(76 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.
This premarket notification is for the addition of the antimicrobial agent daptomycin at concentrations of 0.0313-16 ug/mL to Streptococcus ID/AST or AST only Phoenix panels. Daptomycin 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 agalactiae Streptococcus dysgalactiae Streptococcus pyogenes
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 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),
Here's a breakdown of the acceptance criteria and study details based on the provided 510(k) summary:
Acceptance Criteria and Device Performance
The acceptance criteria for the BD Phoenix™ Automated Microbiology System for the antimicrobial agent daptomycin, when compared to the CLSI reference broth microdilution method, are based on Essential Agreement (EA) and Category Agreement (CA).
| Performance Metric | Acceptance Criteria (Implicit) | Reported Device Performance (Table 1 - Incomplete) |
|---|---|---|
| Essential Agreement (EA) | Not explicitly stated, but typically ≥ 90.0% | Not explicitly stated in Table 1; a placeholder (0) and 11 are present. |
| Category Agreement (CA) | Not explicitly stated, but typically ≥ 90.0% | Not explicitly stated in Table 1; a placeholder 0/0 is present. |
| Intra-site Reproducibility | > 90% | > 90% |
| Inter-site Reproducibility | > 95% | > 95% |
Note on Table 1: The provided Table 1 is incomplete and practically unreadable due to formatting issues and garbled text. It's impossible to extract the precise reported Essential Agreement and Category Agreement percentages for daptomycin from this table. However, the summary concludes that "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," implying that the acceptance criteria for EA and CA were met.
Study Details
2. Sample size used for the test set and the data provenance:
- Test Set Sample Size: The document mentions "clinical, stock and challenge isolates were tested." No specific numbers are provided for the total test set. However, for reproducibility studies, a "panel of streptococcal isolates" was used.
- Data Provenance: The studies were conducted "across multiple geographically diverse sites across the United States." This indicates prospective data collection.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Number of Experts: Not specified.
- Qualifications of Experts: Not specified. The ground truth was established by comparing to the CLSI reference broth microdilution method, which is a standardized laboratory method, not typically relying on expert interpretation in the same way as, for example, image analysis.
4. Adjudication method for the test set:
- Not applicable/Not specified. The comparison is between the device's quantitative MIC values and categorical interpretations and the CLSI reference method. There is no mention of human adjudication for discrepancies.
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 system for antimicrobial susceptibility testing, not an AI-assisted diagnostic imaging or interpretation tool for human readers.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Yes, the study describes a standalone performance evaluation of the BD Phoenix™ Automated Microbiology System. The system automatically measures changes to an indicator and bacterial turbidity to determine MIC values and categorical interpretations. These results are then compared directly to the CLSI reference method. While human lab technicians operate the instrument and prepare samples, the interpretation and determination of susceptibility are automated by the device's algorithm.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- The ground truth was the CLSI (Clinical and Laboratory Standards Institute) reference broth microdilution method. This is a recognized gold standard laboratory method for determining antimicrobial susceptibility. For challenge set isolates, "expected results" were used, which would typically be predetermined MICs for control strains.
8. The sample size for the training set:
- Not applicable/Not specified. This document describes a validation study for a specific antimicrobial agent (daptomycin) on an established automated system. The system's underlying algorithms would have been developed and "trained" previously using extensive data, but this specific submission does not detail the training set for the core Phoenix system or for the addition of this new agent.
9. How the ground truth for the training set was established:
- Not applicable/Not specified, as no training set for this specific submission is detailed. For the development of the broader Phoenix system algorithms, the ground truth would have been established using reference methods like CLSI broth microdilution on a large scale.
§ 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.”