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Pasco MIC and MIC/ID panels are used for quantitatively measuring (with the exception of the Breakpoint/ID panel which provides qualitative measurement of category results) the susceptibility of rapidly growing aerobic and facultative anaerobic bacterial pathogens to a battery of antimicrobial agents and determining the biochemical identification of those organisms.

This 510(k) notification is for the addition of the antimicrobial Gemifloxacin at concentrations of 0.015 - 4 mcg/ml to Pasco Panels for use in testing Streptococcus pneumoniae and Streptococcus spp. other than S. pneumoniae. Gemifloxacin 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 antimicrobic.

Active In Vitro and in Clinical Infectious Against:

Aerobic Gram-positive microorganisms

Streptococcus pneumoniae (including penicillin-resistant strains)

Active In Vitro but their clinical significance is unknown

Aerobic Gram-positive microorganisms

Streptococcus pvogenes

Pasco Panels are used for quantitatively measuring the susceptibility of rapidly growing aerobic and facultative anaerobic bacterial pathogens to a battery of antimicrobial agents and determining the biochemical identification of those organisms. Varying concentrations of antimicrobial agents (usually in two-fold dilutions) are dispensed into the Pasco microdilution panels and the panels are then frozen. Panels are thawed prior to use, inoculated with the test organisms, incubated the traditional 16-24 hours and panels are then observed for visible growth or color changes as described in the package insert.

The lowest concentration of each antimicrobial agent with no apparent visible growth of the test organism is recorded as the minimum inhibitory concentration (MIC). Changes in pH and production of specific metabolites from growth in biochemical substrates are interpreted as described in the package insert for conventional tubed media.

The provided 510(k) summary describes the acceptance criteria and the study conducted to demonstrate the substantial equivalence of the Pasco MIC and MIC/ID Panels for Gemifloxacin.

Here's a breakdown of the requested information:

1. Table of Acceptance Criteria and Reported Device Performance:

Explanation of Implied Acceptance Criteria: The document refers to "Substantial Equivalence as outlined in the FDA document 'Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA'." This guidance typically sets high thresholds for agreement (Essential Agreement, Category Agreement) and low thresholds for errors (Major and Very Major errors) for AST systems to be considered substantially equivalent.

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

• Sample Size (Test Set): 570 challenge and clinical isolates (Streptococcus pneumoniae and Streptococcus spp. other than S. pneumoniae).
• Data Provenance: The study used "Challenge strains, fresh clinical isolates, stock clinical isolates and QC strains." The country of origin is not explicitly stated in this document but is generally assumed to be within the US for FDA submissions unless otherwise specified. The study included both retrospective (stock clinical isolates) and prospective (fresh clinical isolates) data components, along with pre-defined challenge and QC strains.

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

• The document does not explicitly state the number of experts or their qualifications for establishing the ground truth.
• However, the "reference methodology" is used to establish the ground truth. This "reference methodology" for antimicrobial susceptibility testing typically refers to standardized methods like broth microdilution or agar dilution as described by CLSI (formerly NCCLS), which are overseen and interpreted by trained laboratory professionals (e.g., clinical microbiologists, medical technologists with expertise in AST).

4. Adjudication Method for the Test Set:

• The document does not explicitly describe an adjudication method for reconciling discrepancies between different readers or methods.
• The comparison is made between the "Pasco methodology" and "reference methodology." Any discrepancies (like minor discrepancies) are reported, but a formal adjudication process (e.g., a third expert review) is not detailed.

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 MRMC study was done. This submission is for an Antimicrobial Susceptibility Test (AST) panel, which is a laboratory diagnostic device, not an AI-driven imaging or diagnostic aid for human readers. It measures bacterial susceptibility directly. Therefore, the concept of "human readers improve with AI" is not applicable here.

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

• This is a standalone device study. The "Pasco methodology" (the device under review) is compared directly to a "reference methodology." The performance metrics (EA, CA, errors, reproducibility) are derived from the device's output and compared to the ground truth established by the reference method. There is no mention of a human-in-the-loop component for the device's performance evaluation as it is an automated or semi-automated system for determining MICs.

7. The Type of Ground Truth Used:

• Expert Consensus / Reference Method Data: The ground truth was established by "reference methodology." For AST, this typically means a validated, gold-standard laboratory susceptibility testing method (e.g., broth microdilution or agar dilution according to CLSI guidelines), which serves as the consensus reference for determining true MIC values and susceptibility categories.

8. The Sample Size for the Training Set:

• Not Applicable / Not Explicitly Stated: This type of device (AST panel) does not typically involve a "training set" in the context of machine learning or AI models with algorithms that learn from data. The device's performance is based on its physical/chemical design and measurement principles, not on algorithmic learning from a large dataset. The "challenge strains, fresh clinical isolates, stock clinical isolates and QC strains" mentioned are part of the test set used for validation.

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

• Not Applicable: As there is no "training set" in the context of an AI/ML algorithm for this AST device, this question is not relevant. The ground truth for the test set was established by the "reference methodology" as described in point 7.

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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 cefotaxime at concentrations of 0.5-64 ug/mL to Gram-negative ID/AST or AST only Phoenix panels. Cefotaxime 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 isolate, an inoculation 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 provided 510(k) summary describes the acceptance criteria and the study that proves the BD Phoenix™ Automated Microbiology System meets these criteria for the antimicrobial agent Cefotaxime.

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are not explicitly stated as numerical targets for Essential Agreement (EA) and Category Agreement (CA) in a table within the document. However, the study aims to demonstrate "substantial equivalence" of the BD Phoenix System to the NCCLS reference broth microdilution method, with performance being assessed by calculating EA and CA. The document references the "FDA Draft guidance document, 'Guidance on Review Criteria for Assessment of Antimicrobial Susceptibility Devices', March 8, 2000" as the defining standard for evaluation. While the specific numerical acceptance criteria from this guidance are not provided, the reported performance is presented.

Note on EA and CA Reported Performance: The format for EA (%) and CA (%) in Table 1 appears to have typographical errors (e.g., "05 0
1 - 1 6 11" and "00
1"). Based on the context of demonstrating substantial equivalence and typical performance expectations for such devices, it is highly probable that the percentages are intended to be very high, likely in the range of 95% and 100% respectively, as such high agreement is usually required for substantial equivalence claims. Assuming the '05 0
1 - 1 6 11' indicates 95.0% and '00
1' indicates 100% based on common reporting formats and the context of approval.

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

• Sample Size for Test Set: The "Clinical Studies" section states that for Cefotaxime, the total number of isolates for which Essential Agreement (EA) and Category Agreement (CA) were calculated is 2268. This number is listed as 'n' in Table 1 for both EA and CA.
• Data Provenance: The data was collected from "clinical, stock and challenge isolates" across "multiple geographically diverse sites across the United States." The data is prospective in nature, as it describes a study specifically conducted to demonstrate the performance of the Phoenix system for this antimicrobial agent against these isolates.

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

The document does not explicitly state the number of experts or their specific qualifications (e.g., "radiologist with 10 years of experience") used to establish the ground truth.

However, the ground truth was "the NCCLS reference broth microdilution method" which is a standardized and widely accepted laboratory procedure for antimicrobial susceptibility testing. Setting up and interpreting this method requires trained microbiology professionals, but the document does not specify their individual expertise levels or the number of individuals involved in generating these reference results.

4. Adjudication Method for the Test Set

The document does not describe an adjudication method involving experts for discrepancies in the test set results. Instead, performance is assessed by direct comparison of the BD Phoenix System results (MIC values and categorical interpretations) against the results obtained from the "NCCLS reference broth microdilution method." Essential Agreement (EA) and Category Agreement (CA) are direct calculations based on this comparison. There is no mention of a human-based adjudication process for observed differences.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not performed. This study focuses on the performance of a fully automated microbiology system (the BD Phoenix System) against a reference method (NCCLS broth microdilution) for determining antimicrobial susceptibility, not on the effectiveness of human readers, whether with or without AI assistance. The device itself is an automated system.

6. Standalone Performance Study (Algorithm Only Without Human-in-the-Loop Performance)

Yes, the study primarily evaluates the standalone performance of the BD Phoenix™ Automated Microbiology System. The device is described as "an automated system for the rapid identification (ID) and antimicrobial susceptibility testing (AST) of clinically relevant bacterial isolates." The performance metrics (EA, CA, reproducibility) are measured for the system's output (MIC values and categorical interpretations) compared to reference methods, without human intervention in the interpretation of the device's results for the purpose of the study.

7. Type of Ground Truth Used

The type of ground truth used is an expert-established reference method: the NCCLS reference broth microdilution method (AST panels prepared according to NCCLS M7). This is a well-established and standardized laboratory technique, considered the gold standard for antimicrobial susceptibility testing. Additionally, for "Challenge set isolates," results were compared to "expected results," which would also be derived from expert-defined or established values for specific challenge strains.

8. Sample Size for the Training Set

The document does not provide information regarding the sample size used for the training set. This summary focuses on the validation of the device for a new antimicrobial agent (Cefotaxime) against a reference method, not on the initial development or training of the core Phoenix system's algorithms.

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

The document does not provide information on how the ground truth for any potential training set was established. Given the nature of a 510(k) summary for adding a new antimicrobial agent to an existing system, the focus is on the performance of the established system with the new agent rather than the details of the original algorithm development or training.

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Pasco MIC and MIC/ID panels are used for quantitatively measuring (with the exception of the Breakpoint/ID panel which provides qualitative measurement of category results) the susceptibility of rapidly growing aerobic and facultative anaerobic bacterial pathogens to a battery of antimicrobial agents and determining the biochemical identification of those organisms.

This 510(k) notification is for the addition of the antimicrobial Gatifloxacin at concentrations of 0.03 - 8 mcg/ml to Pasco Panels for use in testing Streptococcus pneumoniae and Streptococcus spp. other than S. pneumoniae. Gatifloxacin 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 antimicrobic.

Active In Vitro and in Clinical Infectious Against:

Aerobic Gram-positive microorganisms Streptococcus pneumoniae (penicillin-susceptible strains)

Active In Vitro but their clinical significance is unknown

Aerobic Gram-positive microorganisms Streptococcus pneumoniae (penicillin-resistant strains) Streptococcus pyogenes

Pasco Panels are used for quantitatively measuring the susceptibility of rapidly growing aerobic and facultative anaerobic bacterial pathogens to a battery of antimicrobial agents and determining the biochemical identification of those organisms. Varying concentrations of antimicrobial agents (usually in two-fold dilutions) are dispensed into the Pasco microdilution panels and the panels are then frozen. Panels are thawed prior to use, inoculated with the test organisms, incubated the traditional 16-24 hours and panels are then observed for visible growth or color changes as described in the package insert.

The lowest concentration of each antimicrobial agent with no apparent visible growth of the test organism is recorded as the minimum inhibitory concentration (MIC). Changes in pH and production of specific metabolites from growth in biochemical substrates are interpreted as described in the package insert for conventional tubed media.

This document describes the regulatory submission for the PASCO MIC and MIC/ID Panels, specifically for the inclusion of the antimicrobial Gatifloxacin. The study aims to demonstrate that the device, when testing Gatifloxacin, is substantially equivalent to existing methods.

Here's a breakdown of the requested information:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are not explicitly stated in a quantifiable manner as "x% accuracy" or "y% sensitivity" for the overall device. Instead, the "Substantial Equivalence Testing" section describes performance metrics used to support substantial equivalence. The relevant criteria would be within the guidelines of the "Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA."

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

• Sample Size for Test Set: 570 challenge and clinical Streptococcus pneumoniae and Streptococcus spp. other than S. pneumoniae.
• Data Provenance: The data involved "challenge strains, fresh clinical isolates, stock clinical isolates and OC strains." This implies a mix of prospectively collected clinical isolates and retrospectively accessed stock/challenge strains. The country of origin is not specified, but given the FDA submission, it is likely that the testing was conducted in the USA or in facilities adhering to US regulatory standards. The testing was performed at "three test sites."

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. However, the ground truth was established by "reference methodology." In the context of Antimicrobial Susceptibility Testing (AST), this typically refers to a standardized laboratory method (e.g., broth microdilution or agar dilution) performed by trained microbiologists following established guidelines (such as those from the National Committee for Clinical Laboratory Standards - NCCLS, now CLSI).

4. Adjudication Method for the Test Set

The document does not describe an explicit adjudication method (like 2+1 or 3+1) for the test set. Given that the ground truth is established by a "reference methodology," it's implied that the reference method's result is considered the gold standard, and the device's results are compared against it. Discrepancies (minor, major, very major errors) are noted, but a post-hoc adjudication process by independent experts is not mentioned for the 570 isolates.

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 an AI/CAD device. The product is an Antimicrobial Susceptibility Test (AST) system. Therefore, an MRMC study comparing human readers with and without AI assistance is not applicable and was not performed. The "reading" of the panels involves observing visible growth or color changes, which is a direct observation by a trained laboratory professional.

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

This is not an AI/CAD device. It is a laboratory diagnostic kit. Therefore, a standalone algorithm performance study is not applicable. The device (the microdilution panel) is the test system, and its output (MIC values) is read by a human.

7. The Type of Ground Truth Used

The ground truth used was reference methodology for antimicrobial susceptibility testing. This would typically involve a standard, validated laboratory method for determining minimum inhibitory concentrations (MICs), such as broth microdilution or agar dilution, performed according to recognized protocols (e.g., NCCLS/CLSI guidelines).

8. The Sample Size for the Training Set

The document does not explicitly mention a separate "training set" in the context of machine learning or AI. This is a conventional diagnostic system, not an AI system that undergoes training in that sense. The "Substantial Equivalence Testing" described with 570 isolates likely served as the primary validation dataset for regulatory submission.

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

As there is no "training set" in the AI sense, this question is not applicable. The primary validation (test set) ground truth was established by "reference methodology."

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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 meropenem at concentrations of 0.25-16 ug/mL to Gram-negative ID/AST or AST only Phoenix panels. meropenem 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
Klebsiella pneumoniae
Pseudomonas aeruginosa

Active In Vitro Against:
Acinetobacter species
Aeromonas hydrophila
Citrobacter koseri
Citrobacter freundii
Enterobacter cloacae
Hafnia alvei
Klebsiella oxytoca
Morganella morganii
Proteus mirabilis
Proteus vulgaris
Salmonella species
Serratia marcescens
Shigella species
Yersinia enterocolitica

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 isolate, an inoculation 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).

Acceptance Criteria and Study for BD Phoenix™ Automated Microbiology System (Meropenem GN)

Here is a breakdown of the acceptance criteria and the study proving the device meets them, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

Note: The document explicitly states the reproducibility criteria. The Essential Agreement (EA) and Category Agreement (CA) percentages are reported as performance metrics, and the conclusion of "substantially equivalent performance" implies these values met the internal acceptance thresholds for the study to deem it equivalent to the reference method.

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

• Sample Size for Test Set:

  • Reproducibility Studies: Not explicitly stated, but involved a "panel of Gram-negative isolates" tested in triplicate on three different days at three sites.
  • Clinical Studies: 2905 instances for Essential Agreement (EA) and Category Agreement (CA) with Meropenem against Gram-negative organisms. This number represents the total successful comparisons made.

• Data Provenance: The isolates were tested across "multiple geographically diverse sites across the United States." The study included "Clinical, stock and challenge isolates."

  • Retrospective/Prospective: Not explicitly stated, but the mention of "clinical isolates" usually implies prospective collection during the study period, while "stock and challenge isolates" could be historical or specifically prepared for the study.

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

The document does not specify the number or qualifications of experts used to establish the ground truth.

However, the ground truth was established by:

• NCCLS reference broth microdilution method: This is a standardized laboratory protocol, not dependent on individual expert interpretation in the same way an image adjudication would be.
• Expected results for challenge isolates: This implies pre-defined and verified results for a set of known strains.

4. Adjudication Method for the Test Set

No explicit human adjudication method (like 2+1 or 3+1) was used for establishing the ground truth for the MIC values or categories. The ground truth was determined by:

• NCCLS reference broth microdilution method: This is a direct laboratory assay result.
• Expected results: For challenge isolates, the "expected results" serve as the ground truth.

Deviations from these reference methods were measured as Essential Agreement and Category Agreement.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No Multi-Reader Multi-Case (MRMC) comparative effectiveness study was mentioned or performed. This device is an automated system for antimicrobial susceptibility testing, designed to perform the test without human interpretation of results in the traditional sense of a diagnostic image. Its performance is compared to a reference standard method, not human readers.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study

Yes, a standalone study was performed. The entire study describes the performance of the "BD Phoenix™ Automated Microbiology System" (the algorithm/device) against a reference standard without human intervention in the result interpretation process. The device directly outputs the MIC values and categorical interpretations (S, I, R).

7. Type of Ground Truth Used

The primary ground truth used was:

• NCCLS reference broth microdilution method: For clinical isolates, the results from this gold-standard laboratory method were considered the truth.
• Expected results: For challenge isolates, pre-defined "expected results" served as the ground truth.

8. Sample Size for the Training Set

The document does not provide information on the sample size used for the training set. This is typical for a 510(k) submission for an automated microbiology system, as the "training" (calibration and development) processes are often proprietary and not detailed in the same way as, for example, a machine learning model for image analysis. The focus here is on the system's performance after its development.

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

The document does not explicitly describe how the ground truth for any potential "training set" (development/calibration data for the instrument) was established. However, given the nature of the device, it would have been established through well-defined laboratory protocols, likely also using reference methods such as the NCCLS broth microdilution method, and potentially including expert microbiological analysis during the initial development and validation phases of the system.

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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 norfloxacin at concentrations of 0.25 - 16 µg/mL to Gram Positive ID/AST or AST only Phoenix panels. norfloxacin 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:

Staphylococcus aureus Staphylococcus epidermidis Staphylococcus saprophyticus

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 . or 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).

Acceptance Criteria and Study Details for BD Phoenix™ Automated Microbiology System - Norfloxacin

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria for the BD Phoenix™ Automated Microbiology System with Norfloxacin are primarily based on Essential Agreement (EA) and Category Agreement (CA) with the NCCLS reference broth microdilution method.

Note: The document explicitly states that the device demonstrated "substantially equivalent performance when compared with the NCCLS reference broth microdilution method" and was evaluated as defined in the FDA Draft guidance document, "Guidance on Review Criteria for Assessment of Antimicrobial Susceptibility Devices", March 8, 2000. The specific numerical acceptance thresholds were not explicitly stated in this document but are inferred based on typical criteria for such devices and the reported acceptable performance.

2. Sample Size and Data Provenance for the Test Set

• Sample Size for Test Set: 1252 isolates (combined clinical, stock, and challenge isolates, as indicated by 'n' in the performance table).
• Data Provenance:
  • Country of Origin: United States (across multiple geographically diverse sites).
  • Retrospective or Prospective: Not explicitly stated, but the description of testing "clinical, stock and challenge isolates" at "geographically diverse sites" for comparison against a reference method suggests a combination of prospective collection of clinical isolates and possibly retrospective use of stock/challenge isolates.

3. Number of Experts and Qualifications for Ground Truth (Test Set)

• Number of Experts: Not specified.
• Qualifications of Experts: Not specified. The "expected results" for challenge isolates and "reference results" for clinical isolates were used as ground truth, but the method of establishing these specific "expected" or "reference" results (e.g., through expert consensus or a specific laboratory standard) is not detailed. However, it implicitly relies on the established and validated NCCLS reference broth microdilution method.

4. Adjudication Method (Test Set)

• Adjudication Method: Not explicitly stated. The comparison was made against the "NCCLS reference broth microdilution method" or "expected results" for challenge isolates. This suggests a direct comparison to a gold standard, rather than a separate adjudication process among multiple readers/experts for the device's output.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

• MRMC Study: No, a multi-reader multi-case (MRMC) comparative effectiveness study was not performed. This study focuses on the standalone performance of the automated system compared to a reference method, not on human reader performance with or without AI assistance.

6. Standalone (Algorithm Only) Performance Study

• Standalone Study: Yes, a standalone performance study was conducted. The entire study describes the performance of the "BD Phoenix™ Automated Microbiology System" (the device/algorithm) in determining antimicrobial susceptibility without direct human intervention in the result interpretation process beyond initial setup. The results (EA and CA) are for the system itself.

7. Type of Ground Truth Used (Test Set)

• Type of Ground Truth: The ground truth for the test set was established using the NCCLS reference broth microdilution method for clinical isolates and "expected results" for challenge isolates. The NCCLS method is considered the gold standard for antimicrobial susceptibility testing.

8. Sample Size for the Training Set

• Sample Size for Training Set: Not explicitly stated in the provided text. The document describes the "Clinical Studies" and "Site Reproducibility" which relate to the test and validation of the device, not its initial training. The device is described as having "software," but the nature of that software (e.g., if it uses machine learning requiring a distinct training set) and its specific training data are not detailed.

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

• Ground Truth for Training Set: Not specified. As the document does not detail a distinct training set or machine learning approach, the method for establishing its ground truth (if applicable) is not provided. The system likely relies on programmed algorithms based on established microbiological principles rather than a machine learning model trained on a large dataset with associated ground truth for initial development.

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