(43 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.
This premarket notification is for ceftazidime at concentrations of 0.5-64 µg/mL to Gram-negative ID/AST or AST only Phoenix panels with the removal of the limitations for Citrobacter freundii and Stenotrophomonas maltophilia. Ceftazidime 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.
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 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 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. Phoenix panels are inoculated with a specified organism density and placed in the instrument.
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).
The provided text describes the acceptance criteria and the study that proves the performance of the BD Phoenix™ Automated Microbiology System for the antimicrobial agent Ceftazidime (0.5-64 µg/mL) against Gram-negative organisms.
Here's a breakdown of the requested information:
1. Table of Acceptance Criteria and Reported Device Performance:
| Acceptance Criteria | Reported Device Performance (Ceftazidime) |
|---|---|
| Essential Agreement (EA) | 96.6% (n=2388) |
| Category Agreement (CA) | 94.7% (n=2388) |
Notes:
- Essential Agreement (EA): Occurs when the BD Phoenix™ Automated Microbiology System agrees exactly or within ± one two-fold dilution to the reference result.
- Category Agreement (CA): Occurs when the BD Phoenix™ Automated Microbiology System agrees with the reference method with respect to the FDA categorical interpretive criteria (susceptible, intermediate, and resistant).
2. Sample Size Used for the Test Set and Data Provenance:
- Sample Size for Test Set: 2388 isolates (for both EA and CA calculations).
- Data Provenance: Clinical, stock, and challenge isolates were tested across multiple geographically diverse sites across the United States. This indicates a prospective study design with data collected from various real-world clinical settings, supplemented by controlled stock and challenge isolates.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
- The document does not explicitly state the number of experts or their qualifications used to establish the ground truth.
- However, the ground truth was established by comparison to the CLSI (formerly NCCLS) reference broth microdilution method. This implies that the ground truth was determined by trained laboratory personnel following established CLSI guidelines, rather than individual clinical experts.
4. Adjudication Method for the Test Set:
- The document does not explicitly mention an adjudication method (like 2+1 or 3+1).
- The comparison was directly between the Phoenix System results and the CLSI reference method. For challenge sets, results were compared to "expected results."
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
- No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done.
- This study focuses on the device's performance compared to a reference method, not on how human readers' performance improves with or without AI assistance. The BD Phoenix system is an automated AST system without direct human interpretation in the susceptibility determination process.
6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study:
- Yes, this was a standalone (algorithm only) performance study.
- The BD Phoenix™ Automated Microbiology System is an automated device designed to determine antimicrobial susceptibility without human subjective interpretation of results, beyond initial setup and reading the instrument's output. The performance metrics (EA and CA) directly reflect the device's accuracy against a gold standard.
7. Type of Ground Truth Used:
- The ground truth used was the CLSI (formerly NCCLS) reference broth microdilution method. This is a recognized laboratory standard for antimicrobial susceptibility testing. For challenge isolates, "expected results" were used, which would typically be based on established phenotypic or genotypic characteristics.
8. Sample Size for the Training Set:
- The document does not provide information regarding a specific "training set" or its sample size. This type of regulatory submission typically focuses on validation data against a gold standard rather than the developmental or training process of the device which probably uses proprietary data or earlier version's training data.
9. How the Ground Truth for the Training Set Was Established:
- As the document does not mention a specific training set size, it also does not explain how the ground truth for any training set was 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.”