Search Results

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 the addition of the antimicrobial agent moxifloxacin at concentrations of 0.0625-8 ug/mL to Streptococcus ID/AST or AST only Phoenix panels. Moxifloxacin 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:

Streptococcus anginosus Streptococcus constellatus Streptococcus pneumoniae (including multi-drug resistant strains [MDRSP]) Streptococcus pyogenes

Active In Vitro Against:

Streptococcus agalactiae Streptococcus viridans group

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. For testing Streptococcus species the system includes the following components:

• . BD Phoenix instrument and software.
• BD Phoenix panels containing biochemicals for organism ID testing and antimicrobial agents . or AST determinations.
• BD Phoenix ID Broth used for performing ID tests and preparing AST Broth inoculum. .
• . BD Phoenix AST-S Broth used for performing AST tests only.
• BD Phoenix AST-S Indicator solution added to the AST Broth to aid in bacterial growth . determination.

The Phoenix panel is a sealed and self-inoculating molded polystyrene trav 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, R or N (susceptible, intermediate, resistant or not susceptible).

The acceptance criteria and study proving the device meets these criteria for the BD Phoenix™ Automated Microbiology System for moxifloxacin (0.0625-8 µg/mL) with Streptococcus ID/AST or AST only Phoenix panels are described below:

1. Table of Acceptance Criteria and Reported Device Performance

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

• Clinical Studies: The document mentions "Clinical, stock and challenge isolates" were tested.
  • Clinical Isolates: "all isolates tested" and tables showing "1050" isolates for Accuracy and Performance with Moxifloxacin. These were compared to the CLSI reference broth microdilution method.
  • Challenge Isolates: Compared to expected results. The number of challenge isolates is not explicitly stated separately but is implied to be part of the "1050" total if not specified otherwise.
• Reproducibility Studies: "a panel of streptococcal isolates" was used. The exact number is not explicitly stated.
• Data Provenance: "multiple geographically diverse sites across the United States" (for clinical studies). The study type is explicitly a "clinical study" comparing the device to a reference method, which implies prospective data collection for this purpose, though the source of the isolates (e.g., retrospective collection of patient samples) is not detailed.

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

The document does not explicitly state the number of experts or their qualifications for establishing the ground truth. The ground truth was established by:

• CLSI reference broth microdilution method: This method itself is the gold standard for antimicrobial susceptibility testing, implying adherence to a standardized protocol rather than individual expert interpretation for each case.
• Expected results for Challenge isolates: These are typically well-characterized strains with known susceptibility profiles.

4. Adjudication Method for the Test Set

The document does not describe an adjudication method involving multiple experts for discrepant results. Instead, it relies on quantitative comparison metrics (Essential Agreement and Category Agreement) against the CLSI reference method or expected results for challenge isolates. The system determines an MIC value, which is then compared rather than subjective interpretation requiring adjudication.

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

This is not applicable. The BD Phoenix™ Automated Microbiology System is an automated system for identification and antimicrobial susceptibility testing. It is a standalone device that performs these tests without direct human "reading" of the results in the traditional sense or human-in-the-loop performance improvement as seen in AI-assisted diagnostics. The system provides MIC values and categorical interpretations automatically.

6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) Was Done

Yes, a standalone performance study was done. The entire study evaluates the performance of the BD Phoenix™ Automated Microbiology System (an automated device/algorithm) in isolation, comparing its output directly to the CLSI reference broth microdilution method. The system itself determines the MIC values and interpretations.

7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)

The ground truth used was primarily the CLSI reference broth microdilution method for clinical isolates. For challenge isolates, the ground truth was "expected results," which refers to the known susceptibility profile of those well-characterized strains. This is a recognized "gold standard" laboratory method.

8. The Sample Size for the Training Set

The document does not provide information regarding a distinct training set sample size. This type of regulatory submission typically focuses on validation and performance testing rather than the details of algorithm development and training, as the "algorithm" here relates to the system's ability to interpret growth patterns rather than a machine learning model developed with a large labeled dataset in the modern sense. The system's "learning" or calibration would have been done during its development, but these specifics are not part of this 510(k) summary.

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

Given that no specific training set is detailed, the method for establishing its ground truth is also not described. As mentioned in point 8, the submission focuses on the validation of the final device against reference methods rather than the internal development details.

Ask a specific question about this device