(69 days)
To determine bacterial antimicrobial agent susceptibility. The MicroScan® MICroSTREP plus™ Panel is used to determine quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of aerobic streptococci, including Streptococcus pneumoniae. After inoculation, panels are incubated for 20 - 24 hours at 35°C +/- 1°C in a non-CO2 incubator, and read visually according to the Package Insert. This particular submission is for the addition of the antimicrobial Gatifloxacin at concentrations of 0.06 to 8 mcg/ml to the test panel. The organisms which may be used for Gatifloxacin susceptibility testing in this panel are; Streptococcus pneumoniae, Streptococcus pyogenes.
The MicroScan® MICroSTREP plus™ Panel is used to determine quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of aerobic streptococci, including Streptococcus pneumoniae. After inoculation, panels are incubated for 20 - 24 hours at 35°C +/- 1°C in a non-CO2 incubator, and read visually according to the Package Insert. The antimicrobial susceptibility tests are miniaturizations of the broth dilution susceptibility test. Various antimicrobial agents are diluted in water, buffer or minute concentrations of broth to concentrations bridging the range of clinical interest. Panels are rehydrated with 115 ul Mueller-Hinton broth supplemented with 2-5% lysed horse blood (LHB) and buffered with 50 mM HEPES, after inoculation of the broth with a standardized suspension of the organism in saline. After incubation in a non-CO2 incubator for 20-24 hours, the minimum inhibitory concentration (MIC) for the test organism is manually read by observing the lowest antimicrobial concentration showing inhibition of growth.
The MicroScan® MICroSTREP plus™ Panel is a device used to determine bacterial susceptibility to antimicrobial agents, specifically Gatifloxacin, for aerobic streptococci, including Streptococcus pneumoniae and Streptococcus pyogenes.
Here's an analysis of the acceptance criteria and the study that proves the device meets them:
1. Table of Acceptance Criteria and Reported Device Performance:
| Acceptance Criteria (from FDA Draft Guidance, March 8, 2000) | Reported Device Performance |
|---|---|
| Essential Agreement (EA) with NCCLS frozen Reference Panel | Overall 100% for Gatifloxacin |
| Reproducibility of Gatifloxacin testing | Acceptable |
| Quality Control (QC) testing for Gatifloxacin | Acceptable results |
Note: The specific numerical thresholds for "acceptable" reproducibility and QC results are not provided in the summary. The Essential Agreement (EA) typically refers to the percentage of MICs that are within ±1 doubling dilution of the reference method.
2. Sample Size Used for the Test Set and Data Provenance:
- Sample Size: The document mentions "fresh and stock Efficacy isolates and stock Challenge strains" for the external evaluation. However, the exact number of isolates or strains used in the test set is not specified in this summary.
- Data Provenance: The study involved "external evaluation." The country of origin of the data is not specified. The mention of "fresh and stock Efficacy isolates" suggests a mix, and "stock Challenge strains" indicates a controlled set of organisms. It is not explicitly stated whether the study was retrospective or prospective, but given the nature of susceptibility testing and the use of "fresh" isolates, it likely involved a prospective element or a combination of both.
3. Number of Experts Used to Establish Ground Truth and Qualifications:
- Number of Experts: The document does not specify the number of experts involved in establishing the ground truth.
- Qualifications of Experts: The document does not specify the qualifications of any experts involved. The ground truth was established by comparing the device's performance to an "NCCLS frozen Reference Panel," which implicitly suggests the reference panel itself adheres to expert-defined standards.
4. Adjudication Method for the Test Set:
- The document does not specify an adjudication method (such as 2+1 or 3+1). The performance was directly compared to the NCCLS frozen Reference Panel, which served as the gold standard.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
- No, an MRMC comparative effectiveness study was not done in the context of human readers improved by AI assistance. This device is an in-vitro diagnostic (IVD) for antimicrobial susceptibility testing, and the performance assessment focuses on the accuracy of the device itself against a reference method, not on human interpretation or AI assistance.
6. Standalone (Algorithm Only) Performance:
- Yes, a standalone performance study was done. The entire evaluation described is a standalone performance study, as it assesses the performance of the
MicroScan® MICroSTREP plus™ Paneldirectly. The device itself determines the MIC, and the "manual read by observing the lowest antimicrobial concentration showing inhibition of growth" is the output of the "algorithm" equivalent (the visual observation based on the growth pattern). There is no mention of "human-in-the-loop" interaction beyond the standard visual interpretation of the panel incubation results, which is inherent to this type of device.
7. Type of Ground Truth Used:
- The ground truth used was a "NCCLS frozen Reference Panel." This reference panel serves as the accepted gold standard for determining antimicrobial minimum inhibitory concentrations (MICs). The NCCLS (National Committee for Clinical Laboratory Standards, now Clinical and Laboratory Standards Institute - CLSI) establishes standards for susceptibility testing, so a reference panel endorsed by NCCLS represents a highly authoritative and standardized ground truth.
8. Sample Size for the Training Set:
- The document does not provide information regarding a separate "training set" or its size. For IVD devices like this, the development process typically involves internal validation and optimization, but the provided summary focuses on the external performance evaluation against a reference standard. If machine learning or AI models were involved, a training set would be explicitly mentioned; however, this device appears to be based on a traditional broth dilution method with visual interpretation.
9. How the Ground Truth for the Training Set Was Established:
- As a separate "training set" is not mentioned and the technology described is not explicitly an AI/ML device, this question is not applicable based on the provided information.
§ 866.1640 Antimicrobial susceptibility test powder.
(a)
Identification. An antimicrobial susceptibility test powder is a device that consists of an antimicrobial drug powder packaged in vials in specified amounts and intended for use in clinical laboratories for determining in vitro susceptibility of bacterial pathogens to these therapeutic agents. Test results are used to determine the antimicrobial agent of choice in the treatment of bacterial diseases.(b)
Classification. Class II (performance standards).