Search Results

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 and facultative anaerobic bacteria isolates from pure culture for Enterobacteriaceae and most Gram-positive bacteria isolates from pure culture belonging to the genera Staphylococcus, and Streptococcus.

Meropenem-vaborbactam 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 Enterobacter cloacae species complex Escherichia coli Klebsiella pneumoniae

Active In Vitro but clinical significance is unknown Citrobacter freundii Citrobacter koseri Enterobacter aerogenes Klebsiella oxytoca Morganella morganii Proteus mirabilis Providencia spp. Serratia marcescens

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. Inoculum for use with the Phoenix system may be prepared either manually or may be automated using the BD Phoenix™ AP System.

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° ± 1°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).

1. Acceptance Criteria and Reported Device Performance

2. Sample Size Used for the Test Set and Data Provenance

• Test Set Sample Size for Clinical and Challenge Isolates: 1141 isolates.
• Data Provenance: The study used a combination of clinical, stock, and challenge isolates. These were tested across multiple geographically diverse sites across the United States. This indicates a prospective and multi-site approach for clinical data collection, supplemented with controlled "stock" and "challenge" isolates. Specific details on the breakdown of clinical vs. stock/challenge isolates are not provided, nor is the exact number of contributing sites.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

The document does not specify the number of experts used or their qualifications for establishing ground truth. However, the ground truth for clinical isolates was established by the CLSI reference broth microdilution method. This is a standardized laboratory method, and its execution would typically involve trained laboratory personnel rather than a subjective expert consensus in the way a radiologist reads an image. For "expected results" for challenge isolates, this typically refers to pre-determined, known susceptibility profiles.

4. Adjudication Method for the Test Set

The document does not describe an adjudication method in the traditional sense of multiple expert readers. The comparison is made against the CLSI reference broth microdilution method for clinical isolates and "expected results" for challenge isolates. These are objective, laboratory-based methods, removing the need for a subjective adjudication process by human experts.

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

No, a Multi Reader Multi Case (MRMC) comparative effectiveness study was not done. The device is an automated microbiology system that performs antimicrobial susceptibility testing (AST) and does not involve human readers in the interpretation of results in the way an AI for image analysis would. Therefore, the concept of human readers improving with or without AI assistance is not applicable to this device.

6. 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 providing quantitative determination of antimicrobial susceptibility. Its performance (Essential Agreement and Category Agreement) was directly compared to the CLSI reference broth microdilution method, which represents its standalone performance without human interpretation of the primary data generated by the system.

7. The Type of Ground Truth Used

• Clinical Isolates: The ground truth was established using the CLSI reference broth microdilution method (AST panels prepared according to CLSI M7). This is a gold standard laboratory method for antimicrobial susceptibility testing.
• Challenge Isolates: The ground truth was based on "expected results," implying pre-defined or known susceptibility profiles for these controlled isolates.

8. The Sample Size for the Training Set

The document does not explicitly mention a "training set" or its sample size. This type of device is an automated laboratory instrument, and its performance is typically evaluated against reference methods rather than through a machine learning training paradigm with separate training and test sets as seen in AI imaging devices. The "training" in this context would likely refer to the initial development and calibration of the system by the manufacturer using internal data, which is not detailed in this regulatory summary.

9. How the Ground Truth for the Training Set Was Established

Since a "training set" is not explicitly discussed as per the typical AI/ML development cycle, there is no information on how its ground truth was established within this document. The focus of the 510(k) submission is on the comparison of the device's performance against established reference methods (CLSI broth microdilution) for the purpose of demonstrating substantial equivalence.

Ask a specific question about this device