(93 days)
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:
VITEK® 2 Gram Positive Erythromycin for Streptococcus pneumoniae is designed for antimicrobial susceptibility testing of Gram positive Streptococcus pneumoniae 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 Erythromycin for Streptococcus pneumoniae is a qualitative test.
This submission is for the addition of an intermediate interpretive criteria.
Ervthromcvin 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: Streptococcus pneumoniae
VITEK® 2 Gram Positive Erythromycin for Streptococcus pneumoniae is designed for antimicrobial susceptibility testing of Streptococus pneumoniae. It 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. 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% 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.
1. Table of Acceptance Criteria and Reported Device Performance
| Metric | Acceptance Criteria (Not explicitly stated, but implied by regulatory guidance) | Reported Device Performance (Category Agreement) |
|---|---|---|
| Overall Category Agreement | Substantially equivalent to CLSI broth microdilution reference method (implied by "acceptable performance" of 98.4%) | 98.4% |
| Reproducibility | Acceptable (implied) | Acceptable |
| Quality Control | Acceptable (implied) | Acceptable |
Note: The document states that the performance must be "substantially equivalent" to the CLSI broth microdilution reference method, as defined in the FDA Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA, Issued Feb. 5, 2003. While specific numerical acceptance criteria (e.g., minimum percentage for category agreement, essential agreement) are often detailed within such guidance documents, they are not explicitly listed in this 510(k) summary. The summary highlights a "98.4% overall Category Agreement" as demonstrating "acceptable performance," implying this met their internal and regulatory expectations.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set: Not explicitly stated as an exact number in the provided text. The text mentions "fresh and stock clinical isolates and stock challenge strains" were used for an "external evaluation." The original 510(k) (K063492) that this submission refers to would contain the detailed sample size.
- Data Provenance: The data was from a retrospective analysis of clinical trial data that was part of the previous 510(k) (K063492). "There was no new clinical data gathered for this 510(k) notification." The country of origin is not specified but implicitly within the US given the submission to the FDA.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications
- Number of Experts: Not specified.
- Qualifications of Experts: Not specified.
4. Adjudication Method for the Test Set
- Adjudication Method: Not specified. The ground truth was established by the "CLSI broth microdilution reference method," which is a standard laboratory procedure, not typically involving human adjudication in the same way as, for example, image interpretation.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- MRMC Study Done: No. This device is an automated antimicrobial susceptibility testing system, not an imaging device requiring human reader interpretation or assistance. Therefore, an MRMC study comparing human readers with and without AI assistance is not applicable.
6. Standalone Performance Study
- Standalone Study Done: Yes. The study focused on the "algorithm only" performance (i.e., the VITEK 2 system) compared to the CLSI reference method. The VITEK 2 System is an automated device designed to provide a result without human intervention for interpretation beyond loading samples and reviewing the final report. The "overall Category Agreement" of 98.4% represents this standalone performance.
7. Type of Ground Truth Used
- Type of Ground Truth: The ground truth used was the CLSI broth microdilution reference method. This is a recognized standard laboratory method for determining minimum inhibitory concentrations (MICs) of antimicrobial agents.
8. Sample Size for the Training Set
- Sample Size for Training Set: Not applicable or specified. This submission is for a software algorithm change to utilize existing FDA breakpoints, re-analyzing previously collected clinical trial data. While the original device (K063492) would have had a development dataset, this specific submission does not involve new training of a machine learning model but rather a modification to how results are interpreted based on established breakpoints. The term "training set" is usually reserved for machine learning models, which is not what is being described here in the conventional sense.
9. How the Ground Truth for the Training Set Was Established
- How Ground Truth for Training Set Was Established: Not applicable or specified for this submission. As mentioned above, this involves a re-analysis of existing data with a modified algorithm to apply FDA breakpoints, not the training of a new model. The ground truth for the original data was established using the CLSI broth microdilution reference method.
§ 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.”