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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, Enterococcus, and Streptococcus.

This premarket notification is for cefuroxime with additional organism groups and the removal of the limitation for Klebsiella pneumoniae from the original premarket notification (K033362, April 13, 2004).

Cefuroxime 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:

Escherichia coli Enterobacter species Klebsiella species

Active In Vitro Against:

Citrobacter species Enterobacter species Escherichia coli Klebsiella species (including K. pneumoniae) Morganella morganii Proteus mirabilis Salmonella 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 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 into 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).

The provided document describes the acceptance criteria and study for the BD Phoenix™ Automated Microbiology System for Cefuroxime – 1-64 µg/mL.

Here's the breakdown of the requested information:

1. A table of acceptance criteria and the reported device performance

The document refers to Essential Agreement (EA) and Category Agreement (CA) as performance metrics, comparing the Phoenix System to the CLSI reference broth microdilution method. While the specific numerical acceptance criteria (e.g., "EA > 90%") for these metrics are not explicitly stated as "acceptance criteria" in the text, it can be inferred that they are the benchmarks used for substantial equivalence. The document states a general intra-site reproducibility of "greater than 90%" and inter-site reproducibility of "greater than 95%". For the clinical study, the performance is summarized in a table, but the table itself is corrupted in the input and doesn't show readable performance percentages. However, the text explicitly states: "The data collected from the substantial equivalence studies demonstrate that testing on the BD Phoenix™ Automated Microbiology System with this antimicrobial agent is substantially equivalent as outlined in the FDA draft guidance document, 'Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA,' February 5, 2003." This implies that the device met the acceptance criteria stipulated in that guidance.

2. Sample sized used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

• Sample Size (Test Set): The document mentions "clinical, stock and challenge isolates were tested." The corrupted Table 1 likely contained the specific number of isolates ("htends
  110" and "040
  1000" are remnants of what might have been sample counts). Without the readable table, the precise total number of isolates for the test set cannot be determined.
• Data Provenance: The study was conducted "across multiple geographically diverse sites across the United States." The data appears to be prospective, collected for the purpose of demonstrating the device's performance.

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 document does not explicitly state the number of experts or their qualifications. The ground truth for the test set was established by the CLSI reference broth microdilution method, which is a standardized laboratory procedure, not typically an expert consensus based on individual interpretation.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set

Not applicable. The ground truth for the test set relies on a standardized reference laboratory method (CLSI broth microdilution), not on expert adjudication of diagnostic images or interpretations.

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, an MRMC comparative effectiveness study was not done. This device is an automated microbiology system for antimicrobial susceptibility testing, which directly determines the susceptibility, not an AI to assist human readers in interpreting clinical data. Therefore, the concept of "human readers improve with AI vs without AI assistance" does not apply here.

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 designed to provide susceptibility results (MIC values and categorical interpretations S, I, or R) directly. Its performance (Essential Agreement and Category Agreement) was assessed by comparing its results directly against the CLSI reference method. While human involvement is needed to prepare samples and load panels, the interpretation of results by the system itself is automated.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)

The ground truth used was the CLSI reference broth microdilution method (AST panels prepared according to NCCLS M7). This is a well-established, standardized laboratory method considered the gold standard for antimicrobial susceptibility testing.

8. The sample size for the training set

The document does not specify a separate "training set" or its size. In the context of AST systems, "training data" often refers to the historical data and expert rules/algorithms built into the system during its development, rather than a distinct, prospectively tested set. The document focuses on the validation or test set performance.

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

Since no distinct "training set" is mentioned, the method for establishing its ground truth is not described. The system's underlying algorithm for determining susceptibility would have been developed based on scientific principles of microbiology and data from historical testing and expert knowledge, which implicitly forms the basis of its "training."

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