(57 days)
VITEK® 2 Gram Negative Gatifloxacin is designed for antimicrobial susceptibility testing of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Acinetobacter lwoffii, Citrobacter koseri, C. freundii, Enterobacter aerogenes, E. cloacae, Klebsiella oxytoca, Morganella morganii, and Proteus vulgaris. It is intended for use with the VITEK® 2 System as a laboratory aid in the determination of in vitro susceptibility to antimicrobial agents.
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% 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 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 a summary of the acceptance criteria and study details for the VITEK® 2 Gram Negative Gatifloxacin, based on the provided document:
Acceptance Criteria and Device Performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Overall Essential Agreement (compared to NCCLS reference agar dilution method) | 99.7% |
| Reproducibility | Acceptable results (specific percentage not given) |
| Quality Control | Acceptable results (specific percentage not given) |
Note: The document only explicitly states the acceptance criterion for "Overall Essential Agreement" as acceptable performance. The criteria for reproducibility and quality control are not quantified but stated as "acceptable results."
Study Information
1. Sample Size Used for the Test Set and Data Provenance:
- Sample Size: Not explicitly stated as a single number. The study utilized "fresh and stock clinical isolates and stock challenge strains."
- Data Provenance: Not specified, but generally, clinical isolates would be prospective or retrospective, and stock challenge strains are typically laboratory-maintained. The country of origin is not mentioned.
2. Number of Experts Used to Establish the Ground Truth for the Test Set and the Qualifications of Those Experts:
- This information is not provided in the document. The ground truth method (NCCLS reference agar dilution method) is a standardized laboratory procedure, not typically established by human experts in the same way an image interpretation might be.
3. Adjudication Method for the Test Set:
- This information is not applicable/provided. The NCCLS agar dilution method is a distinct scientific procedure, not subject to human adjudication in the typical sense.
4. 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:
- No, an MRMC comparative effectiveness study was not done. This device is an automated antimicrobial susceptibility testing system, not an AI system designed to assist human readers in interpretation.
5. If a Standalone (i.e. algorithm only without human-in-the-loop performance) Was Done:
- Yes, a standalone performance study was done. The VITEK® 2 system is fully automated and designed to provide results without human intervention beyond sample preparation and loading. The study compares its automated performance to the reference method.
6. The Type of Ground Truth Used:
- NCCLS reference agar dilution method. This is a recognized standard laboratory method for determining minimum inhibitory concentrations (MICs) of antimicrobial agents.
7. The Sample Size for the Training Set:
- This information is not provided and is likely not applicable in the context of this device. The VITEK® 2 system relies on established biochemical and growth principles for detection, not on a machine learning model that requires a "training set" in the traditional sense. The "training" would be tied to the development and validation of the card's antimicrobial concentrations and the system's growth monitoring algorithms.
8. How the Ground Truth for the Training Set Was Established:
- This information is not provided and is likely not applicable for the reasons stated above for sample size. The ground truth for the underlying principles of the VITEK® 2 system would be based on fundamental microbiology and pharmacology, and the design of the miniaturized doubling dilution methodology.
§ 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.”