(110 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-Enteriaceae and most Gram-positive bacteria isolates from pure culture belonging to the genera Staphylococcus, Enterococcus, and Streptococcus.
This premarket notification is for the addition of the antimicrobial agent Minocycline at concentrations of 1-32 µg/mL to Gram-negative ID/AST or AST only Phoenix panels. Minocycline 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:
Acinetobacter species
Enterobacter aerogenes
Escherichia coli
Klebsiella species
Shigella 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. Phoenix panels are inoculated with a specified organism density and placed into the instrument.
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 twofold 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 provided text, outlining the acceptance criteria and study details for the BD Phoenix™ Automated Microbiology System with Minocycline:
Acceptance Criteria and Device Performance
The core performance metrics for this device are Essential Agreement (EA) and Category Agreement (CA) when compared to a CLSI reference broth microdilution method.
| Acceptance Criteria (Not explicitly stated as percentage, but implied by typical FDA guidance) | Reported Device Performance (Table 1 - Minocycline for gram-negative organisms) |
|---|---|
| Essential Agreement (EA): Agree exactly or within ± one two-fold dilution to the reference result. (Typically >90% for new AST devices) | The provided Table 1 is incomplete and corrupted, making it impossible to extract the exact Essential Agreement percentage for Minocycline. |
| Category Agreement (CA): Agree with the reference method with respect to FDA categorical interpretive criteria (susceptible, intermediate, and resistant). (Typically >90% for new AST devices) | The provided Table 1 is incomplete and corrupted, making it impossible to extract the exact Category Agreement percentage for Minocycline. |
Note: The provided "Table 1" is severely corrupted and unreadable. Therefore, the specific reported device performance percentages for Essential Agreement and Category Agreement for Minocycline cannot be extracted from this document. The document states, "Table 1 summarizes the performance for the isolates tested in this study." and implies this table would contain the numerical results.
Study Details
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Sample Size Used for the Test Set and Data Provenance:
- Test Set Sample Size: Not explicitly stated as a single number. The study tested "Clinical, stock and challenge isolates."
- Data Provenance: "multiple geographically diverse sites across the United States." The study included both "Clinical, stock and challenge isolates." Clinical isolates were compared to the CLSI reference method, and challenge isolates were compared to expected results.
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Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of those Experts:
- Not specified. The ground truth method is the CLSI reference broth microdilution method, which is a standardized laboratory procedure, not typically established by individual "experts" in the same way as, for example, image interpretation. For challenge isolates, "expected results" were used, but the method of establishing these expected results or by whom is not detailed.
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Adjudication Method for the Test Set:
- Not applicable in the context of this type of study. The comparison is between the automated system's results and the standardized CLSI reference method. Discrepancies would be analyzed, but a multiple-expert adjudication process isn't described for determining the "true" MIC or category.
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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 imaging tool for human readers. It automates a laboratory process.
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If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Yes, this was a standalone performance study. The BD Phoenix™ system is an "Automated Microbiology System" that performs ID and AST. Its performance was compared directly to a "CLSI reference broth microdilution method," indicating an algorithm-only evaluation against a gold standard.
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The type of ground truth used:
- CLSI reference broth microdilution method for clinical isolates.
- Expected results for challenge isolates. This implies a predetermined "true" susceptibility profile for the challenge strains, likely established through extensive prior testing.
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The sample size for the training set:
- Not applicable/mentioned. As this is an older device (510(k) in 2007) for an automated microbiology system, the term "training set" in the context of machine learning isn't directly relevant to its development and validation as described. The system's rules for interpreting growth and MICs are likely based on established microbiological principles, not trained on a distinct "training set" of data in the modern sense of AI algorithms.
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How the ground truth for the training set was established:
- Not applicable. The primary "ground truth" reference method for validation is the CLSI reference broth microdilution, which serves as the comparative standard, not a "training set" ground truth. The system's internal logic and algorithms would have been developed based on scientific understanding of microbial growth and susceptibility, rather than a data-driven training process with externally established ground truth labels.
§ 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.”