(62 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 antimicrobial agent ticarcillin at concentrations of 1-128 ug/mL to Gram-negative ID/AST or AST only Phoenix panels. Ticarcillin 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 Against:
Pseudomonas aeruginosa Escherichia coli Proteus mirabilis Morganella morganii
Providencia rettgeri Enterobacter species Salmonella species
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).
The provided 510(k) summary describes the BD Phoenix™ Automated Microbiology System for susceptibility testing of Ticarcillin against Gram-negative isolates. Here's a breakdown of the acceptance criteria and study details:
1. Table of Acceptance Criteria and Reported Device Performance:
| Performance Metric | Acceptance Criteria (FDA Guidance*) | Reported Device Performance (%) |
|---|---|---|
| Essential Agreement (EA) | Not explicitly stated as a numerical threshold in the document, but good performance is expected. | 94.0 |
| Category Agreement (CA) | Not explicitly stated as a numerical threshold in the document, but good performance is expected. | 97.1 |
| Intra-site Reproducibility | Greater than 90% | Greater than 90% |
| Inter-site Reproducibility | Greater than 95% | Greater than 95% |
*The document refers to the FDA Draft guidance document, "Guidance on Review Criteria for Assessment of Antimicrobial Susceptibility Devices", March 8, 2000, for acceptance criteria. Specific numerical thresholds for EA and CA for this type of device are typically outlined in such guidance documents, but they are not explicitly presented as pass/fail criteria in the provided text. The provided EA and CA percentages represent the device's performance.
2. Sample Size Used for the Test Set and Data Provenance:
- Sample Size for Test Set:
- Clinical isolates (for EA/CA): 2294 (This is the 'n' value reported for EA and CA in Table 1).
- Reproducibility study: A "panel of Gram-negative isolates" was tested, but a specific number is not provided.
- Data Provenance: The isolates were tested "across multiple geographically diverse sites across the United States." The data is prospective, as it involves testing isolates using the Phoenix system and comparing them to a reference method.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications:
The document does not explicitly state the number of experts or their qualifications for establishing ground truth. However, the ground truth for clinical isolates was established by the NCCLS reference broth microdilution method (AST panels prepared according to NCCLS M7). This method itself is a standardized and recognized "expert" method. For challenge set isolates, the Phoenix System results were compared to "expected results," which implies pre-defined or externally verified ground truth, likely from expert consensus or established references.
4. Adjudication Method for the Test Set:
The document does not describe an explicit adjudication method (like 2+1 or 3+1). The comparison was made against a single reference method (NCCLS broth microdilution) for clinical isolates, and against "expected results" for challenge isolates. Discrepancies would likely be investigated, but a multi-expert adjudication process isn't detailed.
5. If a Multi-reader Multi-case (MRMC) Comparative Effectiveness Study was done:
No, an MRMC comparative effectiveness study involving human readers is not described. This device is an automated system for antimicrobial susceptibility testing, not an imaging or diagnostic device that typically involves human interpretation. The study focuses on the device's performance compared to a reference standard, not on human reader improvement with AI assistance.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Study was done:
Yes, this was a standalone study. The BD Phoenix™ Automated Microbiology System is an automated system. Its performance (MIC values and categorical interpretation) was evaluated directly against the reference method without human interpretation being the primary variable. Human input is involved in preparing the inoculum and loading the panels, but the interpretive algorithm is standalone from that point.
7. The Type of Ground Truth Used:
- Clinical Isolates: The ground truth was established using the NCCLS reference broth microdilution method (AST panels prepared according to NCCLS M7). This is a well-established and recognized laboratory standard for antimicrobial susceptibility testing, often considered the gold standard.
- Challenge Isolates: The ground truth for these isolates was "expected results," implying pre-determined or reference values.
8. The Sample Size for the Training Set:
The document does not explicitly state a sample size for a training set. The Phoenix system's underlying algorithms and models would have been developed and trained using a large dataset, but this 510(k) summary focuses on the validation study for this specific antimicrobial agent (Ticarcillin) and its performance against the reference method. It's common for 510(k) submissions to not detail the training set unless modifications to the core algorithm are being made that necessitate re-training or re-validation that is different from previous submissions.
9. How the Ground Truth for the Training Set Was Established:
Since a training set is not explicitly mentioned or detailed in this document, the method for establishing its ground truth is also not described. For the type of device, a training set would likely involve isolates with known antimicrobial susceptibility results determined by reference methods (like NCCLS broth microdilution) to train the automated system's algorithms for growth detection and MIC determination.
§ 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.”