(51 days)
The BD Phoenix™ Automated Microbiology System is intended for the rapid identification and in vitro antimicrobial susceptibility testing of isolates from pure culture of most aerobic and facultative anaerobic Gram-negative and Gram-positive bacteria of human origin.
The BD Phoenix™ Automated Microbiology System is intended for in vitro quantitative determination of antimicrobial susceptibility by minimal inhibitory concentration (MC) of most Gram-negative aerobic and facultative anaerobic bacteria isolates from pure culture for Enterobacteriaceae and Non-Enterobacteriaceae and most Gram-positive bacteria isolates from pure culture belonging to the genera Staphylococcus and Enterococcus.
This premarket notification is for the addition of the antimicrobial agent ampicillin at concentrations of 0.0625 - 32 µg/mL to Gram Positive ID/AST or AST only Phoenix pancls. Ampicillin has been shown to be active in vitro against most strains of microorganisms listed below, as described in the FDA-approved package insert for this antimicrobial agent.
Active In Vitro and in Clinical Infections Against:
Enterococcus spp.
The BD Phocnix Autornated Microbiology System (Phoenix System) is an automated system for the TIK DD Thounk Halonated Microbial susceptibility testing (AST) of clinically relevant bacterial isolates. The system includes the following components:
- BD Phocnix instrument and software. .
- BD Phoenix panels containing biochemicals for organism ID testing and antimicrobial agents g or AST determinations.
- BD Phoenix ID Broth used for performing ID tests and preparing AST Broth inoculum. .
- BD Phoenix AST Broth used for performing AST tests only. ♥
- BD Phocnix AST Indicator solution added to the AST Broth to aid in bacterial growth . determination.
The Phoenix panel is a scaled and sclf-inoculating molded polystyrene tray with 136 micro-wells The I noomis punct is a ve. Organisms for susceptibility testing must be a purc culture and contaning dreatified as a Gram-negative or Gram-positive isolate. For cach isolate, an inoculation couivalent to a 0.5 McFarland standard is prepared in Phoenix ID broth.
The Phocnix AST mcthod is a broth based microdilution test. The Phoenix System utilizes a redox indicator for the detection of organism growth in the presence of an antimicrobial agent. murcator for the decours on the indicator as well as bacterial turbidity are used in the determination Measurements of backers and configuration contains several antimicrobial agents with a wide range of two-fold doubling dilution concentrations.
The instrument houses :he panels where they are continuously incubated at a nominal temperature of 35°C. The instrument takes readings of the panels every 20 minutes. The readings are interpreted to give an identification of the isolate, minimum inhibitory concentration (MIC) values and category interpretations, S, I, R or N (susceptible, intermediate, resistant or not susceptible).
Here's a breakdown of the acceptance criteria and study details based on the provided text for the BD Phoenix™ Automated Microbiology System - Ampicillin:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Typically FDA Guidance) | Reported Device Performance (BD Phoenix System - Ampicillin) |
|---|---|
| Essential Agreement (EA) | Not explicitly stated as a single percentage acceptance criterion in the provided text. |
| Category Agreement (CA) | Not explicitly stated as a single percentage acceptance criterion in the provided text. |
| Intra-site Reproducibility | > 90% |
| Inter-site Reproducibility | > 95% |
Note on "Acceptance Criteria" vs. "Reported Performance": The document doesn't explicitly state the numerical acceptance thresholds for EA and CA (e.g., "EA must be >90%"). Instead, it states that performance was assessed by calculating EA and CA and then presents the results. However, the FDA's "Guidance on Review Criteria for Assessment of Antimicrobial Susceptibility Devices" (March 8, 2000), which is referenced, would contain these criteria. For the purpose of this response, I've listed the reported performance as it aligns with typical expectations for substantial equivalence.
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Sample Size: The clinical study tested "clinical, stock and challenge isolates." For Ampicillin specifically, the table indicates
EA (n) = 475andCA (n) = 475. This suggests a test set of 475 isolates for the performance evaluation of Ampicillin. - Data Provenance: The study involved "multiple geographically diverse sites across the CITED STATES." This indicates it was a prospective study gathering data from various locations.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not specify the number of experts or their qualifications for establishing the ground truth.
4. Adjudication Method for the Test Set
The document does not specify any adjudication method for the test set. The ground truth for clinical isolates was established by comparing to the "NCCLS reference broth microdilution method." For challenge isolates, results were compared to "expected results," implying a predetermined outcome.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study Was Done, If So, What Was the Effect Size of How Much Human Readers Improve with AI vs Without AI Assistance
- No, an MRMC comparative effectiveness study was not done.
- This device is an automated microbiology system that performs antimicrobial susceptibility testing (AST) mechanically. It's not an AI-assisted diagnostic imaging or interpretation device that would involve human "readers" in the typical sense of an MRMC study. The comparison is between the automated system and a reference microbiology method, not between human performance and human performance with AI assistance.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
- Yes, a standalone study was done. The entire "Clinical Studies" section describes the performance of the "Phoenix System results" compared to the reference method (NCCLS broth microdilution). This is a direct measure of the device's (algorithm's) performance without human intervention in the interpretation of the results. The system takes readings and interprets them automatically.
7. The Type of Ground Truth Used
- For clinical isolates: The ground truth was established using the NCCLS reference broth microdilution method. This is a well-established and accepted laboratory reference method for antimicrobial susceptibility testing.
- For challenge isolates: The ground truth was based on "expected results," implying predetermined or known susceptibility profiles for these specific strains.
8. The Sample Size for the Training Set
The document does not specify the sample size for a training set. The descriptions focus on the performance evaluation (test set). It's possible that the "stock" isolates mentioned were used for development/training, but this is not explicitly stated, nor is a number provided. This type of device (a microdilution system) generally relies on fixed physicochemical principles and established interpretive criteria rather than a machine learning model that requires a distinct "training set" in the modern AI sense.
9. How the Ground Truth for the Training Set Was Established
Since the document does not specify a training set in the AI/ML sense, it also does not describe how ground truth for such a set was established. The development of the system itself would have involved extensive R&D and validation against known standards, much like the reference methods themselves.
§ 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.”