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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 ticarcillin/clavulanate at concentrations of 1/2 - 128/2 µg/mL to gram-negative ID/AST or AST only Phoenix panels. Ticarcillin/clavulanate 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.

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 isolation 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, or R (sensitive, intermediate, or resistant).

The acceptance criteria and study details for the BD Phoenix™ Automated Microbiology System's performance with ticarcillin/clavulanate are described below, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance:

2. Sample size used for the test set and the data provenance:

• Sample Size: Not explicitly stated as an overall number. The study utilized "Clinical, stock and challenge isolates."
• Data Provenance: The isolates were tested "across multiple geographically diverse sites across the United States." The study included both "Clinical isolates" and "Challenge set isolates." This indicates a mix of retrospective (clinical isolates from past patient samples) and potentially prospective (challenge isolates specifically designed for testing) data, originating from the United States.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

• Number of Experts: Not specified.
• Qualifications of Experts: Not specified. The ground truth was established by comparison to the "NCCLS reference broth microdilution method" and "expected results" for challenge isolates. This suggests expert consensus on the interpretation of reference method results, but the experts themselves are not detailed.

4. Adjudication method for the test set:

• Adjudication Method: Not explicitly described in terms of a specific "X+Y" methodology. The Phoenix System results were "compared to the expected results" (for challenge isolates) and "compared to the results obtained from the NCCLS reference broth microdilution method" (for clinical isolates). This implies the NCCLS reference method and pre-defined expected results served as the definitive ground truth against which the device's performance was measured.

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:

• MRMC Study: No, this does not appear to be an MRMC comparative effectiveness study involving human readers and AI assistance. The device is an automated system for antimicrobial susceptibility testing; it does not involve human readers interpreting images or data with or without AI assistance in the context of a typical MRMC study.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:

• Standalone Performance: Yes, this entire study is focused on the standalone performance of the BD Phoenix™ Automated Microbiology System (the "algorithm only") without an explicit "human-in-the-loop" component for interpretation. The system automates the preparation, incubation, reading, and interpretation of results.

7. The type of ground truth used:

• Type of Ground Truth: The ground truth for clinical isolates was the NCCLS reference broth microdilution method. For challenge isolates, the ground truth was expected results.

8. The sample size for the training set:

• Sample Size: The document does not provide details on a separate "training set" or its size. The described studies focus on testing the performance of the system against a reference method. For antimicrobial susceptibility devices, the "training" (or development) of the device's interpretive algorithms would typically occur prior to these validation studies, and the specifics of that development dataset are not included in this 510(k) summary.

9. How the ground truth for the training set was established:

• Ground Truth for Training Set: Not specified, as details about a distinct training set are not provided in this document. The device's internal algorithms would have been developed using some form of reference data, likely the NCCLS reference method for AST, but the specifics are not elaborated here.

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