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Thermo Scientific Oxoid Antimicrobial Susceptibility Test Discs are used in the semi-quantitative agar diffusion test method for in vitro susceptibility testing. Used in a diagnostic workflow to aid clinicians in determining potential treatment options for patients suspected of having a microbial infection, these discs are intended to determine susceptibility against microorganisms for which specific drugs have been shown to be active both clinically and in vitro.

The Thermo Scientific Oxoid Aztreonam/Avibactam Disc (30/20 µg) AZA50 is intended to determine susceptibility of Enterobacterales to Aztreonam/Avibactam, as recognized by the FDA Susceptibility Test Interpretive Criteria (STIC). The Thermo Scientific Oxoid Aztreonam/Avibactam Disc (30/20 µg) AZA50 demonstrated acceptable performance to determine susceptibility to Aztreonam/Avibactam against the following microorganisms:

Enterobacterales (Citrobacter freundii complex, Escherichia coli, Enterobacter cloacae complex, Klebsiella pneumoniae, Klebsiella oxytoca, Serratia marcescens, and Proteus mirabilis)

Thermo Scientific Oxoid Aztreonam/Avibactam Disc (30/20 µg) AZA50

The provided FDA 510(k) clearance letter pertains to an Antimicrobial Susceptibility Test Disc (ASTD), specifically the "Thermo Scientific Oxoid Aztreonam/Avibactam Disc (30/20 µg) AZA50". This type of device is a diagnostic tool used in microbiology laboratories to determine how effective certain antimicrobials are against specific microbial infections.

The information typically requested for AI/ML-based medical devices (such as acceptance criteria, ground truth establishment for training/test sets, sample sizes, MRMC studies, etc.) is not directly applicable to this type of traditional in vitro diagnostic device (IVD).

Here's why and what can be extracted from the document:

• Nature of the Device: The Aztreonam/Avibactam Disc is a physical disc impregnated with antimicrobial agents. Its "performance" refers to its ability to accurately measure the zone of inhibition (a clear area around the disk where bacteria do not grow), which then correlates to the susceptibility or resistance of the microorganism to the antibiotic. It's not an AI/ML algorithm that interprets or processes complex images or data in an automated way.
• Acceptance Criteria for ASTDs: For ASTDs, acceptance criteria typically involve demonstrating a high degree of correlation between the zone diameters produced by the disc and the Minimum Inhibitory Concentration (MIC) values obtained by a reference method (e.g., broth microdilution). This often involves:
  • Essential Agreement (EA): The percentage of isolates for which the disc test and the reference method produce results that categorize the isolate into the same interpretive category (Susceptible, Intermediate, Resistant).
  • Category Agreement (CA): A stricter measure, where both the zone diameter and MIC fall within defined ranges for a specific category.
  • Major Discrepancies (MD): When the disc test indicates Susceptible, but the reference method indicates Resistant.
  • Very Major Discrepancies (VMD): When the disc test indicates Resistant, but the reference method indicates Susceptible.
  • Minor Discrepancies (mD): Discrepancies between Intermediate and Susceptible/Resistant categories.
    The FDA expects these discrepancy rates to be below certain thresholds (e.g., VMD < 1.5% to 3.0%, MD < 3.0%).
• Study Design for ASTDs: Studies for ASTDs involve testing a diverse collection of bacterial isolates (both wild-type and resistant strains) with the new disc and a reference method. The "ground truth" is typically the reference method's result (e.g., standard broth microdilution or agar dilution).

Therefore, I cannot provide the requested information in the format tailored for AI/ML devices because the provided document is for a traditional diagnostic device.

However, based on general knowledge of IVD submissions, here's what could be inferred and what the document explicitly states:

Inferences for Traditional IVDs (not explicitly stated in the provided text):

• Acceptance Criteria and Reported Performance (Hypothetical for ASTD):

• Sample Size for Test Set: Typically hundreds to thousands of diverse clinical isolates (e.g., 200-500 isolates per species-drug combination, often more for certain categories like resistant isolates).
  • Data Provenance: Usually a mix of retrospective and prospective clinical isolates from various geographic regions (e.g., multiple clinical sites in the US, Europe, etc.) to ensure diversity in resistance mechanisms and strains.
• Number of Experts for Ground Truth: Not applicable in the context of human "experts" establishing truth from images/clinical data. The "ground truth" is established by a reference laboratory method (e.g., CLSI or ISO standard broth microdilution) performed by trained microbiologists.
• Qualifications of Experts: Trained microbiologists and laboratory technicians following standardized protocols for the reference method.
• Adjudication Method: Not applicable. The reference method is the "truth," and results are compared directly to it.
• Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study: Not applicable to this type of device. There are no human "readers" of an AI output to compare.
• Standalone Performance: The "standalone performance" of the disc is its correlation with the reference method.
• Type of Ground Truth Used: Standardized reference antimicrobial susceptibility testing methods (e.g., broth microdilution or agar dilution) and established FDA Susceptibility Test Interpretive Criteria (STIC).
• Sample Size for Training Set: Not applicable for a traditional ASTD; there's no "training" in the ML sense. The formulation of the disc and preliminary testing would involve screening many isolates, but not in an ML training paradigm.
• How Ground Truth for Training Set was Established: Not applicable.

What the document does tell us:

1. Device Identity: Thermo Scientific Oxoid Aztreonam/Avibactam Disc (30/20 µg) AZA50.
2. Intended Use: Used in the semi-quantitative agar diffusion test method for in vitro susceptibility testing to aid clinicians in determining potential treatment options for patients suspected of having a microbial infection. Specifically, it's intended to determine susceptibility of Enterobacterales to Aztreonam/Avibactam, as recognized by the FDA Susceptibility Test Interpretive Criteria (STIC).
3. Microorganisms for which performance was demonstrated: Enterobacterales (Citrobacter freundii complex, Escherichia coli, Enterobacter cloacae complex, Klebsiella pneumoniae, Klebsiella oxytoca, Serratia marcescens, and Proteus mirabilis).
4. Regulatory Classification: Class II, Product Code JTN, Regulation Number 21 CFR 866.1620 (Antimicrobial Susceptibility Test Disc).
5. Performance Statement: "The Thermo Scientific Oxoid Aztreonam/Avibactam Disc (30/20 µg) AZA50 demonstrated acceptable performance to determine susceptibility to Aztreonam/Avibactam against the following microorganisms:" (followed by the list of microorganisms). This statement implies that the manufacturer successfully met the pre-defined acceptance criteria for performance validation.

In summary, the provided document clears a traditional in-vitro diagnostic device, not an AI/ML powered one, meaning the requested detailed information about AI/ML study methodologies is not present nor relevant for this product.

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