(31 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 (MIC) 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 amoxicillin/clavulanate at concentrations of 0.5/0.25-32/16 ug/mL to Gram-negative ID/AST or AST only Phoenix panels. Amoxicillin/clavulanate 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:
Enterobacter species
Escherichia coli
Klebsiella species
Active In Vitro Against:
Proteus mirabilis
The BD Phoenix Automated Microbiology System (Phoenix System) is an automated system for the rapid identification (ID) and antimicrobial susceptibility testing (AST) of clinically relevant bacterial isolates. The system includes the following components:
- . BD Phoenix instrument and software.
- BD Phoenix panels containing biochemicals for organism ID testing and antimicrobial agents . for 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 Phoenix AST Indicator solution added to the AST Broth to aid in bacterial growth . determination.
The Phoenix panel is a sealed and self-inoculating molded polystyrene tray with 136 micro-wells containing dried reagents. Organisms for susceptibility testing must be a pure culture and preliminarily identified as a Gram-negative or Gram-positive isolate. For each isolate, an inoculation equivalent to a 0.5 McFarland standard is prepared in Phoenix ID Broth.
The Phoenix AST method 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. Measurements of changes to the indicator as well as bacterial turbidity are used in the determination of bacterial growth. Each AST panel configuration contains several antimicrobial agents with a wide range of two-fold doubling dilution concentrations.
The instrument houses the 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, or R (sensitive, intermediate, or resistant).
Here's an analysis of the acceptance criteria and study detailed in the provided text:
Acceptance Criteria and Device Performance
| Criteria | Reported Device Performance (BD Phoenix™ Automated Microbiology System - Amoxicillin/Clavulanate 0.5/0.25-32/16 µg/mL) |
|---|---|
| Site Reproducibility (Intra-site) | Greater than 90% for Gram-negative isolates |
| Site Reproducibility (Inter-site) | Greater than 95% for Gram-negative isolates |
| Essential Agreement (EA) | 96.5% (n=1919 isolates) |
| Category Agreement (CA) | 90.3% (n=1919 isolates) |
Study Details
2. Sample Size Used for the Test Set and Data Provenance:
- Sample Size: 1919 (total for both EA and CA calculations and across clinical, stock, and challenge isolates).
- Data Provenance:
- Country of Origin: United States (across multiple geographically diverse sites).
- Retrospective or Prospective: Not explicitly stated as retrospective or prospective, but clinical isolates were tested and compared to a reference method, suggesting this was part of a prospective evaluation for the device's performance.
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 ground truth.
- The ground truth for clinical isolates was established by the NCCLS reference broth microdilution method.
- The ground truth for challenge isolates was "expected results." The method for determining these "expected results" is not detailed, nor is the involvement of experts for these isolates.
4. Adjudication Method for the Test Set:
- The document does not explicitly state an adjudication method (such as 2+1 or 3+1).
- For clinical isolates, the BD Phoenix System results were compared to the NCCLS reference broth microdilution method as the gold standard. For challenge isolates, they were compared to "expected results." This suggests a direct comparison method rather than an adjudication process between multiple readers/interpretations of the Phoenix results themselves.
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 system for antimicrobial susceptibility testing, not an AI-assisted diagnostic tool for human readers. Therefore, the concept of human readers improving with AI assistance is not applicable here.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done:
- Yes, a standalone performance evaluation was done. The entire study is a standalone evaluation of the BD Phoenix Automated Microbiology System. The system itself determines the MIC values and category interpretations (S, I, or R) without human intervention in the interpretation process of the readings. Human involvement is primarily for preparing the inoculum and loading the panels, but the interpretive results are generated by the automated system.
7. The Type of Ground Truth Used:
- Clinical Isolates: NCCLS reference broth microdilution method (a standardized laboratory method).
- Challenge Isolates: "Expected results" (details not provided on how these "expected results" were determined).
8. The Sample Size for the Training Set:
- The document does not provide information regarding a separate training set. The study describes the validation of the system's performance, but it does not detail its development or any training data used to build its algorithms.
9. How the Ground Truth for the Training Set Was Established:
- Since a training set is not explicitly mentioned, no information is provided on how its ground truth would have been established.
§ 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.”