(114 days)
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 Gram-positive aerobic and facultative anaerobic bacteria isolates from pure culture belonging to the genera Staphylococcus and Enterococcus.
This premarket notification is for the addition of the antimicrobial agent trimethoprim-sulfamethoxazole at concentrations of 0.5/9.5 - 16/304 ug/mL to Gram Positive ID/AST or AST only Phoenix panels.
The BD Phoenix Automated Microbiology System (Phoenix System) is an automated system for the 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 consumable supplies and reagents 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, R or N (susceptible, intermediate, resistant or not susceptible).
Here's a breakdown of the acceptance criteria and the study details for the BD Phoenix™ Automated Microbiology System – Trimethoprim-sulfamethoxazole (0.5/9.5 - 16/304 µg/mL), based on the provided 510(k) summary:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria for antimicrobial susceptibility devices are typically based on Essential Agreement (EA) and Category Agreement (CA) when compared to a recognized reference method (in this case, the NCCLS reference broth microdilution method). While numerical thresholds for acceptance criteria (e.g., "EA must be >90%") are often implied or stated in guidance documents, they are not explicitly presented as a hard table of acceptance criteria in this summary. However, the study aims to demonstrate "substantially equivalent performance," which implies meeting common industry and regulatory expectations for these metrics.
| Metric | Implied Acceptance Criteria (typical for AST devices, not explicitly stated numerically as AC in text but implied by "substantially equivalent") | Reported Device Performance |
|---|---|---|
| Essential Agreement (EA) | High percentage (e.g., often >90% or >95% for AST devices) | 96.4% |
| Category Agreement (CA) | High percentage (e.g., often >90% or >95% for AST devices) | 97.9% |
| Intra-site Reproducibility | >90% | >90% |
| Inter-site Reproducibility | >95% | >95% |
Definitions from the text:
- Essential Agreement (EA): Occurs when the BD Phoenix™ Automated Microbiology System agrees exactly or within ± one doubling dilution to the reference result (MIC).
- Category Agreement (CA): Occurs when the BD Phoenix™ Automated Microbiology System agrees with the reference method with respect to the FDA categorical interpretive criteria (susceptible, intermediate, resistant or not susceptible).
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Sample Size: The "n" value reported for Essential Agreement (EA) and Category Agreement (CA) for Trimethoprim-sulfamethoxazole is 634. This represents the total number of isolates tested for this specific antimicrobial agent.
- Data Provenance: The study was conducted across "multiple geographically diverse sites across the United States." This indicates the data is prospective in nature, as it was specifically collected for this performance validation.
3. Number of Experts Used to Establish 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. The ground truth (reference method) was the NCCLS reference broth microdilution method, which is a standardized laboratory technique. While skilled microbiologists would perform this reference method, the document does not detail specific "experts" in the sense of clinical reviewers adjudicating individual cases.
4. Adjudication Method for the Test Set
There is no mention of an adjudication method like "2+1" or "3+1" because the ground truth was established by the NCCLS reference broth microdilution method, which is a laboratory assay. This method inherently produces a definitive result (MIC and categorical interpretation) based on established protocols, rather than requiring expert consensus or adjudication of subjective interpretations.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No, an MRMC comparative effectiveness study was not done. This type of study is more common for imaging devices where human readers interpret results, and the AI's role is to assist human interpretation.
- The Phoenix System is an automated device designed to replace manual susceptibility testing or provide results quickly, not to assist human readers in interpreting an image or complex finding. Therefore, the effect size of human readers improving with AI vs. without AI assistance is not applicable here.
6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study
- Yes, a standalone study was performed. The study directly compares the performance of the BD Phoenix™ Automated Microbiology System's automated results (algorithm only) against the NCCLS reference method. There is no mention of human intervention or interpretation of the Phoenix system's outcome; the system directly provides the MIC and category interpretation.
7. Type of Ground Truth Used
The primary ground truth used for performance comparison was the NCCLS reference broth microdilution method. This is a recognized and standardized laboratory method for determining antimicrobial minimum inhibitory concentrations (MICs) and corresponding categorical interpretations (Susceptible, Intermediate, Resistant). For "Challenge set isolates," the Phoenix System results were compared to "expected results," which presumably refers to established values for known strains.
8. Sample Size for the Training Set
The document does not provide information regarding the sample size used for the training set. This is common for older 510(k) summaries, especially for devices where the underlying technology (e.g., redox indicator for growth detection) relies more on established biophysical principles and empirically derived thresholds than on machine learning models requiring large labeled training datasets.
9. How the Ground Truth for the Training Set Was Established
Since the document does not mention a training set or its size, it also does not specify how the ground truth for any potential training set was established. It's plausible that the system's underlying logic and thresholds were developed through extensive R&D and validation against reference methods, but a formal "training set" in the modern AI/ML sense is not detailed.
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510(k) SUMMARY
| SUBMITTED BY: | Becton, Dickinson and Company7 Loveton CircleSparks, MD 21152Phone: 410-316-4260Fax: 410-316-4499 |
|---|---|
| CONTACT NAME: | Kathryn Babka Powers,RA Specialist |
| DATE PREPARED: | December 16, 2003 |
| DEVICE TRADE NAME: | BD Phoenix™ Automated Microbiology System –Trimethoprim-sulfamethoxazole 0.5/9.5 - 16/304 µg/mL |
| DEVICE COMMON NAME: | Antimicrobial susceptibility test system-short incubation |
| DEVICE CLASSIFICATION: | Fully Automated Short-Term Incubation Cycle AntimicrobialSusceptibility Device, 21 CFR 866.1645 |
| PREDICATE DEVICES: | VITEK® System (PMA No. N50510) and BD Phoenix™Automated Microbiology System with Gatifloxacin (K020321May 23, 2002), Ofloxacin (K020323, April 14, 2002), andLevofloxacin (K020322, March 27, 2002). |
| INTENDED USE: | The BD Phoenix™ Automated Microbiology System isintended for the rapid identification and in vitro antimicrobialsusceptibility testing of isolates from pure culture of mostaerobic and facultative anaerobic Gram-negative and Gram-positive bacteria of human origin. |
DEVICE DESCRIPTION:
The BD Phoenix Automated Microbiology System (Phoenix System) is an automated system for the The DD I nochia Ratomated neceptibility testing (AST) of clinically relevant bacterial isolates. The system includes the following components:
- BD Phoenix instrument and software. .
- DD Phoenix manufacem and in the micals for organism ID testing and antimicrobial agents . or AST determinations.
- of AD r deceminations.
BD Phoenix ID Broth used for performing ID tests and preparing AST Broth inoculum. . - BD Phoenix AST Broth used for performing AST tests only. .
- DD Phoenix AST Indicator solution added to the AST Broth to aid in bacterial growth . determination.
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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. Measurernents 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).
DEVICE COMPARISON:
The BD Phoenix™ Automated Microbiology System demonstrated substantially equivalent performance when compared with the NCCLS reference broth microdilution method. This premarket notification provides data supporting the use of the BD Phocnix™ Automated Microbiology System Gram positive ID/AST or AST only Phoenix panels with this antimicrobial agent.
SUMMARY OF SUBSTANTIAL EQUIVALENCE TESTING:
The BD Phoenix™ Automated Microbiology System has demonstrated substantially equivalent performance when compared to the NCCLS reference broth microdilution method (AST panels prepared according to NCCLS M7). The system has been cvaluated as defined in the FDA Draft guidance document, "Guidance on Review Criteria for Assessment of Antimicrobial Susceptibility Devices", March 8, 2000.
Site Reproducibility
Intra- and inter-site reproducibility of this antimicrobial agent in the BD Phoenix System was evaluated at three sites using a panel of Gram-positive isolates. Each site tested the isolates in triplicate on three different days using one lot of Gram Positive Phoenix panels containing this antimicrobial agent and associated reagents.
The results of the study demonstrate for this antimicrobial agent there was an overall intra-site reproducibility of greater than 90% and an overall inter-site reproducibility greater than 95% for the Gram-positive isolates tested.
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Clinical Studies
Clinical, stock and challenge isolates were tested across multiple geographically diverse sites across the United States to demonstrate the performance of the Phoenix antimicrobial susceptibility test with the Gram Positive Phoenix Panel format containing this antimicrobial agent. Phoenix System results for Challenge set isolates were compared to the expected results. Phoenix System results for clinical isolates were compared to the results obtained from the NCCLS reference broth microdilution method.
The performance of the Phoenix System was assessed by calculating Essential Agreement (EA) and I he percentialied of the expected/reference results for all isolates tested. Essential Agreement Category Figrounnen (12) 10 mix™ Automated Microbiology System agrees exactly or within ± (121) ve fold dilution to the reference result. Category Agreement (CA) occurs when the BD Phocnix™ Automated Microbiology System agrees with the reference method with respect to the FDA categorical interpretive criteria (susceptible, intermediate, resistant or not susceptible).
Table 1 summarizes the performance for the isolates tested in this study.
Performance of BD Phoenix System for Gram-Positive Organisms by Drug Table 1:
| Antimicrobial | Concentration | EA (n) | EA (%) | CA (n) | CA (%) |
|---|---|---|---|---|---|
| Trimethoprim-sulfamethoxazole | 0.5/9.5 - 16/304 µg/mL | 634 | 96.4 | 634 | 97.9 |
Conclusions Drawn from Substantial Equivalence Studies
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, "Guidance on Review Criteria for Assessment of Antimicrobial Susceptibility Devices", March 8, 2000. Technological characteristics of this system are substantially equivalent to those used in the VITEK® system, which received approval by the FDA under PMA number N50510 and BD Phoenix™ Automated Microbiology System with Gatifloxacin (K020321, May 23, 2002), Ofloxacin (K020323, April 14, 2002), and Levofloxacin (K020322, March 27, 2002).
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DEPARTMENT OF HEALTH & HUMAN SERVICES
Image /page/3/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a circular seal with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES USA" around the perimeter. Inside the circle is an abstract symbol resembling an eagle or bird-like figure with three stylized lines forming its body and wings.
Public Health Service
Food and Drug Administration 2098 Gaither Road Rockville MD 20850
APR - 9 2004
Ms. Kathryn Babka Powers Regulatory Affairs Specialist BD Diagnostics Systems Becton, Dickinson and Company 7 Loveton Circle Sparks, MD 21152
Re: K033907
Trade/Device Name: BD Phoenix TM Automated Microbiology System Trimethoprim-sulfamethoxazole (0.5/9.5-16/304 ug/mL) Regulation Number: 21 CFR 866.1645 Regulation Name: Fully Automated Short-Term Incubation Cycle Antimicrobial Susceptibility Devices Regulatory Class: Class II Product Code: LON Dated: April 2, 2004 Received: April 5, 2004
Dear Ms. Powers:
We have reviewed your Section 510(k) premarket notification of intent to mailet the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food. Drug. and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA). it may be subject to such additional controls. Existing major regulations affecting your device can be found in Title 21, Code of Federal Regulations (CFR), Parts 800 to 895. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Parts 801 and 809); and good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820).
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Page 2
This letter will allow you to begin marketing your device as described in your Section 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.
If you desire specific information about the application of labeling requirements to your device, or questions on the promotion and advertising of your device, please contact the Office of In Vitro Diagnostic Device Evaluation and Safety at (301) 594-3084. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html.
Sincerely yours,
Saartys
Sally A. Hojvat, M.Sc., Ph.D. Director Division of Microbiology Devices Office of In Vitro Diagnostic Device Evaluation and Safety Center for Devices and Radiological Health
Enclosure
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INDICATIONS FOR USE
510(k) Number (if known): k033907_____________________________________________________________________________________________________________________________________________
Device Name: BD Phoenix™ Automated Microbiology System for use with the antimicabial agent Device Name: BD Phoemx --- Automated Mr.001010B) - Gram positive ID/AST or AST only Phoenix Panels.
Indications for Use:
The BD Phoenix™ Automated Microbiology System is intended for in virro quantitative determination of The BD Phoenix™ Automated Microbiology System is interation (MIC) of most Gram-negative actobic and antimicrobial susceptibility by minimal in the releveleriaceae and Non-Entervolacteriaceae
facultative anaerobic bacteria isolates from pure culture for Enterobacteriaceae an tacultative anaeronic bacteria isolates from pure culture belonging to the genera Staphylococcus and Enterococcus.
This premarket notification is for the antimiorobial agent trimethoprim-sulfamethoxazole at I his premarket notification is for the addition of the antive ID/AST or AST only Phoenix panels. concentrations of U.>/9.5 - 10/304 ug/mL to Grain Form & Feb 20 gainst most strains of microorganisms listed below.
Active In Vitro Against:
Staphylococcus aureus
Prescription Use
(Part 21 CFR 801 Subpart D)
Over-the-Counter Use (21 CFR 807 Subpart C)
(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)
Concurrence of CDRH, Office of In Vitro Diagnostic Devices (OIVD)
Welcome Clearly for Sally Hojvat
Division Sign-Off
Office of In Vitro Diagnostic Device Evaluation and Safety
510(k) K033907
§ 866.1645 Fully automated short-term incubation cycle antimicrobial susceptibility system.
(a)
Identification. A fully automated short-term incubation cycle antimicrobial susceptibility system is a device that incorporates concentrations of antimicrobial agents into a system for the purpose of determining in vitro susceptibility of bacterial pathogens isolated from clinical specimens. Test results obtained from short-term (less than 16 hours) incubation are used to determine the antimicrobial agent of choice to treat bacterial diseases.(b)
Classification. Class II (special controls). The special control for this device is FDA's guidance document entitled “Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA.”