(90 days)
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
§ 866.1620 Antimicrobial susceptibility test disc.
(a)
Identification. An antimicrobial susceptibility test disc is a device that consists of antimicrobic-impregnated paper discs used to measure by a disc-agar diffusion technique or a disc-broth elution technique the in vitro susceptibility of most clinically important bacterial pathogens to antimicrobial agents. In the disc-agar diffusion technique, bacterial susceptibility is ascertained by directly measuring the magnitude of a zone of bacterial inhibition around the disc on an agar surface. The disc-broth elution technique is associated with an automated rapid susceptibility test system and employs a fluid medium in which susceptibility is ascertained by photometrically measuring changes in bacterial growth resulting when antimicrobial material is eluted from the disc into the fluid medium. Test results are used to determine the antimicrobial agent of choice in the treatment of bacterial diseases.(b)
Classification. Class II (performance standards).