(77 days)
VITEK® 2 AST-Gram Negative Minocycline is designed for antimicrobial susceptibility testing of Gram Negative bacilli 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 AST-Gram Negative Minocycline is a quantitative test. Minocycline has been shown to be active against most strains of the microorganisms listed below, according to the FDA label for this antimicrobial.
Active in vitro and in clinical infections: Acinetobacter spp.
Klebsiella (Enterobacter) aerogenes Escherichia coli Klebsiella spp.
The VITEK® 2 Gram-negative Susceptibility Card is intended for use with the VITEK® 2 Systems in clinical laboratories as an in vitro test to determine the susceptibility of clinically significant aerobic Gram-negative bacilli to antimicrobial agents when used as instructed.
The VITEK® 2 AST Cards are essentially miniaturized versions of the doubling dilution technique for determining the minimum inhibitory concentration (MIC) microdilution methodology.
The 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 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 antimicrobial contained on the card.
Based on the provided text, here's an analysis of the acceptance criteria and the study that proves the device meets them:
1. A table of acceptance criteria and the reported device performance
| Acceptance Criteria (from FDA Guidance Document) | Reported Device Performance (VITEK® 2 AST-GN Minocycline) |
|---|---|
| Overall Essential Agreement (EA) with CLSI broth microdilution reference method | 97.0% |
| Overall Category Agreement (CA) with CLSI broth microdilution reference method | 93.7% |
| Reproducibility and Quality Control results | Acceptable |
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
The text states an "external evaluation was conducted with fresh and stock clinical isolates, as well as a set of challenge strains." While it doesn't provide a specific numerical sample size for the test set, it indicates the types of strains used.
The data provenance is not explicitly mentioned regarding the country of origin. However, the use of "fresh and stock clinical isolates" suggests a prospective or a mix of prospective and retrospective collection of clinical samples. "Challenge strains" are typically laboratory-prepared or well-characterized strains used for validation.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
This section is not applicable as the device (VITEK® 2 AST-GN Minocycline) is an automated system for antimicrobial susceptibility testing, and the ground truth is established by a reference laboratory method (CLSI broth microdilution), not by human experts interpreting images or assay results in a subjective manner.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
This section is not applicable. Adjudication methods like 2+1 or 3+1 are typically used when multiple human readers are involved in subjective interpretation, and disagreements need to be resolved. In this case, the reference method (CLSI broth microdilution) provides a quantitative result, and the device's performance is compared directly to it, not through a process of expert adjudication.
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
This section is not applicable. The VITEK® 2 AST-GN Minocycline is an automated antimicrobial susceptibility testing system. It determines susceptibility without human interpretation in the loop in the same way a human reader would. Therefore, a multi-reader, multi-case study comparing human readers with and without AI assistance is not relevant for this type of device.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Yes, a standalone performance evaluation was done. The VITEK® 2 AST-GN Minocycline is described as a "Fully Automated Short-Term Incubation Cycle Antimicrobial Susceptibility System." The study explicitly compares its performance (97.0% Essential Agreement, 93.7% Category Agreement) directly against the CLSI broth microdilution reference method. This comparison assesses the algorithm's performance in isolation from human intervention in the interpretation process.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
The ground truth used was the CLSI broth microdilution reference method, which is a widely accepted laboratory standard for determining minimum inhibitory concentrations (MICs) of antimicrobials. This is a quantitative, laboratory-based measurement.
8. The sample size for the training set
The text does not explicitly state the sample size for the training set. It only mentions the "external evaluation" for performance testing. Typically, information about training sets for medical devices, particularly those with complex algorithms, is detailed more extensively in the full submission, but it's not present in this summary.
9. How the ground truth for the training set was established
The text does not explicitly state how the ground truth for the training set was established. Assuming a similar methodology to the test set, it would likely involve the CLSI broth microdilution reference method. However, without specific information, this remains an assumption. The summary focuses on the validation study's ground truth.
§ 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.”