(46 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, Enterococcus and Streptococcus.
This premarket notification is for ticarcillin/clavulanate at concentrations of 1/2 - 128/2 µg/mL to Gramnegative ID/AST or AST only Phoenix panels with additional organisms and the removal of the limitations for Pseudomonas species and Stenotrophomonas maltophilia. Ticarcillin/clavulanate has been shown to be active in vitro against most strains of microorganisms listed below, as described in the FDAapproved 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).
Here's a summary of the acceptance criteria and study details from the provided document:
Acceptance Criteria and Device Performance
The document doesn't explicitly state quantitative acceptance criteria in a table format with thresholds. Instead, it refers to "Essential Agreement (EA)" and "Category Agreement (CA)" as the metrics for assessing performance against a reference method. The acceptable range for these agreements is implied to be high enough to demonstrate substantial equivalence to the CLSI reference broth microdilution method, as defined by the FDA guidance document "Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA", February 5, 2003.
| Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|---|
| Essential Agreement (EA) | Sufficiently high to demonstrate substantial equivalence to CLSI reference method. | Not explicitly stated with a specific percentage in the provided text. The document states "The performance of the Phoenix System was assessed by calculating Essential Agreement (EA) and Category Agreement (CA) to expected/reference results for all isolates tested." and summarizes "Performance of BD Phoenix System for Gram-Negative Organisms by Drug" in Table 1, but the values are cut off or not clearly presented. |
| Category Agreement (CA) | Sufficiently high to demonstrate substantial equivalence to CLSI reference method. | Not explicitly stated with a specific percentage in the provided text, for similar reasons as EA (cut-off/unclear in Table 1). |
Note: The provided "Table 1: Performance of BD Phoenix System for Gram-Negative Organisms by Drug" is incomplete and unreadable in the input, making it impossible to report the precise device performance numbers claimed in the study.
Study Details:
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Sample size used for the test set and the data provenance:
- Test Set Sample Size: Not explicitly stated as a single number. The study utilized "Clinical, stock and challenge isolates."
- Data Provenance: Multiple geographically diverse sites across the United States. The study included both "Clinical, stock and challenge isolates." The clinical isolates likely represent retrospective sampling from these sites. Challenge isolates are typically laboratory-prepared to test specific conditions.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- This information is not provided in the document. The ground truth for clinical isolates was established by the "CLSI reference broth microdilution method," which is a standardized laboratory procedure, not typically through expert consensus on individual cases. For challenge isolates, ground truth was "expected results," implying predefined outcomes based on strain characteristics.
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Adjudication method for the test set:
- Not applicable in the sense of expert adjudication of individual cases. The comparison was against the CLSI reference broth microdilution method for clinical isolates and "expected results" for challenge isolates. Performance metrics (EA and CA) were calculated based on direct comparison to these reference standards.
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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, a multi-reader, multi-case comparative effectiveness study with human readers was not performed or described. This device is an automated system for antimicrobial susceptibility testing, not an AI-assisted diagnostic device for human interpretation.
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If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Yes, a standalone performance study was done. The BD Phoenix Automated Microbiology System is an automated system that provides results (MIC values and category interpretations S, I, or R) without human interpretation in the loop. Its performance was compared against the CLSI reference method.
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The type of ground truth used:
- For Clinical Isolates: The CLSI reference broth microdilution method served as the ground truth. This is a consensus-based, standardized laboratory method.
- For Challenge Isolates: "Expected results" served as the ground truth, implying predefined results based on the known characteristics of the challenge strains.
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The sample size for the training set:
- The document does not provide specific details on a training set sample size. The description pertains to the evaluation of the device as a whole, including its established methodology, rather than a machine learning model requiring a separate training phase. The "study" described is a validation study demonstrating concordance with a reference method.
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How the ground truth for the training set was established:
- As no separate training set is explicitly mentioned or described for a machine learning model, this information is not applicable/not provided. The device's underlying technology uses a "broth based microdilution test" with "redox indicator for the detection of organism growth" and "bacterial turbidity" measurements, which are established principles of microbiology, not learned from a training dataset in the AI sense.
§ 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.”