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Mueller Hinton Agar is a standard basal medium intended for in vitro antimicrobial disk diffusion susceptibility testing of isolated colonies of common, rapidly growing bacteria by the Bauer-Kirby method as standardized by the Clinical and Laboratory Standards Institute (CLSI). This product has not been evaluated for gradient diffusion testing.

Mueller Hinton Agar is a standard basal medium intended for in vitro antimicrobial disk diffusion susceptibility testing of isolated colonies of common, rapidly growing bacteria by the Bauer-Kirby method standardized by the Clinical and Laboratory Standards Institute (CLSI). This product has not been evaluated for gradient diffusion testing.

The Bauer-Kirby procedure is based on the diffusion through an agar gel of antimicrobial substances which are impregnated on sterile paper disks. This method employs disks with a sinqle concentration of antimicrobial agent and zone sizes are correlated with minimum inhibitory concentrations. In the test procedure, a standardized suspension of the organism is swabbed over the entire surface of the agar medium. Sterile paper disks impregnated with specified amounts of antibiotic or other antimicrobial agents are then placed on the surface of the inoculated agar medium. The agar medium is incubated at 35+ 2°C for 16-18 hours. The organism will grow as a solid "lawn". The antimicrobial will diffuse outward (in a circle). If the antimicrobial agent has activity against the organism, a circular zone of growth inhibition will result. The zone of inhibition around the paper disk is measured. A determination as to whether the organism is susceptible, intermediate or resistant to the antimicrobial agent is determined by comparing the size of the zone of inhibition to the zone diameter interpretive criteria in the CLSI M100 Standard.

Here's an analysis of the provided information regarding the Mueller Hinton Agar device, structured according to your request:

Acceptance Criteria and Device Performance Study

1. Table of Acceptance Criteria and Reported Device Performance

2. Sample size used for the test set and the data provenance

• Test Set Sample Size: The sample size varies per organism-antimicrobial combination.
  • For most organism-antimicrobial combinations, a total of 72 results were generated (3 sites x 3 separate days x 2 duplicate tests x 2 lots of Mueller Hinton Agar x 2 different manufacturers of antimicrobial disks).
  • For Ceftaroline, High Level Gentamicin, and High Level Streptomycin, a total of 36 results were generated (only one manufacturer of antimicrobial disks available).
  • The total number of individual test results presented are:
    • Escherichia coli ATCC 25922: 972
    • Staphylococcus aureus ATCC 25923: 648
    • Pseudomonas aeruginosa ATCC 27853: 468
    • Enterococcus faecalis ATCC 29212: 72
    • Enterococcus faecalis ATCC 51299: 144
    • Escherichia coli ATCC 35218: 360
• Data Provenance: The study was a "multi-site reproducibility study" conducted with "CLSI recommended quality control organisms from American Type Culture Collection (ATCC)". The document implies it was a prospective study specifically designed for the 510(k) submission. The country of origin for the data is not explicitly stated, but given the submission to the FDA and reference to CLSI standards, it is highly likely to be the USA.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

This type of study (in vitro diagnostic for microbial susceptibility) does not typically involve human experts establishing a "ground truth" for each individual test result in the same way an imaging study would. The ground truth (acceptable range) is established by:

• Antimicrobial-specific FDA drug label: These labels are based on extensive clinical trials and regulatory review, involving many experts in microbiology, pharmacology, and clinical medicine.
• CLSI Standards M100-S24 or M02-A11: These standards are developed by consensus of numerous international experts in clinical microbiology, including microbiologists, infectious disease physicians, and laboratory scientists.
• Therefore, the "ground truth" is derived from a consensus of a large, unnamed group of highly qualified experts in the field of clinical microbiology and infectious diseases, codified in widely accepted standards.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set

Not applicable. This study measures the zone of inhibition, which is a quantitative measurement compared against predefined interpretive criteria (acceptable range). There is no subjective interpretation requiring adjudication by multiple readers for individual test results.

5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

Not applicable. This is an in vitro diagnostic device for antimicrobial susceptibility testing, not an AI-based diagnostic platform for human readers.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done

Yes, this was a standalone performance study of the Mueller Hinton Agar medium itself. The performance was evaluated based on the quantitative measurement of inhibition zones, with the interpretation of these zones determined by established CLSI standards and FDA drug labels, not by a human interpreting a visual output from an AI algorithm.

7. The type of ground truth used (expert concensus, pathology, outcomes data, etc)

The ground truth used is expert consensus and regulatory/scientific standards. Specifically, the acceptable ranges for zone of inhibition measurements are derived from:

• Antimicrobial-specific FDA drug labels.
• CLSI Standards M100-S24 (Performance Standards for Antimicrobial Susceptibility Testing) or M02-A11 (Performance Standards for Antimicrobial Disk Susceptibility Tests). These standards represent the consensus of experts in clinical microbiology.

8. The sample size for the training set

Not applicable. This is not an AI/machine learning device that requires a training set. The study evaluated the intrinsic performance of the agar medium itself.

9. How the ground truth for the training set was established

Not applicable, as there is no training set for this type of device.

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