MICROSCAN MICROSTREP PLUS PANEL CEFEPIME (O.015 - 8 MCG/ML)

{0} Page 1 of 7 # 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY ASSAY ONLY TEMPLATE A. 510(k) Number: K063099 B. Purpose for Submission: To add the option for automated reading of Cefepime at 0.015 – 8 µg/mL to the MICroSTREP plus® Panel on the MicroScan® WalkAway System C. Measurand: Cefepime at 0.015 – 8 µg/mL D. Type of Test: Quantitative and Qualitative growth based detection algorithm using optics light detection E. Applicant: Dade Behring Inc, MicroScan® F. Proprietary and Established Names: MicroScan® MICroSTREP plus® Panel – Cefepime at 0.015 – 8 µg/mL G. Regulatory Information: 1. Regulation section: 21 CFR 866.1640 – Antimicrobial Susceptibility Test Powder 2. Classification: Class II 3. Product Code: LRG – Instrument for Auto Reader & Interpretation of Overnight Antimicrobial Susceptibility System LTT – Panels, Test, Susceptibility, Antimicrobial 4. Panel: 83 Microbiology H. Intended Use: 1. Intended use(s): Cefepime at 0.015 – 8 µg/mL is for use with MICroSTREP plus® Panels. MICroSTREP plus® Panels are designed for use in determining quantitative {1} Page 2 of 7 and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of aerobic streptococci, including *Streptococcus pneumoniae*. 2. **Indication(s) for use:** This submission is for adding the option for automated reading of the Cefepime at concentrations of 0.015 – 8 µg/mL to MICroSTREP *plus®* Panels on the MicroScan® WalkAway System for testing *Streptococcus pneumoniae*, *Streptococcus pyogenes*, *Streptococcus agalactiae*, and viridans group streptococci. 3. **Special condition for use statement(s):** Prescription Use Only Turbidity method of inoculum preparation only The absence of resistant strains of beta hemolytic streptococci precludes defining any results categories other than “susceptible”. For isolates yielding results suggestive of a “nonsusceptible” category, organism identification and antimicrobial susceptibility results should be confirmed. 4. **Special instrument Requirements:** Not Applicable I. **Device Description:** The MicroScan® MICroSTREP *plus®* Panel is a 96-well plastic dish which contains microdilutions of each antimicrobic in various concentrations dried in aqueous solutions. The panel is rehydrated and inoculated at the same time with a Mueller-Hinton broth supplemented with lysed horse blood (2 – 5%). The target inoculum concentration for each well should be approximately 5 × 10⁵ colony forming units (CFU)/mL. Panels are incubated in a 35°C non-CO₂ incubator for 20-24 hours. After incubation, the panels are read manually for growth. Additionally, panels may be incubated in and read by a MicroScan® WalkAway instrument. Each panel contains a “growth” but it does not contain a “no growth” control well. J. **Substantial Equivalence Information:** 1. **Predicate device name(s):** MICroSTREP *plus®* 2. **Predicate K number(s):** K021188 3. **Comparison with predicate:** {2} | Similarities | | | | | --- | --- | --- | --- | | Item | Device | | Predicate | | Intended use | Determination of susceptibility to antimicrobials with aerobic streptococci including Streptococcus pneumoniae | | Same | | Isolates | For use with aerobic streptococci including Streptococcus pneumoniae isolated colonies from culture | | Same | | Results | Quantitative with qualitative interpretations | | Same | | Incubation | 20 – 24 hours | | Same | | Panels | Cefepime dried in aqueous solution | | Same | | Differences | | | | | Item | Device | | Predicate | | Technology | Growth based using algorithm with optics light detection | | Growth based | | Reading | Overnight method Manual or automated | | Overnight method Manual read only | | Instrument | MicroScan® WalkAway System or Microdilution viewer | | Microdilution viewer | # K. Standard/Guidance Document Referenced (if applicable): "Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA"; CLSI M7 (M100-S16) "Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically; Approved Standard." # L. Test Principle: The antimicrobial susceptibility tests are miniaturizations of the broth dilution susceptibility test that have been diluted in water and dehydrated. Various antimicrobial agents are diluted in water, buffer or minute concentrations of broth to concentrations bridging the range of clinical interest. Panels are rehydrated with $115~\mu \mathrm{L}$ Mueller-Hinton broth supplemented with $2 - 5\%$ lysed horse blood (LHB), after inoculation of the broth with a standardized suspension of the organism. The target inoculum concentration for each well should be approximately $5\times 10^{5}$ colony forming units (CFU)/mL. After incubation in a non- $\mathrm{CO}_{2}$ incubator for 20-24 hours, the minimum inhibitory concentration (MIC) for the test organisms is determined by observing the lowest antimicrobial concentration showing inhibition of growth. Panels can be read manually using indirect light or the panels can be read on the MicroScan® WalkAway instrument using optics light detection. {3} Page 4 of 7 ## M. Performance Characteristics (if/when applicable): This submission is for the AST Panel only. The ID System was not reviewed. The Reproducibility studies, QC performance data, and Challenge isolates evaluated by the manual and automated reading methods are required to demonstrate that there is no difference between manual reading and automated reading in the MicroScan® WalkAway System. The clinical efficacy performance was previously established using the manual read method and was therefore not required for this submission. ## 1. Analytical performance: a. **Precision/Reproducibility:** Reproducibility was demonstrated using 10 isolates tested at 4 sites on 3 separate days in triplicate, for a total of 360 results. The study included testing on the MicroScan® WalkAway System with automated reading at 20-24 hours, and manual readings at 20-24 hours incubation. Both reading methods demonstrated >95% reproducibility, and no differences were observed. b. **Linearity/assay reportable range:** Not applicable c. **Traceability, Stability, Expected values (controls, calibrators, or method):** The recommended QC isolate *S. pneumoniae* ATCC 49619 was tested a sufficient number of times with acceptable results on all testing days with the reference method. Quality control results demonstrated the ability of the different reading parameters (manual and instrument) to produce acceptable results on >95% of the testing days. The following table provides the frequency of results in each concentration with the expected range stated. Both reading methods produced the same mode, which was slightly more resistant than the mode for the reference method, if only by one dilution. {4} Page 5 of 7 | Organism | Concentration μg/mL | Reference results | MicroScan® WalkAway results | | | --- | --- | --- | --- | --- | | | | | Manual Overnight | Instrument Overnight | | S. pneumoniae ATCC 49619 Expected range 0.03—0.25 μg/mL | ≤ 0.015 | | | | | | 0.03 | | 1 | 2 | | | 0.06 | 78 | 15 | 24 | | | 0.12 | 5 | 70 | 62 | | | 0.25 | | 3 | | | | 0.5 | | | 1 | | | 1 | | | | Inoculum density control: A turbidity meter, which was verified each day of testing, was used for the turbidity inoculation method. Colony counts were performed weekly, on the ATCC S. pneumoniae with all results in the expected range of approximately $5 \times 10^{5}$. No trending was observed. 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: Clinical efficacy testing with manual result reading was conducted in the previous submission (K021188). In this submission, Challenge isolates were evaluated by the manual and automated reading methods to demonstrate that there is no difference between manual reading and instrument reading on the MicroScan® WalkAway System. There were 70 challenge isolates including 53 Streptococcus pneumoniae CDC Challenge Set strains, tested at one internal site and compared to the reference broth dilution result, which was obtained prior to the design validation. A comparison was done with readings on the instrument after 20 hours incubation, and also read manually when incubated for 20-24 hours. Performance by the automated reading method was acceptable with no differences or trends. The recommended CLSI reference method was followed with the exception of the use of a small amount (0.1%) of Pluronic (a wetting agent) in the final inoculum. A validation of the use of Pluronic in the {5} Page 6 of 7 frozen reference panel was conducted. QC was also performed with no difference apparent in the results. Read method comparison of Streptococcus species and Cefepime | | EA Tot | EA N | EA % | Eval EA Tot | Eval EA N | Eval EA % | #R | min | maj | vmj | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | Challenge Manual | 70 | 66 | 94.3 | 60 | 57 | 95.0 | 2 | 11 | 0 | 0 | | Challenge Automated | 70 | 67 | 95.7 | 60 | 58 | 96.7 | 2 | 10 | 0 | 0 | EA-Essential Agreement R-resistant isolates maj-major discrepancies vmj-very major discrepancies min- minor discrepancies Essential agreement (EA) is when the Microscan® MICroSTREP plus® panels agree with the reference test panel results exactly or within one doubling dilution of the reference method. Evaluable (Eval) are results that are within the test range and on scale. Automated reading results were the same as the manual reading results with no trending. There were no vmj, no maj, and there was 1 additional minor error generated only by the manual reading method. The overall EA% of 94.3% and Eval EA% of 95.0% for the manual read and overall EA% of 95.6% and Eval EA% of 96.7% for the automated reading were both very good. The test device had a growth rate of >95% for both the manual reading and the automated reading methods. The comparison of the reading methods demonstrates that the manual reading method and the automated reading on the MicroScan® WalkAway System are no different. The efficacy data performed with the manual reading method would therefore be expected to have no differences. The performance data currently documented in the package insert will not change. b. Matrix comparison: Not applicable 3. Clinical studies: a. Clinical sensitivity: Not applicable b. Clinical specificity: Not applicable {6} Page 7 of 7 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: Interpretive criteria | Cefepime | S | I | R | | --- | --- | --- | --- | | Streptococcus pneumoniae | ≤ 1 | 2 | ≥ 4 | | Beta hemolytic streptococci group* | ≤ 0.5 | --- | --- | | Viridans streptococci group | ≤ 1 | 2 | ≥ 4 | The expected value range, interpretive criteria and QC as recommended by CLSI are included in the package insert. *The absence of resistant strains of beta hemolytic streptococci precludes defining any results categories other than “susceptible”. For isolates yielding results suggestive of a “nonsusceptible” category, organism identification and antimicrobial susceptibility results should be confirmed. N. Proposed Labeling: The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10. O. Conclusion: The submitted information in this premarket notification is complete and supports a substantial equivalence decision.