(16 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. Additionally, the panels may be incubated in and read by a MicroScan® WalkAway instrument.
This particular submission is for the addition of instrument read capability of the antimicrobial Levofloxacin, at concentrations of 0.12 to 16 mcg/ml on the MicroScan MICroSTREP plus® Panel.
The organisms which may be used for Levofloxacin susceptibility testing on this panel are:
Streptococcus pneumoniae (including penicillin-resistant strains) Streptococcus pyogenes Streptococcus (Group C/F) Streptococcus (Group G) Streptococcus agalactiae Viridans group streptococci
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 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. Additionally, the panels may be incubated in and read by a MicroScan® WalkAway instrument.
Acceptance Criteria and Study Details for MicroScan MICroSTREP plus® Panel (K062276)
Here's a breakdown of the acceptance criteria and study details for the MicroScan MICroSTREP plus® Panel as presented in the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Success Metric) | Reported Device Performance (Levofloxacin Instrument Read) |
|---|---|
| Overall Essential Agreement | 100% Essential Agreement |
| Instrument reproducibility | Acceptable reproducibility and precision |
| Quality Control testing | Acceptable results |
Note: The specific numerical targets for "acceptable" essential agreement, reproducibility, and precision are not explicitly defined in the provided text beyond the statement that the essential agreement should meet the "FDA document 'Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA', dated February 5, 2003."
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: The text mentions "stock and CDC Challenge strains" were used for external evaluations. However, the exact number of strains or individual tests performed is not specified.
- Data Provenance: The data provenance is described as using "stock and CDC Challenge strains." This implies a retrospective data set, likely sourced from culture collections. The country of origin is not explicitly stated, but "CDC Challenge strains" suggests a U.S. origin.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Their Qualifications
The study refers to "Expected Results determined before the evaluation" which were based on a "CLSI frozen Reference Panel." This suggests that the ground truth was established by recognized reference methods and interpreted by experts. However, the number of experts and their specific qualifications are not explicitly stated in the provided text.
4. Adjudication Method for the Test Set
The text indicates that the device's instrument read results were compared with "Expected Results." This implies a comparison against a pre-established ground truth, rather than an adjudication method involving multiple readers for the test set itself. There is no mention of a 2+1, 3+1, or similar adjudication process for the new device's readings.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
There is no mention of a Multi-Reader Multi-Case (MRMC) comparative effectiveness study being performed. The study focuses on comparing the instrument's performance against expected results, not on quantifying the improvement of human readers with AI assistance.
6. Standalone Performance Study
Yes, a standalone performance study was performed (algorithm only without human-in-the-loop performance). The study evaluated the "proposed instrument read method" (MicroScan® WalkAway instrument) for its ability to determine MIC, comparing its results directly with "Expected Results" from a CLSI frozen Reference Panel. This assesses the algorithm's performance independent of human interpretation of the instrument's output.
7. Type of Ground Truth Used
The type of ground truth used was expert consensus / reference method. The "Expected Results" were determined before the evaluation using a "CLSI frozen Reference Panel." The CLSI (Clinical and Laboratory Standards Institute) sets standards for laboratory testing, and their reference panels would be considered a reliable ground truth established through standardized methods and expert consensus.
8. Sample Size for the Training Set
The provided text does not explicitly state the sample size for the training set. The study description focuses on the evaluation of the instrument, not on the development or training of its underlying algorithm.
9. How the Ground Truth for the Training Set Was Established
As the text does not mention a training set or the development process for the algorithm, it does not provide information on how the ground truth for a training set was established.
§ 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).