(46 days)
VITEK® 2 Gram Positive Ceftaroline is designed for antimicrobial susceptibility testing of Gram positive 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 Positive Ceftaroline is a quantitative test. Ceftaroline 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 Staphylococcus aureus (including methicillin-susceptible and -resistant isolates) The VITEK® 2 Antimicrobial Susceptibility Test (AST) is intended to be used with the VITEK® 2 Systems for the automated quantitative or qualitative susceptibility testing of isolated colonies for the most clinically significant aerobic gram-negative bacilli, Staphylococcus spp., Enterococcus spp., and clinically significant yeast.
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.
Here's a breakdown of the acceptance criteria and the study details for the VITEK® 2 AST-GP Ceftaroline device, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Metric) | Target | Reported Device Performance |
|---|---|---|
| Overall Essential Agreement (EA) | ≥ 90% (Implicit based on standard AST system guidance) | 97.9% |
| Overall Category Agreement (CA) | ≥ 90% (Implicit based on standard AST system guidance) | 99.2% |
| Reproducibility | Acceptable | Acceptable Results |
| Quality Control | Acceptable | Acceptable Results |
Note: The specific numerical targets for Essential Agreement and Category Agreement are not explicitly stated in the document, but for antimicrobial susceptibility testing (AST) systems, FDA guidance typically expects performance well above 90% for these metrics to demonstrate substantial equivalence.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: Not explicitly stated in terms of an exact number of isolates. The document mentions "fresh and stock clinical isolates, as well as a set of challenge strains." This implies a diverse and representative set of strains, but the specific count is missing.
- Data Provenance: Not explicitly stated. The study was an "external evaluation," which generally means it was conducted independently of the device developer. The geographic origin (e.g., country) is not specified, nor is whether the clinical isolates were retrospective or prospectively collected.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications of Those Experts
- Number of Experts: Not applicable. The ground truth was established by a reference method, not by human experts.
- Qualifications of Experts: N/A
4. Adjudication Method for the Test Set
- Adjudication Method: Not applicable. The comparison was made against a single, established reference method (CLSI broth microdilution); therefore, no adjudication among multiple expert readers was necessary.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- Was it done?: No. This type of study is typically performed for imaging or diagnostic devices where human readers interpret results. The VITEK® 2 system is an automated AST system that provides quantitative and interpretive results directly.
- Effect Size of human reader improvement: N/A
6. Standalone Performance Study (Algorithm only without human-in-the-loop performance)
- Was it done?: Yes. The study directly compared the VITEK® 2 AST-GP Ceftaroline's performance to the CLSI broth microdilution reference method. The VITEK® 2 system operates autonomously to determine MIC values and interpretive categories, so this constitutes a standalone performance evaluation.
7. Type of Ground Truth Used
- Type of Ground Truth: The ground truth was established by the CLSI broth microdilution reference method, incubated at 16-20 hours. This is the gold standard for antimicrobial susceptibility testing.
8. Sample Size for the Training Set
- Sample Size for Training Set: Not explicitly stated. The document focuses on the external evaluation for efficacy, which is analogous to a test set. Information regarding a separate training set used during the development of the VITEK® 2 AST-GP Ceftaroline algorithm is not provided in this summary.
9. How the Ground Truth for the Training Set Was Established
- How Ground Truth for Training Set Was Established: Not explicitly stated. Given that no separate training set details are provided, it's presumed that the development of the VITEK® 2 algorithm would have involved extensive in-house testing and calibration against reference methods, similar to how the final evaluation was conducted. However, the exact process and ground truth source for training (if applicable in a traditional machine learning sense, which may not be directly applicable to this type of device development) are not detailed here.
§ 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.”