(61 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 and Enterococcus.
This premarket notification is for the addition of the antimicrobial agent erythromycin at concentrations of 0.0625-8 ug/mL to Gram Positive ID/AST or AST only Phoenix panels. Erythromycin 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
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 Phocnix 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 Phocnix pancl is a sealed and self-inoculating molded polystyrene tray with 136 micro-wclls The I nooms panet is a scared and oes for susceptibility testing must be a pure culture and comlaining uried reagents. Organisms for sassephenty volumes
preliminarily identified as a Gram-negative or Gram-positive isolate. For each isolation premimatiry received standard is prepared in Phocnix ID broth.
The Phoenix AST method is a broth based microdilution test. The Phoenix System utilizes a redox The I nochis AST memor is a crown around in the presence of an antimicrobial agent. indicator for the delection of organism growth in the preserial turbidity are used in the determination Measurents of Changes to the marcace ageral 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 110 mstrument 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 for the BD Phoenix™ Automated Microbiology System for use with erythromycin were established by comparing its performance against the NCCLS reference broth microdilution method. The study aimed to demonstrate substantial equivalence to this reference method.
Here's a breakdown of the requested information:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are implied by the "Essential Agreement (EA)" and "Category Agreement (CA)" metrics. For the device to be considered substantially equivalent, these agreements should generally be high. While specific numeric thresholds for acceptance are not explicitly stated, the summary of substantial equivalence concludes that the device demonstrated substantially equivalent performance.
| Metric | Acceptance Criteria (Implied) | Reported Device Performance (Erythromycin) |
|---|---|---|
| Essential Agreement (EA) | High agreement with reference method | 95.7% (n=1211) |
| Category Agreement (CA) | High agreement with reference method | 95.7% (n=1132) |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set:
- For Essential Agreement (EA): 1211 isolates.
- For Category Agreement (CA): 1132 isolates.
- Data Provenance: Clinical, stock, and challenge isolates were tested across multiple geographically diverse sites within the United States. The study compared the Phoenix System results to the NCCLS reference broth microdilution method. This indicates a prospective collection of data, likely collected specifically for this validation study, using a mix of real-world (clinical) and controlled (stock, challenge) samples.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not specify the number or qualifications of experts used to establish the ground truth. It states that the "NCCLS reference broth microdilution method" was used as the comparator, which is a standardized laboratory procedure, not typically an expert consensus per se. The implementation and interpretation of this reference method would be carried out by trained laboratory personnel.
4. Adjudication Method for the Test Set
The document does not describe an adjudication method for the test set. The comparison is directly between the Phoenix System results and the NCCLS reference method. Discrepancies between the two would be analyzed as part of the Essential and Category Agreement calculations, but there's no mention of a separate expert adjudication process to resolve disagreements.
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 device described (BD Phoenix™ Automated Microbiology System) is an automated system for antimicrobial susceptibility testing, which does not involve human "readers" in the interpretation of results in the way a diagnostic imaging AI might. It is designed to provide automated interpretations (S, I, R, or N). Therefore, an MRMC study with human readers assessing AI assistance is not relevant here.
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 describes the performance of the "BD Phoenix Aotomated Microbiology System" (which contains the "BD Phoenix instrument and software") in isolation, comparing its automated results directly to the reference method. There is no mention of human-in-the-loop performance being part of this primary evaluation.
7. The Type of Ground Truth Used
The ground truth used was the NCCLS reference broth microdilution method. This is a reference standard method for antimicrobial susceptibility testing, widely accepted in microbiology.
8. The Sample Size for the Training Set
The document does not provide information about a separate training set. The study describes "Clinical, stock and challenge isolates" used for the performance evaluation. For devices like this, the "training" (i.e., algorithm development and optimization) would have been conducted prior to this substantial equivalence study, and the data used for that would typically not be part of the regulatory submission's clinical performance evaluation. This document focuses on the validation of the finalized device.
9. How the Ground Truth for the Training Set Was Established
Since information on a specific training set size is not provided, the method for establishing its ground truth is also not detailed. However, it is highly probable that if a training set were used to develop the Phoenix System's algorithms, the ground truth would have similarly been established using a recognized reference method like the broth microdilution method or other validated laboratory techniques.
§ 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.”