← Product Code [LON](/submissions/MI/subpart-b%E2%80%94diagnostic-devices/LON) · K031943 # BD PHOENIX AUTOMATED MICROBIOLOGY SYSTEM - CEPHALOTHIN (GN) 1-64 UG/ML (K031943) _Becton, Dickinson & CO · LON · Aug 6, 2003 · Microbiology · SESE_ **Canonical URL:** https://fda.innolitics.com/submissions/MI/subpart-b%E2%80%94diagnostic-devices/LON/K031943 ## Device Facts - **Applicant:** Becton, Dickinson & CO - **Product Code:** [LON](/submissions/MI/subpart-b%E2%80%94diagnostic-devices/LON.md) - **Decision Date:** Aug 6, 2003 - **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 BD Phoenix™ system performs automated antimicrobial susceptibility testing (AST) and identification (ID). System utilizes sealed, self-inoculating polystyrene trays with 136 micro-wells containing dried reagents. Pure culture colonies are suspended in broth, equated to 0.5 McFarland standard using a nephelometer, and diluted into AST broth containing a redox indicator. Inoculated panels are barcode-scanned and incubated at 35°C. Instrument continuously monitors colorimetric oxidation-reduction of the indicator; growth in the presence of antibiotics prevents indicator reduction, while inhibited organisms do not cause color change. Readings occur every 20 minutes. Software-driven 'EXPERT' system interprets biochemical and AST results based on NCCLS rules to provide MIC values and categorical interpretations. System is used in clinical microbiology laboratories; results assist clinicians in selecting appropriate antimicrobial therapy. ## Clinical Evidence Performance evaluated against NCCLS reference broth microdilution method using clinical, stock, and challenge isolates. Study included multi-site reproducibility testing (intra-site >90%, inter-site >95%). Clinical performance for cephalothin (1-64 µg/mL) on Gram-negative panels showed 95.9% Essential Agreement (n=1206) and 82.8% Category Agreement (n=1206). ## Technological Characteristics Automated microbiology system; molded polystyrene panels with 136 micro-wells; broth microdilution method; redox indicator for growth detection; turbidity measurement; 35°C incubation; automated optical reading every 20 minutes; software-based interpretation of MIC and categorical results. ## 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 DEVICE ONLY TEMPLATE A. 510(k) Number: k031943 B. Analyte: Cephalothin 1-64 µg/mL Gram-negative AST C. Type of Test: Antimicrobial Susceptibility Test (Quantitative) colorimetric oxidation-reduction, growth-based D. Applicant: Becton Dickinson & Company E. Proprietary and Established Names: BD Phoenix™ Automated Microbiology System – Cephalothin 1 – 64 µg/mL F. Regulatory Information: 1. Regulation section: 21 CFR 866.1645 Fully Automated Short-Term Incubation Cycle Antimicrobial 2. Classification: Class II 3. Product Code: LON 4. Panel: 83 G. Intended Use: 1. Intended use(s): BD Phoenix™ Automated Microbiology System: The BD Phoenix™ Automated Microbiology System is intended for in vitro quantitative determination of antimicrobial susceptibility by minimal inhibitory concentration of gram-negative aerobic and facultative anaerobic bacteria belonging to the family Enterobacteriaceae and non-Enterobacteriaceae and gram-positive bacteria belonging to the genera Staphylococcus and Enterococcus. The BD Phoenix™ GN Panel: The BD Phoenix™ Automated Microbiology System is intended for the in vitro rapid identification (ID) and 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. 2. Indication(s) for use: {1} Page 2 of 5 This submission is for the addition of the antibiotic cephalothin at concentrations of $1 - 64~\mu \mathrm{g / mL}$ to the gram negative susceptibility panel. 3. Special condition for use statement(s): The BD Phoenix™ expert rules follow NCCLS recommendations. Literature search (Sanford Guide to Antimicrobial Therapy) support’s the applicant’s claim to report out the following organisms namely, *Citrobacter koseri*, *Escherichia coli*, *Klebsiella oxytoca*, *Klebsiella pneumoniae* and *Proteus mirabilis*. Cefazolin, cefuroxime, cefpodoxime, cefprozil, and loracarbef (urinary isolates only) may be tested individually, because some isolates may be susceptible to these agents when resistant to cephalothin. 4. Special instrument Requirements: H. Device Description: The BD Phoenix™ 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 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 broth, which contains an AST indicator, prior to inoculating the panel. The AST broth is a cation-adjusted formulation of Mueller-Hinton broth containing $0.01\%$ Tween 80. After adding the indicator solution to the AST inoculum the color is blue and after inoculation and incubation goes to pink to 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 $35^{\circ}\mathrm{C}$. The AST has a final inoculum of $5 \times 10^{5}$ 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 NCCLS documentation. 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. I. Substantial Equivalence Information: 1. Predicate device name(s): VITEK® System 2. Predicate K number(s): {2} Page 3 of 5 N50510 3. Comparison with predicate: | Similarities | | | | --- | --- | --- | | Item | Device | Predicate | | 1. | Isolated colonies from culture used | Isolated colonies from culture used | | 2. | Inoculum density equated to 0.5 McFarland standard | Inoculum density equated to 0.5 McFarland standard | | 3. | Results are determined from serial twofold dilutions of antimicrobial agents | Results are determined from serial twofold dilutions of antimicrobial agents | | 4. | Report results as minimum inhibitory concentration (MIC) and categorical interpretation (SIR) | Report results as minimum inhibitory concentration (MIC) and categorical interpretation (SIR) | | 5. | <16 hours | <16 hours | | Differences | | | | Item | Device | Predicate | | 1. | 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. | J. Standard/Guidance Document Referenced (if applicable): “Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA” K. 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™ 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 contain no antibiotic. L. Performance Characteristics (if/when applicable): 1. Analytical performance: a. Precision/Reproducibility: Reproducibility within sites was determined using the QC isolates for >95% reproducibility. Between sites was performed at three sites for >95% reproducibility on seven isolates. Reproducibility studies conducted used the 10 isolate study design as recommended in the {3} Page 4 of 5 "Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA." The QC isolate was used to augment this study to provide additional on-scale results. b. Linearity/assay reportable range: Not applicable c. Traceability (controls, calibrators, or method): The recommended QC isolate was tested a sufficient number of times with acceptable results with the reference method. The Phoenix results demonstrate that the system can produce QC results in the recommended range. | ORGANISM | conc. | Reference | | | Phoenix | | | | --- | --- | --- | --- | --- | --- | --- | --- | | | | | | | | | | | E. coli ATCC 25922 Expected range: 4 – 16 μg.mL | 2 | | | | | 1 | | | | 4 | | | | | | | | | 8 | | 15 | | | 373 | | | | 16 | | 343 | | | 10 | | | | 32 | | 24 | | | 1 | | | | 64 | | 1 | | | | | | | >64 | | 1 | | | 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. 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 NCCLS recommended broth dilution reference panel was prepared according to the NCCLS recommendation. Clinical testing {4} was performed at six sites. 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 >99%. A comparison was provided to the reference method with the following agreement. | | EA Tot | EA N | EA % | Eval EA Tot | Eval EA N | Eval EA % | CA N | CA % | #R | min | maj | vmj | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | Clinical | 1152 | 1104 | 95.8 | 855 | 822 | 96.1 | 949 | 82.4 | 420 | 189 | 4 | 10 | | Challenge | 51 | 49 | 96.2 | 19 | 18 | 94.7 | 47 | 92.3 | 34 | 3 | 1 | 0 | | Combined | 1203 | 1153 | 95.9 | 874 | 840 | 96.1 | 996 | 82.8 | 454 | 192 | 5 | 10 | EA-Essential Agreement CA-Category Agreement R-resistant isolates maj-major discrepancies vmj-very major discrepancies min-minor discrepancies 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. The lower than expected CA can be attributed to the large number of results around the interpretative cut-off as reflected in the good EA of evaluable. These are minor errors that are +/- one well of the reference method. 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): 4. Clinical cut-off: Not applicable 5. Expected values/Reference range: $\leq 8(\mathrm{S}), 16(\mathrm{I}), \geq 32(\mathrm{R})$ The expected value range, interpretative criteria and QC are the same as recommended in NCCLS. All values will be included in the package insert. M. Conclusion: This demonstrates acceptable performance as described in the FDA guidance document, "Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA" and therefore the testing of cephalothin on the BD Phoenix™ Automated Microbiology AST System is substantially equivalent to other commercial devices such as bioMerieux Vitek® AST panels. --- **Source:** [https://fda.innolitics.com/submissions/MI/subpart-b%E2%80%94diagnostic-devices/LON/K031943](https://fda.innolitics.com/submissions/MI/subpart-b%E2%80%94diagnostic-devices/LON/K031943) **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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