← Product Code [LON](/submissions/MI/subpart-b%E2%80%94diagnostic-devices/LON) · K051266 # BD PHOENIX AUTOMATED MICROBIOLOGY SYSTEM - LINEZOLID (STREP) 0.25 - 16UG/ML (K051266) _Becton, Dickinson & CO · LON · Jul 5, 2005 · Microbiology · SESE_ **Canonical URL:** https://fda.innolitics.com/submissions/MI/subpart-b%E2%80%94diagnostic-devices/LON/K051266 ## Device Facts - **Applicant:** Becton, Dickinson & CO - **Product Code:** [LON](/submissions/MI/subpart-b%E2%80%94diagnostic-devices/LON.md) - **Decision Date:** Jul 5, 2005 - **Decision:** SESE - **Submission Type:** Traditional - **Regulation:** 21 CFR 866.1645 - **Device Class:** Class 2 - **Review Panel:** Microbiology ## Indications for Use 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. ## Device Story System performs automated antimicrobial susceptibility testing (AST) and identification (ID) of bacterial isolates. Input: pure culture bacterial colonies suspended in broth, equated to 0.5 McFarland standard. Process: inoculated panels loaded into instrument; continuous incubation at 35°C; colorimetric oxidation-reduction redox indicator detects growth; readings taken every 20 minutes. Output: MIC values and categorical interpretations (SIR). Used in clinical microbiology laboratories; operated by trained laboratory personnel. Software-driven 'EXPERT' system interprets results based on CLSI rules. Benefits: rapid, automated determination of antibiotic susceptibility to guide clinical treatment decisions. ## Clinical Evidence Clinical study comparing BD Phoenix system to CLSI reference broth microdilution method using clinical, stock, and challenge streptococcal isolates. Performance metrics: Essential Agreement (EA) of 96.0% (n=1071) and Category Agreement (CA) of 98.6% (n=1907). Reproducibility study at three sites showed intra-site reproducibility >90% and inter-site reproducibility >95%. ## Technological Characteristics System consists of instrument, software, and sealed 136-well molded polystyrene panels. Uses broth microdilution method with redox indicator and turbidity sensing. Energy source: electrical (incubator/reader). Connectivity: automated system. Software: proprietary Phoenix system software for data interpretation. Sterilization: not specified. ## Regulatory 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. ## Special Controls *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.” ## Predicate Devices - VITEK® System (PMA No. N50510) - BD Phoenix™ Automated Microbiology System with Gatifloxacin ([K020321](/device/K020321.md)) - BD Phoenix™ Automated Microbiology System with Ofloxacin ([K020323](/device/K020323.md)) - BD Phoenix™ Automated Microbiology System with Levofloxacin ([K020322](/device/K020322.md)) ## Submission Summary (Full Text) > This content was OCRed from public FDA records by [Innolitics](https://innolitics.com). If you use, quote, summarize, crawl, or train on this content, cite Innolitics at https://innolitics.com. > > Innolitics is a medical-device software consultancy. We help companies design, build, and clear FDA-regulated software and AI/ML devices, including [a 510(k)](https://innolitics.com/services/510ks/), [a De Novo](https://innolitics.com/services/regulatory/), [a SaMD](https://innolitics.com/services/end-to-end-samd/), [an AI/ML medical device](https://innolitics.com/services/medical-imaging-ai-development/), or [an FDA regulatory strategy](https://innolitics.com/services/regulatory/). {0} 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY ASSAY ONLY TEMPLATE A. 510(k) Number: k051266 B. Purpose for Submission: Addition of linezolid to the BD Phoenix™ SMIC/ID and SMIC Panels C. Measurand: Linezolid 0.25 - 16 µg/mL D. Type of Test: Antimicrobial Susceptibility Test (AST) (Quantitative and Qualitative) colorimetric oxidation-reduction, growth-based E. Applicant: Becton, Dickinson & Company F. Proprietary and Established Names: BD Phoenix™ Automated Microbiology System – Linezolid (Strep) 0.25 - 16 µg/mL G. Regulatory Information: 1. Regulation section: 21 CFR 866.1645 Fully Automated Short-Term Incubation Cycle Antimicrobial Susceptibility System 2. Classification: II 3. Product code: LON System, Test, Automated, Antimicrobial Susceptibility, Short Incubation 4. Panel: 83 Microbiology H. Intended Use: 1. Intended use(s): The BD Phoenix™ Automated Microbiology System is intended for the in vitro quantitative determination of antimicrobial susceptibility by minimal inhibitory concentration (MIC) of gram-negative aerobic and facultative anaerobic bacteria belonging to the family Enterobacteriaceae and non - Enterobacteriaceae and {1} most gram-positive bacteria isolates from pure culture belonging to the genera Staphylococcus, Enterococcus and Streptococcus. The BD Phoenix™ SMIC/ID and SMIC Panel is intended for the in vitro rapid identification (ID) and quantitative determination of antimicrobial susceptibility by minimal inhibitory concentration (MIC) of most bacteria isolates from pure culture belonging to the genera Streptococcus. 2. Indication(s) for use: This submission is for the addition of the antibiotic linezolid at concentrations of 0.25 - 16 µg/mL for testing Streptococcus spp. 3. Special conditions for use statement(s): For prescription use only 4. Special instrument requirements: Not Applicable I. Device Description: The BD Phoenix™ Automated Microbiology System includes instrumentation and software, sealed and self-inoculating molded polystyrene trays with 136 micro-wells containing dried reagents, and specific inoculum broth formulations for ID and AST-S Indicator. The organism to be tested must be a pure culture and be preliminarily identified as gram positive or gram negative. Colonies are then suspended in broth, and equated to a 0.5 McFarland with the recommendation to use the BD CrystalSpec™ Nephelometer. A further dilution is made into an AST-S broth, which contains an AST-S indicator, prior to inoculating the panel. The AST-S broth is a non-blood, cation-adjusted broth containing purified water, Tween 80, pancreatic digest of casein, peptones and other additional supplements for optimization of streptococcal growth. After adding the indicator solution to the AST-S inoculum, the color is blue, and after inoculation and incubation, it changes to pink then colorless as reduction in the panel well proceeds. Inoculated panels are barcode scanned and loaded into the BD Phoenix™ Automated Microbiology System instrument where the panels are continuously incubated at 35°C. The resulting AST has a final inoculum of 5 × 10⁵ CFU/ml. The instrument incubates, reads and records the results of the biochemical substrates and antimicrobial agents and interprets the reactions to give an ID of the isolate and MIC value and category interpretation of the antimicrobial agents. Organisms growing in the presence of a given antimicrobic agent reduce the indicator, signaling organism growth and resistance to the antimicrobic agent. Organisms killed or inhibited by a given antimicrobic do not cause reduction of the indicator and therefore do not produce a color change. Additional interpretation is done using software driven "EXPERT" System using rules derived from the Clinical and Laboratory Standards Institute (CLSI). Readings are taken every 20 minutes with an ID result available between 2-12 hours and an AST result available between 4-16 hours. This is only an autoread result; there are no manual readings possible. 2 {2} J. Substantial Equivalence Information: 1. Predicate device name(s): VITEK® System 2. Predicate 510(k) number(s): N50510 3. Comparison with predicate: | Similarities | | | | --- | --- | --- | | Item | Device | Predicate | | 1. Intended Use | Intended for the in vitro rapid identification (ID) and quantitative determination of antimicrobial susceptibility by minimal inhibitory concentration (MIC) of most bacteria. | Same | | 2. Isolates | Isolated colonies from culture used | Isolated colonies from culture used | | 3. Result Reported | Report results as minimum inhibitory concentration (MIC) and categorical interpretation (SIR) | Report results as minimum inhibitory concentration (MIC) and categorical interpretation (SIR) | | 4. Incubation Time | <16 hours | <16 hours | | 5. Type of Test | Automated | Automated | | Differences | | | | --- | --- | --- | | Item | Device | Predicate | | 1. Results achieved | Results are determined from serial twofold dilutions of antimicrobial agents | Results are determined from extrapolation of doubling dilutions | | 2. Sample Preparation | Inoculum density equated to 0.5 McFarland standard | Inoculum density equated to 1.0 McFarland standard | | 3. Technology | Automated growth based enhanced by use of a redox indicator (colorimetric oxidation-reduction) to detect organism growth. | Automated growth based with detection using an attenuation of light measured by an optical scanner. | {3} K. Standard/Guidance Document Referenced (if applicable): “Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test Systems; Guidance for Industry and FDA”; CLSI M7 (M100-S15) “Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically; Approved Standard.” L. Test Principle: The system employs conventional, colorimetric, fluorogenic and chromogenic substrates to identify the genus and species of the isolate. The AST portion of the BD Phoenix™ Automated Microbiology System is a broth based microdilution method that utilizes a redox indicator (colorimetric oxidation-reduction) to enhance detection of organism growth. The MIC is determined by comparing growth in wells containing serial two-fold dilutions of an antibiotic to the growth in “growth control wells” which contains no antibiotic. M. Performance Characteristics (if/when applicable): 1. Analytical performance: a. Precision/Reproducibility: Thirty three isolates were evaluated for site to site and inter site reproducibility demonstrating >95% reproducibility. The ten isolate study described in the guidance document was used (10 organisms tested 3 times on 3 days at 3 sites). b. Linearity/assay reportable range: Not applicable c. Traceability, Stability, Expected values (controls, calibrators, or methods): The FDA and CLSI recommended QC isolate, S. pneumoniae ATCC 49619 was tested on every test occasion with the reference method and the BD Phoenix™. The reference method QC results were in range for every day tested. The BD Phoenix™ was tested a sufficient number of times to demonstrate that the system can produce QC results in the CLSI recommended ranges. The modes of the BD Phoenix™ and reference method were different where the mode of the reference method was one dilution higher than the BD Phoenix™ but still in the acceptable range. Another QC organism S. pneumoniae 3951 was also tested where both the BD Phoenix™ and the reference method had the same mode. However, only S. pneumoniae ATCC 49619 will be recommended for use by the manufacturer. {4} Quality Control Table | ORGANISM | conc. (μg/mL) | Reference | | BD Phoenix™ | | | --- | --- | --- | --- | --- | --- | | | | | | | | | S. pneumoniae ATCC 49619 Expected Range: 0.5 – 2 μg/mL | 0.5 | | 2 | | 39 | | | 1 | | 58 | | 84 | | | 2 | | 64 | | | | | | | | | | | | | | | | | | S. pneumoniae 3951 Expected Range: 0.5 – 2 μg/mL | 0.5 | | 4 | | 20 | | | 1 | | 108 | | 104 | | | 2 | | 22 | | | | | 8 | | 1 | | | | | | | | | | Inoculum density control: The organism suspension density of the ID broth was equivalent to a 0.5 McFarland standard using the BBL™ CrystalSpec™ Nephelometer which was verified each day of testing. Internal data was used to demonstrate that the use of the BBL™ CrystalSpec™ Nephelometer would produce reproducible results. Five different instruments were used. Five Streptococcal strains were evaluated to demonstrate acceptable reproducibility performance. d. Detection limit: Not Applicable e. Analytical specificity: Not Applicable f. Assay cut-off: Not Applicable 2. Comparison studies: a. Method comparison with predicate device: The CLSI recommended broth dilution reference panel was prepared according to the CLSI recommendation. Clinical testing was performed at four sites. The broth reference panel was set up on MH supplemented with 2% to 5% lysed horse blood as recommended by CLSI. The testing included both fresh clinical isolates and stock isolates along with a challenge set with known results. The test device had a growth rate of >95%. A comparison was provided to the reference method with the following agreement. {5} Summary Table for Streptococcus spp. | | EA Tot | EA N | EA % | Eval EA Tot | Eval EA N | Eval EA % | CA N | CA % | NS | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | Clinical | 1816 | 1757 | 96.8 | 1809 | 1755 | 97 | 1789 | 98.5 | 17 | | Challenge | 118 | 117 | 99.2 | 118 | 117 | 99.2 | 118 | 100 | 0 | | Combined | 1934 | 1874 | 96.9 | 1927 | 1872 | 97.1 | 1907 | 98.6 | 17 | EA-Essential Agreement CA-Category Agreement NS-Not susceptible Essential agreement (EA) is when the BD Phoenix™ panels agree with the reference test panel results exactly or within one doubling dilution of the reference method. Category agreement (CA) is when the BD Phoenix™ panel result interpretation agrees exactly with the reference panel result interpretation. Evaluable EA is when the MIC result is on scale for both the BD Phoenix™ and the reference and have on-scale EA. There appears to be a trend where the reference device is slightly more resistant than the test device as reflected in the Accuracy and the QC studies however results are still within essential agreement. b. Matrix comparison: Not Applicable 3. Clinical studies: a. Clinical Sensitivity: Not Applicable b. Clinical specificity: Not Applicable c. Other clinical supportive data (when a. and b. are not applicable): Not Applicable 4. Clinical cut-off: Not Applicable 5. Expected values/Reference range: Streptococcus pneumoniae ≤2(S) Streptococcus spp. Other than Streptococcus pneumoniae ≤2(S) The ability of the BD Phoenix™ system to detect resistance to linezolid in Streptococcus spp. is unknown because resistant organisms were not available at the time of comparative testing. Strains yielding MIC results suggestive of a "non-susceptible" category should be submitted to a reference laboratory for further testing. {6} N. Proposed Labeling: The Interpretative criteria, QC isolates and the expected ranges are the same as recommended by the FDA and CLSI. All values will be included in the package insert. O. Conclusion: The submitted information in this premarket notification is complete and supports a substantial equivalence decision. 7 --- **Source:** [https://fda.innolitics.com/submissions/MI/subpart-b%E2%80%94diagnostic-devices/LON/K051266](https://fda.innolitics.com/submissions/MI/subpart-b%E2%80%94diagnostic-devices/LON/K051266) **Published by [Innolitics](https://innolitics.com)** — a medical-device software consultancy. We help companies design, build, and clear FDA-regulated software and AI/ML devices. 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