(19 days)
MicroScan® Synergies plus™ Gram-Negative MIC/Combo Panel is used to determine quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of rapidly growing aerobic and facultative anaerobic Gram-Negative bacilli (Enterobacteriaceae, glucose non-fermenters, and non-Enterobacteriaceae glucose fermenters. After inoculation, panels are read on the WalkAway® SI System or equivalent (upgraded WalkAway® 40 or WalkAway® 96) according to the Package Insert.
This particular submission is for the antimicrobial Cefuroxime on the Synergies plus™ Gram-Negative MIC/Combo Panels.
The Gram-Negative organisms which may be used for Cefuroxime susceptibility testing in this panel are:
Citrobacter spp Escherichia coli Klebsiella oxytoca Morganella morganii Proteus mirabilis Providencia rettgeri Shigella spp Salmonella spp
The MicroScan® Synergies plus" Gram-Negative with Cefuroxime is not intended for use with:
Enterobacter sop Klebsiella pneumoniae
MicroScan® rapID/S plus™ Gram-Negative MIC/Combo Panels are designed for use in determining quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of rapidly growing aerobic and facultative anaerobic gram-negative bacilli. The MicroScan® rapID/S plus™ Gram-Negative MIC/Combo Panels are read on the WalkAway® System or equivalent (upgraded WalkAway® 40 or WalkAway® 96 instruments).
The antimicrobial susceptibility tests are miniaturizations of the broth dilution susceptibility test that have been diluted in Mueller-Hinton Broth to concentrations bridging the range of clinical interest and are presented in micro-titer wells in dried form. rapID/S plus™ panels are inoculated and rehydrated with a standardized suspension of the organism and incubated at 35°C in the WalkAway® SY System or equivalent for 4.5 - 18 hours. The minimum inhibitory concentration (MIC) for the test organism is determined by the lowest antimicrobial concentration showing inhibition of growth.
This document describes the acceptance criteria and study proving the device meets those criteria, based on the provided text.
1. Table of Acceptance Criteria and Reported Device Performance
| Performance Metric | Acceptance Criteria (FDA DRAFT Guidance, March 8, 2000) | Reported Device Performance (Cefuroxime) |
|---|---|---|
| Essential Agreement (Overall) | Not explicitly stated in the document, but contextually implied to be high for substantial equivalence | 97% (with parenteral and oral breakpoints) |
| Reproducibility and Precision | Acceptable | Acceptable |
| Quality Control Testing | Acceptable | Acceptable |
2. Sample Size and Data Provenance
- Test Set Sample Size: The document mentions "external evaluation was conducted with fresh and stock Efficacy isolates and stock Challenge strains." However, specific numerical sample sizes for these isolates and strains are not provided.
- Data Provenance: The evaluation involved "fresh and stock Efficacy isolates" and "stock Challenge strains." This suggests a mix of retrospective (stock strains) and potentially prospective (fresh isolates) data. The origin of these isolates and strains (e.g., country of origin) is not specified.
3. Number of Experts and Qualifications for Ground Truth
The document states that "Challenge strains were compared to Expected Results determined prior to the evaluation." This implies that experts were involved in establishing the "Expected Results" for the Challenge strains, which served as part of the ground truth. However:
- The number of experts is not specified.
- The qualifications of these experts are not specified.
4. Adjudication Method for the Test Set
The document does not describe an explicit adjudication method for the test set. The comparison was primarily against an "NCCLS frozen Reference Panel" for efficacy isolates and "Expected Results" for challenge strains. This suggests a direct comparison method rather than an independent adjudication process involving multiple readers resolving discrepancies.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
A Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not mentioned in the provided text. The study focuses on comparing the device's performance to a reference standard, not on human reader performance with and without AI assistance.
6. Standalone (Algorithm Only) Performance Study
Yes, a standalone performance study was conducted. The "external evaluation" and comparison to the "NCCLS frozen Reference Panel" and "Expected Results" for challenge strains represents the performance of the MicroScan® rapID/S plus™ Gram-Negative MIC/Combo Panel with Cefuroxime itself (the algorithm/device).
7. Type of Ground Truth Used
The ground truth used for the test set consists of two main components:
- Reference Standard (NCCLS frozen Reference Panel): For efficacy isolates, the device's performance was compared against an NCCLS (National Committee for Clinical Laboratory Standards) frozen Reference Panel. This is a recognized standard in antimicrobial susceptibility testing.
- Expert-Determined Expected Results: For challenge strains, the ground truth was "Expected Results determined prior to the evaluation." This implies a form of expert consensus or established reference values for these specific strains.
8. Sample Size for the Training Set
The document does not provide any information regarding a distinct training set sample size or how the device was trained. The focus is solely on the external evaluation (testing) phase.
9. How Ground Truth for Training Set Was Established
Since no training set is mentioned, information on how its ground truth was established is not provided.
§ 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.”