(56 days)
The BD Phoenix™ Automated Microbiology System is intended for in vitro quantitative determination of susceptibility by minimal inhibitory concentration (MC) of most Gram-negative aerobic and facultative anaerobic bacteria isolates from pure culture for Enterobacteriaceae and Non-Enterobacteriaceae land 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 penicillin at concentrations of 0.0625-32 µg/mL to Gram Positive ID/AST or AST only Phoenix panels. Penicillin has been shown to be active in viro 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:
Active In Vitro Against: Staphylococcus spp. (except penicillinase-producing strains)
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 . 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 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, R or N (susceptible, intermediate, resistant or not susceptible).
Here's an analysis of the provided text, outlining the acceptance criteria and study details for the BD Phoenix™ Automated Microbiology System for Penicillin.
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria Type | Acceptance Criteria | Reported Device Performance (Penicillin) |
|---|---|---|
| Site Reproducibility | ||
| Intra-site Reproducibility | > 90% | > 90% (for Gram-positive isolates) |
| Inter-site Reproducibility | > 95% | > 95% (for Gram-positive isolates) |
| Clinical Performance | ||
| Essential Agreement (EA) | Not explicitly stated as a numerical threshold, but assessed against reference method | "substantially equivalent performance" to NCCLS reference method |
| Category Agreement (CA) | Not explicitly stated as a numerical threshold, but assessed against reference method | "substantially equivalent performance" to NCCLS reference method |
Note: The document states "The data collected from the substantial equivalence studies demonstrate that testing on the BD Phoenix™ Automated Microbiology System with this antimicrobial agent is substantially equivalent as outlined in the FDA draft guidance document, 'Guidance on Review Criteria for Assessment of Antimicrobial Susceptibility Devices', March 8, 2000." While specific numerical thresholds for EA and CA for this particular submission are not explicitly provided in the excerpt, the FDA guidance document typically outlines these. The provided text indicates the device met these unstated criteria.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: The document does not provide a specific total number of isolates for the clinical studies. It mentions "a panel of Gram-positive isolates" for reproducibility and "Clinical, stock and challenge isolates" for the clinical studies.
- Data Provenance:
- Country of Origin: United States ("across multiple geographically diverse sites across the United States").
- Retrospective/Prospective: Not explicitly stated, but the mention of "clinical isolates," "stock isolates," and "challenge isolates" suggests a mix, with clinical isolates likely being prospective or recently collected, and stock/challenge isolates being pre-existing.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The document does not mention the use of experts or their qualifications for establishing ground truth. The ground truth was established by a reference method.
4. Adjudication Method for the Test Set
Not applicable. The ground truth was established by comparison to a reference method, not by expert consensus requiring adjudication.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, and its effect size.
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. The study compares the automated system's performance to a reference method, not human readers with and without AI assistance.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done.
Yes, this was a standalone study. The BD Phoenix™ Automated Microbiology System's performance was evaluated independently against a reference method. It's an automated system performing "algorithm only" in this context.
7. The type of ground truth used.
The type of ground truth used was a reference method, specifically the NCCLS reference broth microdilution method (AST panels prepared according to NCCLS M7). For challenge set isolates, the ground truth was "expected results."
8. The sample size for the training set.
The document does not provide information on the sample size for a training set. This is a 510(k) submission for a device, not a machine learning algorithm that typically undergoes a separate training phase with distinct training data. The "training" of the system would have occurred during its initial development and validation, prior to this specific submission for a new antimicrobial agent.
9. How the ground truth for the training set was established.
Not applicable, as a separate "training set" with ground truth establishment for a machine learning algorithm is not described in this document. The system's underlying methodology for determining MIC values and categorical interpretations would have been established and refined during its development, likely using similar reference methods.
§ 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.”