(220 days)
VITEK® 2 Streptococcus Erythromycin is designed for antimicrobial susceptibility testing of Streptococcus species. VITEK 2 Streptococcus Erythromycin is a quantitative test 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. Erythromycin 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 Streptococcus pneumoniae Streptococcus pyogenes
Active in vitro but clinical significance unknown Viridans group Streptococci
The VITEK® 2 Antimicrobial Susceptibility Test (AST) is intended to be used with the VITEK® 2 System for the automated quantitative or qualitative susceptibility testing of isolated colonies for the most clinically significant aerobic gram-negative bacilli, Staphylococcus spp., Enterococcus spp., Streptococcus spp. and clinically significant yeast.
The VITEK 2 Antimicrobial Susceptibility Test (AST) is intended to be used with the VITEK 2 System for the automated quantitative or qualitative susceptibility testing of isolated colonies for the most clinically significant aerobic gram- negative bacilli, Staphylococcus spp., Enterococcus spp., Streptococcus spp. and clinically significant yeast.
The antimicrobial presented in VITEK 2 AST-ST Cards is in concentrations equivalent by efficacy to standard method concentrations in ug/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 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 an analysis of the VITEK® 2 Streptococcus Erythromycin device based on the provided text, broken down by your requested criteria:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (from FDA Guidance Document) | Reported Device Performance (VITEK® 2 Streptococcus Erythromycin) |
|---|---|
| Overall Essential Agreement with reference method | 97.9% |
| Overall Category Agreement with reference method | 96.7% |
| Reproducibility | Acceptable results |
| Quality Control | Acceptable results |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: Not explicitly stated as a single number. The document mentions "fresh and stock clinical isolates, as well as a set of challenge strains." Without specific numbers, it's impossible to provide an exact sample size for the test set.
- Data Provenance: The study was an "external evaluation." The country of origin is not specified, nor is whether the data was retrospective or prospective. Given it involved "fresh and stock clinical isolates," it implies a mix of prospectively collected (fresh) and retrospectively stored (stock) data.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
- Number of Experts: Not specified.
- Qualifications of Experts: Not specified. The ground truth was established using the "CLSI broth microdilution reference method," which is a laboratory standard rather than expert consensus on interpretation.
4. Adjudication Method for the Test Set
- Adjudication Method: Not applicable or not specified. The ground truth was determined by a standardized laboratory method (CLSI broth microdilution), which does not typically involve adjudication by multiple human experts in the same way an imaging study might.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size
- MRMC Study: No, an MRMC comparative effectiveness study was not done. This device is an automated antimicrobial susceptibility test system, not a diagnostic imaging or interpretive aid that typically involves human readers. The comparison was device vs. a reference laboratory method.
- Effect Size: Not applicable as no MRMC study was performed.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
- Standalone Performance: Yes, the study evaluated the standalone performance of the VITEK® 2 system. The system automatically fills, seals, incubates, reads, and generates a report with MIC values and interpretive categories. The performance metrics (Essential Agreement and Category Agreement) directly reflect the algorithm's accuracy compared to the reference method.
7. The Type of Ground Truth Used
- Type of Ground Truth: The ground truth was established using a laboratory reference method: the "CLSI broth microdilution reference method" incubated at 24 hours.
8. The Sample Size for the Training Set
- Sample Size for Training Set: Not specified. The document describes the "Premarket Notification (510[k]) presents data in support of VITEK® 2 Streptococcus Erythromycin," implying the study data is for validation. Information on the training set used to develop the VITEK® 2 system's algorithms for Erythromycin 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 specified in the provided text.
§ 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.”