(213 days)
VITEK® 2 Gram Negative Doripenem is designed for antimicrobial susceptibility testing of Gram negative microorganisms and is intended for use with the VITEK 2 and VITEK 2 Compact Systems as a laboratory aid in the determination of in vitro susceptibility to antimicrobial agents. VITEK 2 Gram Negative is a quantitative test. Doripenem has been shown to be active against the microorganisms listed below according to the FDA label for the antimicrobial.
Active in vitro and in clinical infections: Acinetobacter baumannii Escherichia coli Klebsiella pneumoniae Proteus mirabilis Pseudomonas aeruginosa
Active in vitro but clinical significance unknown: Citrobacter freundii Enterobacter cloacae Enterobacter aerogenes Klebsiella oxytoca Serratia marcescens
The VITEK® 2 Antimicrobial Susceptibility Test (AST) is intended to be used with the VITEK® 2 and VITEK® 2 Compact Systems for the automated quantitative or qualitative susceptibility testing of isolated colonies for the most clinically significant aerobic gramnegative bacilli, Staphylococcus spp., Enterococcus spp., Streptococcus agalactiae, and S. pneumoniae.
The antimicrobial presented in VITEK 2 AST Cards is in concentrations equivalent by efficacy to standard method concentrations in mog/ml. The VITEK 2 AST Cards are essentially miniaturized versions of the doubling dilution technique for determining the minimum inhibitory concentration (MIC) microdilution methodology.
The bacterial isolate to be tested is diluted to a standardized concentration in 0.45 - 0 .50% saline before being used to rehydrate the antimicrobial medium within the card. The VITEK 2 System automatically fills, seals and places the card into the incubator/reader. The VITEK 2 Compact has a manual filling and sealing operation. The VITEK 2 monitors the growth of each well in the card over a defined period of time (up to 18 hours). At the completion of the incubation cycle, a report is generated that contains the MIC value along with the interpretive category result for each antibiotic contained on the card.
Here's an analysis of the provided text, extracting the requested information about the device's acceptance criteria and the supporting study:
VITEK® 2 Gram Negative Doripenem - Acceptance Criteria and Study Details
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (What must be achieved) | Reported Device Performance (What was achieved) |
|---|---|
| Substantially equivalent performance to CLSI broth microdilution reference method, as defined in FDA Class II Special Controls Guidance Document. | Demonstrated substantially equivalent performance. |
| Acceptable overall Category Agreement. | 97.9% overall Category Agreement. |
| Acceptable Reproducibility. | Demonstrated acceptable results. |
| Acceptable Quality Control. | Demonstrated acceptable results. |
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Sample Size: Not explicitly stated as a single number for total isolates. The study refers to "fresh and stock clinical isolates and stock challenge strains." This suggests a diverse collection, but the exact number is missing.
- Data Provenance: The study was an "external evaluation," implying testing conducted outside of bioMérieux's internal labs. There is no explicit mention of the country of origin, but the submission is to the FDA (USA), and the CLSI (Clinical and Laboratory Standards Institute) is a US-based organization, suggesting a US-centric context for the data, or at least data compliant with US standards. The isolates were a mix of "fresh and stock clinical isolates and stock challenge strains," indicating a combination of prospective and retrospective (for stock clinical isolates and challenge strains) data.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
- Number of Experts: Not specified.
- Qualifications of Experts: Not specified. It's implied that the CLSI broth microdilution reference method is the gold standard, and its execution would typically involve trained microbiologists or laboratory personnel experienced in performing and interpreting these reference methods.
4. Adjudication Method for the Test Set
- Adjudication Method: Not explicitly stated. The comparison is directly between the VITEK® 2 system and the CLSI broth microdilution reference method. This direct comparison usually implies that the CLSI method's result is taken as the definitive ground truth without a separate expert adjudication process for discordant results, beyond potentially re-testing by the reference method itself if initial results were unclear.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- MRMC Study Done: No. This device is an automated antimicrobial susceptibility testing (AST) system, not an imaging or diagnostic device that typically involves human readers interpreting cases. Therefore, an MRMC study comparing human readers with and without AI assistance is not applicable here. The comparison is between an automated system and a reference microbiology method.
6. Standalone (Algorithm Only) Performance
- Standalone Performance Done: Yes. The entire study focuses on the "standalone" performance of the VITEK® 2 Gram Negative Doripenem system. The system automatically performs the test, interprets the growth, and generates the MIC value and interpretive category without human intervention during the test run or interpretation beyond initial setup and loading. The reported 97.9% overall Category Agreement is a measure of this standalone performance against the reference method.
7. Type of Ground Truth Used
- Ground Truth Type: Expert consensus through a reference method. Specifically, the "CLSI broth microdilution reference method," as defined in the FDA Class II Special Controls Guidance Document. This is considered the gold standard for antimicrobial susceptibility testing.
8. Sample Size for the Training Set
- Training Set Sample Size: Not explicitly stated. The document describes the external evaluation for validation (test set), but does not detail the size or nature of the data used to initially train or develop the VITEK 2 AST card and its interpretive algorithms.
9. How Ground Truth for the Training Set Was Established
- Ground Truth for Training Set Establishment: Not explicitly detailed in the provided summary. However, for AST systems, the ground truth for training (or development/calibration) would similarly be established by comparing the device's readings against established reference methods, like the CLSI broth microdilution method, during the development phase. This process calibrates the system's interpretive algorithms to accurately reflect the true MIC values and interpretive categories.
§ 866.1645 Fully automated short-term incubation cycle antimicrobial susceptibility system.
(a)
Identification. A fully automated short-term incubation cycle antimicrobial susceptibility system is a device that incorporates concentrations of antimicrobial agents into a system for the purpose of determining in vitro susceptibility of bacterial pathogens isolated from clinical specimens. Test results obtained from short-term (less than 16 hours) incubation are used to determine the antimicrobial agent of choice to treat bacterial diseases.(b)
Classification. Class II (special controls). The special control for this device is FDA's guidance document entitled “Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA.”