(185 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 addition of the antimicrobial agent cefepime at concentrations of 0.5-64 ug/mL to gram-negative ID/AST or AST only Phoenix panels. Cefepime 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.
This document describes the validation study for the BD Phoenix™ Automated Microbiology System for the antimicrobial agent Cefepime (0.5-64 ug/mL) for Gram-Negative ID/AST or AST only Phoenix panels.
1. A table of acceptance criteria and the reported device performance
The provided text does not contain a specific table detailing acceptance criteria for the Cefepime agent. However, the FDA's decision letter indicates that the device was deemed "substantially equivalent" to predicate devices, implying that its performance met the necessary thresholds for an antimicrobial susceptibility test system. Substantial equivalence generally means that the device is as safe and effective as a legally marketed device.
For antimicrobial susceptibility testing, typical acceptance criteria would involve comparing the device's Minimum Inhibitory Concentration (MIC) results to a reference method (e.g., broth microdilution). The performance would then be evaluated based on:
- Essential Agreement (EA): The percentage of MIC values that are within a specified range (e.g., +/- one 2-fold dilution) of the reference method.
- Categorical Agreement (CA): The percentage of isolates where the device's interpretive category (Susceptible, Intermediate, Resistant) matches the reference method's category.
- Major Errors (ME): Cases where the device reports susceptible when the reference method reports resistant.
- Very Major Errors (VME): Cases where the device reports resistant when the reference method reports susceptible.
The FDA's statement of substantial equivalence confirms that the device's performance for Cefepime fell within acceptable limits for these metrics, allowing it to be marketed. Without the full study report, specific percentages for EA, CA, ME, and VME cannot be provided from this text.
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
The provided text does not explicitly state the sample size used for the test set or the data provenance (country of origin, retrospective/prospective nature). This information would typically be found in the detailed study report submitted to the FDA, which is not included in the provided excerpt.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
The provided text does not specify the number or qualifications of experts used to establish the ground truth for the test set. For antimicrobial susceptibility testing, the "ground truth" (reference method) is usually a standardized laboratory method, often a broth microdilution or agar dilution method, which is performed by trained microbiologists following established protocols (e.g., CLSI guidelines).
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
The provided text does not describe any adjudication method. In the context of antimicrobial susceptibility testing, adjudication methods like N+1 are less typical unless there's an ambiguity in the reference method itself or a discrepancy that needs further investigation. The "ground truth" is generally considered to be the result of a meticulously performed, standardized reference method.
5. 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
The BD Phoenix™ Automated Microbiology System is an automated system for antimicrobial susceptibility testing. It is not an AI-assisted device for human reader interpretation in the sense of diagnostic imaging. Therefore, an MRMC comparative effectiveness study involving human readers improving with or without AI assistance is not applicable to this device. The system automates the process of determining MIC and interpretive categories.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Yes, the regulatory information indicates that this is a standalone (algorithm only) performance study. The BD Phoenix system is described as an "Automated Microbiology System" that performs "rapid identification and in vitro antimicrobial susceptibility testing of isolates from pure culture." This means the system, including its software and panels, determines the susceptibility results independently, without direct human cognitive input for interpreting the test results themselves. Human operators perform initial steps like inoculum preparation and loading, but the determination of susceptibility is by the automated system.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
For antimicrobial susceptibility testing, the "ground truth" is established by a reference method, typically a standardized broth microdilution or agar dilution method as per guidelines from organizations like the Clinical and Laboratory Standards Institute (CLSI). This method involves preparing serial dilutions of the antimicrobial agent and inoculating them with a standardized bacterial suspension to determine the lowest concentration that inhibits visible bacterial growth (MIC). The FDA approval would have been based on comparison of the Phoenix system's results to such a reference method.
8. The sample size for the training set
The provided text does not state the sample size for the training set. This information would be present in the more detailed submission document to the FDA.
9. How the ground truth for the training set was established
The provided text does not specify how the ground truth for the training set was established. Similar to the test set, it would typically involve using a standardized reference method (e.g., broth microdilution) to determine the true MIC and interpretive category for each isolate used in the training set.
§ 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.”