine its "instrument read method" performance compared to an "expected result." This is an algorithm/machine-only performance, as it highlights the instrument's ability to read and interpret the results independently.

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 suggests a highly standardized and validated reference method for determining antimicrobial susceptibility, rather than subjective expert consensus, pathology, or outcomes data.

8. The Sample Size for the Training Set

The document does not specify the sample size for the training set. It describes the external evaluation (test set) but provides no information about how the instrument's algorithm was developed or trained.

9. How the Ground Truth for the Training Set Was Established

The document does not provide information on how the ground truth for the training set (if any) was established. It focuses solely on the performance evaluation of the already developed instrument-read method.

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