(55 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 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, clindamycin, at concentrations of 0.0313-4ug/mL, to Streptococcus ID/AST or AST only Phoenix panels. Clindamycin 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 species, including Pneumococcus 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. 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 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 that proves the device meets them, based on the provided text:
Acceptance Criteria and Device Performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Intra-site reproducibility > 90% | Overall intra-site reproducibility > 90% for clindamycin for streptococcal isolates. |
| Inter-site reproducibility > 95% | Overall inter-site reproducibility > 95% for clindamycin for streptococcal isolates. |
| Essential Agreement (EA) to reference methods | 1047 (Overall EA) |
| Category Agreement (CA) to reference methods | 1017 (Overall CA) |
(Note: The raw numbers for EA and CA are provided as "1047" and "1017" respectively, but the percentage agreement (which is typically the primary metric) is not explicitly given in the table excerpt. However, the text states that performance was assessed by calculating EA and CA, implying these values met the acceptance threshold for substantial equivalence.)
Study Details
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Sample size used for the test set and the data provenance:
- Test Set Size: Not explicitly stated as a single number. The study mentions "Clinical, stock and challenge isolates were tested." The EA and CA values are given as "1047" and "1017" respectively, which likely represent the count of comparisons rather than the number of unique isolates.
- Data Provenance: The isolates were tested "across multiple geographically diverse sites across the United States."
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- This information is not provided in the given text.
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Adjudication method for the test set:
- This information is not provided in the given text. The study compares the Phoenix System results to a "CLSI-recommended reference broth microdilution method" and "expected results" for challenge isolates, implying a direct comparison rather than a multi-reader adjudication process for the ground truth itself.
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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 involving human readers and AI assistance was not done. This device is a fully automated microbiology system for antimicrobial susceptibility testing, not an AI-assisted diagnostic tool for human interpretation.
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If a standalone (i.e. algorithm only without human-in-the loop performance) was done:
- Yes, the study is fundamentally a standalone performance evaluation of the BD Phoenix™ Automated Microbiology System (an automated algorithm/system) against a reference method. There is no human-in-the-loop component described for the primary performance assessment.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- The ground truth for clinical isolates was established by the CLSI-recommended reference broth microdilution method.
- The ground truth for challenge isolates was based on "expected results."
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The sample size for the training set:
- This information is not provided in the given text. The document describes the testing of the device's performance, not the development or training of the device's underlying algorithms.
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How the ground truth for the training set was established:
- This information is not provided in the given text, as the document does not detail the training set or its ground truth establishment.
§ 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.”