MicroScan Dried Gram Negative MIC/Combo Panels with Ciprofloxacin (Cp) (0.004 - 8µg/mL)

{0} FDA U.S. FOOD & DRUG ADMINISTRATION # 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY ASSAY ONLY ## I Background Information: A 510(k) Number K193536 B Applicant Beckman Coulter, Inc C Proprietary and Established Names MicroScan Dried Gram Negative MIC/Combo Panels with Ciprofloxacin (Cp) (0.004 - 8 µg/mL) D Regulatory Information | Product Code(s) | Classification | Regulation Section | Panel | | --- | --- | --- | --- | | LTT, JWY, LRG, LTW | Class II | 21 CFR 866.1640 - Antimicrobial Susceptibility Test Powder | MI - Microbiology | ## II Submission/Device Overview: A Purpose for Submission: To obtain a substantial equivalence determination for ciprofloxacin at concentrations of 0.004 – 8 µg/mL with the MicroScan Dried Gram-Negative MIC/Combo Panels for susceptibility testing of non-fastidious gram negative organisms. B Measurand: Ciprofloxacin in the dilution range of 0.004 – 8 µg/mL C Type of Test: Quantitative antimicrobial susceptibility test (AST) Food and Drug Administration 10903 New Hampshire Avenue Silver Spring, MD 20993-0002 {1} K193536 - Page 2 of 16 # III Intended Use/Indications for Use: ## A Intended Use(s): MicroScan Dried Gram Negative MIC/Combo Panels are designed for use in determining quantitative and/or qualitative antimicrobial susceptibility of colonies grown on solid media of rapidly growing aerobic and facultative gram-negative bacilli. ## B Indication(s) for Use: The MicroScan Dried Gram Negative MIC/Combo Panel is used to determine quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of rapidly growing aerobic and facultative anaerobic gram-negative bacilli. After inoculation, panels are incubated for 16-20 hours at 35 degrees C +/- 1 degree centigrade in a non-CO₂ incubator, and read either visually or with MicroScan instrumentation, according to the Package Insert. This particular submission is for updated susceptibility test interpretive criteria for Enterobacteriaceae and Pseudomonas aeruginosa, as well as expanding Salmonella ser. Typhi interpretive criteria to all Salmonella spp. for the antimicrobial ciprofloxacin (Cp) at concentrations of 0.004 to 8 ug/mL to the test panel. Ciprofloxacin 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: - Citrobacter koseri - Citrobacter freundii - Enterobacter cloacae - Escherichia coli - Klebsiella pneumoniae - Morganella morganii - Proteus mirabilis - Providencia rettgeri - Providencia stuartii - Pseudomonas aeruginosa - Salmonella ser. Typhi - Serratia marcescens - Shigella flexneri - Shigella sonnei Active in vitro but clinical significance is unknown: - Enterobacter aerogenes - Klebsiella oxytoca - Salmonella enteritidis ## C Special Conditions for Use Statement(s): Rx - For Prescription Use Only {2} The ability of the MicroScan Dried Gram Negative Panels to detect resistance to ciprofloxacin is unknown for the following species because an insufficient number of resistant strains were available at the time of comparative testing: C. koseri, P vulgaris, Shigella sonnei and Salmonella enteritidis. Isolates yielding MIC results suggestive of a resistant interpretive category should be submitted to a reference laboratory. Results obtained with ciprofloxacin and E. cloacae with all read methods/Prompt, E. aerogenes with WalkAway/Prompt and manual/Prompt, S. sonnei with manual/Prompt and S. marcescens with the autoSCAN-4/Prompt and manual/Prompt have shown discrepant MICs when compared with the reference method. If critical to patient care, isolates of those species should be retested using the turbidity inoculation method. In addition, discrepant MICs were observed with ciprofloxacin and C. koseri with turbidity/manual read; if critical to patient care, isolates of C. koseri should be tested with an alternate inoculation/read method. Due to low categorical agreement and increased occurrence of very major errors for P. aeruginosa and ciprofloxacin with the autoSCAN-4 and Prompt inoculation, results should be confirmed by manual read prior to reporting. ## D Special Instrument Requirements: MicroScan panels can be read either manually or automatically on the WalkAway or autoScan-4 instrument systems. ## IV Device/System Characteristics: ### A Device Description: The MicroScan Dried Gram-Negative MIC/Combo panel with ciprofloxacin is used to determine the quantitative and/or qualitative antimicrobial agent susceptibility of aerobic and facultatively anaerobic gram-negative bacilli colonies grown on solid media. After inoculation, panels are incubated for 16-20 hours at $35^{\circ}\mathrm{C} \pm 1^{\circ}$ in a non- $\mathrm{CO}_{2}$ incubator and read either visually or with MicroScan instrumentation according to the package insert. Inoculation methods: Turbidity or Prompt Inoculation System Read methods: Manual, MicroScan WalkAway System and MicroScan autoSCAN-4 ### B Principle of Operation: The antimicrobial susceptibility tests are dehydrated miniaturizations of the broth dilution susceptibility test. Various antimicrobial agents are diluted in Mueller Hinton broth supplemented with calcium and magnesium to concentrations spanning the range of clinical interest. Breakpoint Combo panels use concentrations equivalent to the categorical breakpoints determined or recognized by FDA. After inoculation and rehydration with a standardized suspension of organism and incubation at $35^{\circ}\mathrm{C}$ for a minimum of 16 hours, the minimum inhibitory concentration (MIC) for the test organism is determined by observing the lowest antimicrobial concentration showing inhibition of growth. K193536 - Page 3 of 16 {3} # V Substantial Equivalence Information: A Predicate Device Name(s): MicroScan Dried Gram Negative MIC/Combo Panels with Meropenem (Mer) $(0.004 - 32\mu \mathrm{g / mL})$ B Predicate 510(k) Number(s): K192355 C Comparison with Predicate(s): Table 1. Comparison with Predicate | Device & Predicate Device(s): | Device: K193536 | Predicate: K192355 | | --- | --- | --- | | Device Trade Name | MicroScan Dried Gram Negative MIC/Combo Panels - Ciprofloxacin | MicroScan Dried Gram Negative MIC/Combo Panels - Meropenem | | General Device Characteristic Similarities | | | | Intended Use/Indications For Use | Determination of susceptibility with gram-negative bacilli | Same | | Technology | Overnight microdilution MIC susceptibility test | Same | | Specimen | Isolated colonies from culture | Same | | Incubation Temperature | 35 °C ± 1°C | Same | | Incubation Atmosphere | Aerobic | Same | | Incubation Time | 16-20 hours | Same | | Reading Method | Automated (WalkAway or autoSCAN-4) or Manual | Same | | Result Reported | Report results as minimum inhibitory concentration (MIC) and categorical interpretation (SIR) | Same | | General Device Characteristic Differences | | | | Antimicrobial Agent | Dried Ciprofloxacin 0.004 – 8 μg/mL | Dried Meropenem 0.004 – 32 μg/mL | K193536 - Page 4 of 16 {4} VI Standards/Guidance Documents Referenced: 1. Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA 2. CLSI M07-A10. Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically. 10th ed. (January 2015) 3. CLSI M100. Performance Standards for Antimicrobial Susceptibility Testing. 29th ed. (January 2019) VII Performance Characteristics (if/when applicable): A Analytical Performance: 1. Precision/Reproducibility: A reproducibility study was conducted at three external sites using 12 isolates of gram-negative bacilli that were consistent with the intended use. The range of ciprofloxacin dilutions tested was 0.004-8 µg/mL. Isolates were tested in triplicate over three days for a total of 324 data points (27 data points per isolate). The isolates tested in the reproducibility study included: C. freundii complex (1 isolate), C. koseri (1 isolate), E. cloacae (1 isolate), E. coli (2 isolates), K. oxytoca (2 isolates), K. pneumoniae (2 isolates), S. marcescens (1 isolate), Salmonella ser. Typhi (1 isolate) and P. aeruginosa (1 isolate). Inocula were prepared using both the turbidity and Prompt methods and results were read manually (visually) and with the WalkAway and autoSCAN-4 instrument systems. The majority of data points were within ± one doubling dilution of the mode MIC value. The data was analyzed as described in the Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems. Because results from all sites were all on-scale, only a single combined reproducibility result is reported for each read method. The reproducibility results are acceptable and are shown in Table 2 below. Table 2. Reproducibility of Ciprofloxacin with all Inoculation and Read Methods | Read Method | Reproducibility No. within ±dilution of the mode MIC value (%) | | | --- | --- | --- | | | Prompt Inoculation | Turbidity Inoculation | | WalkAway | 318/324 (98.1) | 323/324 (99.7) | | autoSCAN-4 | 315/324 (97.2) | 319/324 (98.5) | | Manual | 318/324 (98.1) | 322/324 (99.4) | 2. Linearity: Not applicable 3. Analytical Specificity/Interference: Not applicable K193536 - Page 5 of 16 {5} 4. Assay Reportable Range: Not applicable 5. Traceability, Stability, Expected Values (Controls, Calibrators, or Methods): Inoculum Density Check. A spectrophotometric device, the MicroScan Turbidity Meter, was used to ensure the accuracy of the turbidity inoculation method. A zero check of the turbidity meter was performed daily. The inocula prepared using the turbidity method were standardized using a reading of 0.08 ± 0.02 (equivalent to a 0.5 McFarland barium sulfate turbidity standard). The digital reading was recorded for each isolate and was considered acceptable based on recommendations in the Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems. Inoculum density colony counts were evaluated from suspensions of the QC strain E. coli ATCC 25922 and were found to be within the acceptable concentration range as recommended in the CLSI document M07, Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically. Inoculum density data for the Prompt inoculation system was collected from suspensions of the QC strain E. coli ATCC 25922 and for all reproducibility isolates. The overall average colony count was within the acceptable range for all isolates. Purity Check. Purity checks were performed on all isolates for each inoculum preparation; only results from pure cultures were included. Growth Failure Rate. All organisms evaluated showed growth on the dried test panels. Quality Control Testing. The CLSI-recommended QC organisms E. coli ATCC 25922 and P. aeruginosa ATCC 27853 were tested with all inoculation and read methods using 12 dilutions of ciprofloxacin (0.004 – 8 µg/mL). The reference panel was inoculated using the turbidity method only. In this submission the QC range for both E. coli ATCC 25922 and P. aeruginosa ATCC 27853 reflect the current MIC ranges recommended in the CLSI document M100, Performance Standards for Antimicrobial Susceptibility Testing 29th ed. For both QC strains, quality control results were within the acceptable range for all inoculation and read methods. Results of current QC testing are shown in Table 3 below and demonstrate that acceptable QC results can be obtained with this device for >95% of tests. K193536 - Page 6 of 16 {6} Table 3. Quality Control Results for all Inoculation and Read Methods for Ciprofloxacin | Organism | Conc. (μg/mL) | Reference | Prompt Inoculation Method | | | Turbidity Inoculation Method | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | | | | | Manual | WalkAway | AS4 | Manual | WalkAway | AS4 | | E. coli ATCC 25922 Expected Range 0.004-0.016 μg/mL | ≤0.004 | 2 | | | | | | | | | 0.008 | 175 | 66 | 40 | 149 | 40 | 13 | 131 | | | 0.016 | 12 | 122 | 144 | 38 | 148 | 175 | 57 | | | 0.03 | | | 1 | | | | | | | 0.06 | | | | | 1 | 1 | | | | 0.12 | | | | | | | | | | 0.25 | | 1 | 1 | 1 | | | | | | 0.5 | | | | | | | | | | 1 | | | | | | | | | | 2 | | | | | | | | | | 4 | | | | | | | | | | 8 | | | | | | | | | | | | | | | | | | | P. aeruginosa ATCC 27853 Expected Range 0.12 - 1.0 μg/mL | ≤0.004 | | | | | | | | | | 0.008 | | | | | | | | | | 0.016 | | | | | | | | | | 0.03 | | | | | | | | | | 0.06 | | | | | | | | | | 0.12 | | | | | | | | | | 0.25 | 131 | 63 | 41 | 123 | 171 | 175 | 183 | | | 0.5 | 58 | 124 | 141 | 66 | 18 | 14 | 4 | | | 1 | | 2 | 3 | | | | | | | 2 | | | | | | | | | | 4 | | | | | | | | | | 8 | | | | | | | | 6. Detection Limit: Not Applicable 7. Assay Cut-Off: Not Applicable B Comparison Studies: 1. Method Comparison with Predicate Device: The results obtained with the MicroScan Dried Gram-Negative MIC/Combo Panel with ciprofloxacin (dilution range 0.004 – 8 μg/mL) were compared to results obtained using a frozen broth microdilution reference panel (dilution range 0.004 – 8 μg/mL). Clinical isolates were evaluated at three testing sites in the U.S. in a single study; challenge isolates were evaluated in two separate studies performed at internal and external sites. The reference panel was prepared as described in CLSI document M07-A10 except for the use of Pluronic-F in the inoculum water for the reference panel. A validation study was K193536 - Page 7 of 16 {7} performed to demonstrate the equivalence between reference panels inoculated with organisms suspended in water supplemented with Pluronic-F and reference panels inoculated with autoclaved deionized water without Pluronic-F as part of studies performed for K172912, MicroScan Dried Gram-Negative MIC/Combo Panels with Ciprofloxacin-S (0.004-8 µg/mL). The effect of Pluronic-F in the reference panel was determined with 11 Salmonella ser. Typhi isolates; performance was determined to be acceptable For the reference method and MicroScan panels inoculated using the turbidity method, panels were inoculated using the same standardized suspension further diluted into 25 mL of water with Pluronic-D (for the MicroScan panels) or Pluronic-F (for the frozen reference panels). MicroScan panels were also inoculated using the Prompt inoculation method with isolates inoculated into the Prompt inoculation bottle. Reference panels were read manually (visually); MicroScan panels inoculated with both inoculation methods were read using the WalkAway and autoSCAN-4 instruments and by manual read. ## Clinical Isolates To determine the performance of the MicroScan Dried Gram-Negative MIC/Combo Panel with Ciprofloxacin, a total of 604 non-Salmonella Enterobacteriaceae clinical isolates were evaluated with all inoculation and read methods at three sites; 543 of the isolates were from indicated species which included the following: C. freundii (12 isolates), C. koseri (49 isolates), K. aerogenes (32 isolates), E. cloacae (48 isolates), E. coli (77 isolates), K. oxytoca (47 isolates), K. pneumoniae (89 isolates), M. morganii (41 isolates), P. mirabilis (56 isolates), P. vulgaris (17 isolates), P. rettgeri (19 isolates), P. stuartii (21 isolates), S. marcescens (32 isolates), S. flexneri (1 isolate), and S. sonnei (2 isolates). An additional 61 isolates of non-indicated Enterobacteriaceae isolates (approximately 10% of the total number of isolates tested) were also evaluated. The addition of the non-indicated species impacted but did not improve the performance calculated using indicated species alone. A total of 19 clinical isolates of Salmonella spp. were evaluated including S. enteritidis (6 isolates), and Salmonella spp. (13 isolates). A total of 79 clinical isolates of P. aeruginosa were evaluated with an appropriate mix of fresh isolates and recent isolates. The clinical isolates evaluated represented an appropriate mix of fresh isolates (tested within one week of isolation), recent isolates (tested within six months of isolation with minimal subculturing and stock isolates (tested at any time after isolation). ## Challenge isolates A total of 85 Enterobacteriaceae challenge isolates were evaluated at one site. These included: C. koseri, K. aerogenes, E. cloacae, E. coli, K. oxytoca, K. pneumoniae, M. morganii, P. mirabilis, P. rettgeri, S. marcescens, S. flexneri, S. sonnei and 5 isolates of non-indicated species. In addition, two Salmonella ser. Typhi and 14 P. aeruginosa challenge isolates were evaluated. A single isolate of S. flexneri was excluded from the analysis of performance of the WalkAway read method due to the lack of results for this method. Results for EA, CA and categorical errors for Enterobacteriaceae, Salmonella spp. and P. aeruginosa for all inoculation and read methods are shown in Tables 4 and 5 below. Overall K193536 - Page 8 of 16 {8} results for Enterobacteriaceae, Salmonella spp. and $P_{\cdot}$ aeruginosa with all inoculation and read methods were acceptable. Salmonella spp. results were evaluated separately from Enterobacteriaceae due to differences in susceptibility test interpretive criteria. In addition to the 21 clinical and challenge isolates of Salmonella spp. that were tested in this study, the previously cleared submission, K172912 was referenced to expand the evaluation of the performance of ciprofloxacin with Salmonella spp. Performance obtained with 74 isolates of Salmonella ser. Typhi evaluated with ciprofloxacin in K172912 (100% EA and CA for all inoculation and read methods) were considered in the evaluation of ciprofloxacin performance with members of this genus. The overall EA and CA performance for Salmonella spp. tested in the current study was acceptable for each inoculation and read method (Tables 4 and 5) and there were no major or very major errors. Based on the acceptable performance of ciprofloxacin for Salmonella species in these two submissions, the following previously imposed limitation (in K172912) was removed from the labeling associated with the current submission: Ciprofloxacin labeled as Cp-S is not indicated for use for any species other than Salmonella Typhi. Table 4. Performance of MicroScan Dried Gram-Negative Panels with Ciprofloxacin, Using Prompt Inoculation and all Read Methods | | Tot | No. EA | EA % | Eval EA Tot | No. Eval EA | Eval EA % | No. CA | CA % | No. R | No. S | mi n | maj | Vmj | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | WalkAway Read | | | | | | | | | | | | | | | Enterobacteriaceae - Breakpoints ≤0.25, 0.5, ≥1 μg/mL | | | | | | | | | | | | | | | Clinical | 604 | 565 | 93.5 | 515 | 480 | 93.2 | 592 | 98.0 | 116 | 483 | 12 | 0 | 0 | | Challenge | 84a | 81 | 96.4 | 60 | 57 | 95.0 | 82 | 97.6 | 30 | 51 | 2 | 0 | 0 | | Combined | 688 | 646 | 93.9 | 575 | 537 | 93.4 | 674 | 98.0 | 146 | 534 | 14 | 0 | 0 | | Salmonella spp. - Breakpoints ≤0.06, 0.12 - 0.5, ≥1 μg/mL | | | | | | | | | | | | | | | Clinical | 19 | 19 | 100 | 19 | 19 | 100 | 19 | 100 | 0 | 17 | 0 | 0 | 0 | | Challenge | 2 | 2 | 100 | 1 | 1 | 100 | 1 | 50.0 | 1 | 1 | 1 | 0 | 0 | | Combined | 21 | 21 | 100 | 20 | 20 | 100 | 20 | 95.2 | 1 | 18 | 0 | 0 | 0 | | P. aeruginosa - Breakpoints ≤0.5, 1, ≥2 μg/mL | | | | | | | | | | | | | | | Clinical | 79 | 77 | 97.5 | 70 | 68 | 97.1 | 74 | 93.7 | 23 | 54 | 4 | 1 | 0 | | Challenge | 14 | 13 | 92.9 | 13 | 12 | 92.3 | 11 | 78.6 | 6 | 4 | 3 | 0 | 0 | | Combined | 93 | 90 | 96.8 | 83 | 80 | 96.4 | 85 | 91.4 | 29 | 58 | 7 | 1 | 0 | | | | | | | | | | | | | | | | | autoSCAN-4 Read | | | | | | | | | | | | | | | Enterobacteriaceae - Breakpoints ≤0.25, 0.5, ≥1 μg/mL | | | | | | | | | | | | | | | Clinical | 604 | 568 | 94.0 | 515 | 482 | 93.6 | 593 | 98.2 | 116 | 483 | 11 | 0 | 0 | | Challenge | 85 | 81 | 95.3 | 63 | 59 | 93.6 | 81 | 95.3 | 30 | 52 | 4 | 0 | 0 | | Combined | 689 | 649 | 94.2 | 578 | 541 | 93.6 | 674 | 97.8 | 146 | 535 | 15 | 0 | 0 | | Salmonella spp. - Breakpoints ≤0.06, 0.12 - 0.5, ≥1 μg/mL | | | | | | | | | | | | | | | Clinical | 19 | 19 | 100 | 19 | 19 | 100 | 19 | 100 | 0 | 17 | 0 | 0 | 0 | | Challenge | 2 | 2 | 100 | 1 | 1 | 100 | 2 | 100 | 1 | 1 | 0 | 0 | 0 | | Combined | 21 | 21 | 100 | 20 | 20 | 100 | 21 | 100 | 1 | 18 | 0 | 0 | 0 | | P. aeruginosa - Breakpoints ≤0.5, 1, ≥2 μg/mL | | | | | | | | | | | | | | | Clinical | 79 | 74 | 93.7 | 70 | 65 | 92.9 | 68 | 86.1 | 23 | 54 | 9 | 1 | 1 | | Challenge | 14 | 13 | 92.9 | 14 | 13 | 92.9 | 10 | 71.4 | 6 | 4 | 3 | 0 | 1 | | Combined | 93 | 87 | 93.5 | 84 | 78 | 92.9 | 78 | 83.9 | 29 | 58 | 12 | 1 | 2 | K193536 - Page 9 of 16 {9} | | Tot | No. EA | EA % | Eval EA Tot | No. Eval EA | Eval EA % | No. CA | CA % | No. R | No. S | mi n | maj | Vmj | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | Manual Read | | | | | | | | | | | | | | | Enterobacteriaceae – Breakpoints ≤0.25, 0.5, ≥1 μg/mL | | | | | | | | | | | | | | | Clinical | 604 | 565 | 93.5 | 516 | 483 | 93.6 | 592 | 98.0 | 116 | 483 | 12 | 0 | 0 | | Challenge | 85 | 81 | 95.3 | 62 | 58 | 93.5 | 81 | 95.3 | 30 | 52 | 4 | 0 | 0 | | Combined | 689 | 646 | 93.8 | 578 | 541 | 93.6 | 673 | 97.7 | 146 | 535 | 16 | 0 | 0 | | Salmonella spp. – Breakpoints ≤0.06, 0.12 – 0.5, ≥1 μg/mL | | | | | | | | | | | | | | | Clinical | 19 | 19 | 100.0 | 19 | 19 | 100 | 19 | 100. | 0 | 17 | 0 | 0 | 0 | | Challenge | 2 | 2 | 100.0 | 1 | 1 | 100 | 1 | 50.0 | 1 | 1 | 1 | 0 | 0 | | Combined | 21 | 21 | 100.0 | 20 | 20 | 100 | 20 | 95.2 | 1 | 18 | 0 | 0 | 0 | | P. aeruginosa – Breakpoints ≤0.5, 1, ≥2 μg/mL | | | | | | | | | | | | | | | Clinical | 79 | 74 | 93.7 | 70 | 65 | 92.9 | 74 | 93.7 | 23 | 54 | 4 | 1 | 0 | | Challenge | 14 | 14 | 100.0 | 14 | 14 | 100. | 11 | 78.6 | 6 | 4 | 3 | 0 | 0 | | Combined | 93 | 88 | 94.6 | 84 | 79 | 94.0 | 85 | 91.4 | 29 | 58 | 7 | 1 | 0 | a No results recorded for one challenge isolate of Shigella flexneri with WalkAway EA - Essential agreement S - Susceptible EVAL - Evaluable isolates min - minor discrepancies CA - Category agreement maj - major discrepancies R - Resistant vmj - very major discrepancies Essential agreement (EA) occurs when the result of the reference method and that of the MicroScan Dried Gram-Negative MIC/Combo Panel are within plus or minus one serial two-fold dilution of the antibiotic. Evaluable results are those that are on scale for both the reference method and the MicroScan Dried Gram-Negative MIC/Combo Panel. Category agreement (CA) occurs when the interpretation of the result of the reference method agrees exactly with the interpretation provided by the MicroScan Dried Gram-Negative MIC/Combo Panel. Table 5. Performance of MicroScan Dried Gram-Negative Panels with Ciprofloxacin, Using Turbidity Inoculation and all Read Methods | | Tot | No. EA | EA % | Eval EA Tot | No. Eval EA | Eval EA % | No. CA | CA % | No. R | No. S | mi n | maj | vmj | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | WalkAway Read | | | | | | | | | | | | | | | Enterobacteriaceae – Breakpoints ≤0.25, 0.5, ≥1 μg/mL | | | | | | | | | | | | | | | Clinical | 604 | 580 | 96.0 | 514 | 493 | 95.9 | 595 | 98.5 | 116 | 483 | 9 | 0 | 0 | | Challenge | 84a | 83 | 98.8 | 62 | 61 | 98.4 | 80 | 95.2 | 30 | 51 | 4 | 0 | 0 | | Combined | 688 | 663 | 96.4 | 576 | 554 | 96.2 | 675 | 98.1 | 146 | 534 | 13 | 0 | 0 | | Salmonella spp. – Breakpoints ≤0.06, 0.12 – 0.5, ≥1 μg/mL | | | | | | | | | | | | | | | Clinical | 19 | 19 | 100 | 19 | 19 | 100 | 19 | 100 | 0 | 17 | 0 | 0 | 0 | | Challenge | 2 | 2 | 100 | 1 | 1 | 100 | 1 | 50.0 | 1 | 1 | 1 | 0 | 0 | | Combined | 21 | 21 | 100 | 20 | 20 | 100 | 20 | 95.2 | 1 | 18 | 0 | 0 | 0 | | P. aeruginosa – Breakpoints ≤0.5, 1, ≥2 μg/mL | | | | | | | | | | | | | | | Clinical | 79 | 78 | 98.7 | 70 | 69 | 98.6 | 74 | 93.7 | 23 | 54 | 5 | 0 | 0 | | Challenge | 14 | 13 | 92.9 | 14 | 13 | 92.9 | 11 | 78.6 | 6 | 4 | 3 | 0 | 0 | | Combined | 93 | 91 | 97.8 | 84 | 82 | 97.6 | 85 | 91.4 | 29 | 58 | 8 | 0 | 0 | K193536 - Page 10 of 16 {10} | | Tot | No. EA | EA % | Eval EA Tot | No. Eval EA | Eval EA % | No. CA | CA % | No. R | No. S | mi n | maj | vmj | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | autoSCAN-4 Read | | | | | | | | | | | | | | | Enterobacteriaceae – Breakpoints ≤0.25, 0.5, ≥1 μg/mL | | | | | | | | | | | | | | | Clinical | 604 | 584 | 96.7 | 514 | 496 | 96.5 | 595 | 98.5 | 116 | 483 | 9 | 0 | 0 | | Challenge | 85 | 82 | 96.5 | 63 | 60 | 95.3 | 80 | 94.1 | 30 | 52 | 5 | 0 | 0 | | Combined | 689 | 666 | 96.7 | 577 | 556 | 96.4 | 675 | 98.0 | 146 | 535 | 14 | 0 | 0 | | Salmonella spp. – Breakpoints ≤0.06, 0.12 – 0.5, ≥1 μg/mL | | | | | | | | | | | | | | | Clinical | 19 | 19 | 100.0 | 19 | 19 | 100. | 19 | 100.0 | 0 | 17 | 0 | 0 | 0 | | Challenge | 2 | 2 | 100.0 | 1 | 1 | 100. | 1 | 50.0 | 1 | 1 | 1 | 0 | 0 | | Combined | 21 | 21 | 100.0 | 20 | 20 | 100. | 20 | 95.2 | 1 | 18 | 0 | 0 | 0 | | P. aeruginosa – Breakpoints ≤0.5, 1, ≥2 μg/mL | | | | | | | | | | | | | | | Clinical | 79 | 74 | 93.7 | 70 | 65 | 92.9 | 71 | 89.9 | 23 | 54 | 7 | 0 | 1 | | Challenge | 14 | 14 | 100.0 | 14 | 14 | 100. | 11 | 78.6 | 6 | 4 | 3 | 0 | 0 | | Combined | 93 | 88 | 94.6 | 84 | 79 | 94.0 | 82 | 88.2 | 29 | 58 | 10 | 0 | 1 | | | | | | | | | | | | | | | | | Manual Read | | | | | | | | | | | | | | | Enterobacteriaceae – Breakpoints ≤0.25, 0.5, ≥1 μg/mL | | | | | | | | | | | | | | | Clinical | 604 | 578 | 95.7 | 515 | 493 | 95.7 | 596 | 98.7 | 116 | 483 | 8 | 0 | 0 | | Challenge | 85 | 84 | 98.8 | 63 | 62 | 98.4 | 80 | 94.1 | 30 | 52 | 5 | 0 | 0 | | Combined | 689 | 662 | 96.1 | 578 | 555 | 96.0 | 676 | 98.1 | 146 | 535 | 13 | 0 | 0 | | Salmonella spp. – Breakpoints ≤0.06, 0.12 – 0.5, ≥1 μg/mL | | | | | | | | | | | | | | | Clinical | 19 | 19 | 100.0 | 19 | 19 | 100 | 19 | 100.0 | 0 | 17 | 0 | 0 | 0 | | Challenge | 2 | 2 | 100.0 | 1 | 1 | 100 | 1 | 50.0 | 1 | 1 | 1 | 0 | 0 | | Combined | 21 | 21 | 100.0 | 20 | 20 | 100 | 20 | 95.2 | 1 | 18 | 0 | 0 | 0 | | P. aeruginosa – Breakpoints ≤0.5, 1, ≥2 μg/mL | | | | | | | | | | | | | | | Clinical | 79 | 78 | 98.7 | 70 | 69 | 98.6 | 75 | 94.9 | 23 | 54 | 4 | 0 | 0 | | Challenge | 14 | 14 | 100.0 | 14 | 14 | 100 | 11 | 78.6 | 6 | 4 | 3 | 0 | 0 | | Combined | 93 | 92 | 98.9 | 84 | 83 | 98.8 | 86 | 92.5 | 29 | 58 | 7 | 0 | 0 | a No results recorded for one challenge isolate of Shigella flexneri with WalkAway see above For C. koseri, P. vulgaris, S. sonnei and Salmonella enteritidis, no resistant isolates were available for evaluation during clinical or challenge testing. The sponsor included the following limitation in the device labeling: The ability of the MicroScan Dried Gram Negative Panels to detect resistance to ciprofloxacin is unknown for the following species because an insufficient number of resistant strains were available at the time of comparative testing: C. koseri, P vulgaris, Shigella sonnei and Salmonella enteritidis. Isolates yielding MIC results suggestive of a resistant interpretive category should be submitted to a reference laboratory. For tests inoculated using the Prompt Inoculation System, E. cloacae showed low essential agreement with all read methods, K. (Enterobacter) aerogenes showed low essential agreement with the WalkAway and Manual read method, S. sonnei showed low EA and CA (due to minor errors) and S. marcescens showed low essential agreement with the autoSCAN-4 and manual read methods. In addition, isolates of C. koseri inoculated with the turbidity inoculation method and read manually showed low essential agreement as compared to the reference method. The sponsor included the following limitation in the device labeling: K193536 - Page 11 of 16 {11} Results obtained with ciprofloxacin and E. cloacae with all read methods/Prompt, E. aerogenes with WalkAway/Prompt and manual/Prompt, S. sonnei with manual/Prompt and S. marcescens with the autoSCAN-4/Prompt and manual/Prompt have shown discrepant MICs when compared with the reference method. If critical to patient care, isolates of those species should be retested using the turbidity inoculation method. In addition, discrepant MICs were observed with ciprofloxacin and C. koseri with turbidity/manual read; if critical to patient care, isolates of C. koseri should be tested with an alternate inoculation/read method. P. aeruginosa was observed to have lowered categorical agreement and an elevated very major error rate with the autoSCAN-4 read method and both turbidity and Prompt inoculation method during the initial clinical and challenge testing. Additional testing with P. aeruginosa challenge isolates was reviewed (29 isolates tested with Prompt and turbidity/auto-SCAN-4 and manual read methods, 23 isolates tested with Prompt and turbidity/WalkAway). Results of the original clinical and challenge testing combined with the additional challenge testing showed improved categorical agreement and very major error rate with turbidity inoculation and autoSCAN-4; an elevated very major error rate remained with Prompt/autoSCAN-4 (Table 6 below). The sponsor included the following limitation in the device labeling: Due to low categorical agreement and increased occurrence of very major errors for P. aeruginosa and ciprofloxacin with the autoSCAN-4 and Prompt inoculation, results should be confirmed by manual read prior to reporting. Table 6. Results of testing P. aeruginosa with all inoculation and read methods including additional challenge isolates. | | Tot | No. EA | EA % | Eval EA Tot | No. Eval EA | Eval EA % | No. CA | CA % | No. R | No. S | min | maj | vmj | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | Prompt Inoculation | | | | | | | | | | | | | | | WalkAway | 116 | 113 | 97.4 | 91 | 88 | 96.7 | 113 | 97.4 | 46 | 64 | 8 | 1 | 0 | | autoSCAN-4 | 122 | 116 | 95.1 | 94 | 90 | 95.7 | 107 | 87.7 | 48 | 68 | 12 | 1 | 2 | | Manual | 122 | 117 | 95.9 | 95 | 91 | 95.8 | 114 | 93.4 | 48 | 68 | 7 | 1 | 0 | | | | | | | | | | | | | | | | | Turbidity Inoculation | | | | | | | | | | | | | | | WalkAway | 116 | 114 | 98.3 | 92 | 90 | 97.8 | 113 | 97.4 | 46 | 64 | 9 | 0 | 0 | | autoSCAN-4 | 122 | 117 | 95.9 | 95 | 91 | 95.8 | 111 | 91.0 | 48 | 68 | 10 | 0 | 1 | | Manual | 122 | 121 | 99.2 | 96 | 95 | 99.0 | 115 | 94.3 | 48 | 68 | 7 | 0 | 0 | ## Testing/Reporting MIC for Non-indicated Species: For this review, the interpretative criteria are applied to the organisms/organism groups according to the FDA STIC website. As required under 511A(2)(2)(B) of the Federal Food, Drug and Cosmetic Act, the following statement is added to the Warnings and Precautions section of the device labeling: The safety and efficacy of antimicrobial drugs, for which antimicrobial susceptibility is tested by this AST device, may or may not have been established in adequate and well-controlled clinical trials for treating clinical infections due to microorganisms outside of those found in the indications and usage in the drug label. The clinical significance of K193536 - Page 12 of 16 {12} susceptibility information in those instances is unknown. The approved labeling for specific antimicrobial drugs provides the uses for which the antimicrobial drug is approved. # Trending An analysis of trending was conducted using the combined clinical and challenge data for each organism group and for each inoculation and read method. This trending calculation takes into account MIC values that are determined to be one or more doubling dilution lower or higher compared to the reference method irrespective of whether the device MIC values are on scale or not. Results that are not clearly at least one dilution lower, at least one dilution higher or in exact agreement with the CLSI reference method are not considered in the trending analysis. Trending results for indicated species were evaluated to determine if species-specific trends were observed. Species or organism groups for which the difference between the percentage of isolates with higher vs. lower readings was $>30\%$ and for which the confidence interval was determined to be statistically significant were considered to show evidence of trending. Trending that provides higher or lower MIC values compared to the reference is addressed in labeling. Trending calculations for ciprofloxacin with Enterobacteriaceae, Salmonella spp., P. aeruginosa and species for which trending was observed are shown in Table 7 below. To address the observed trending the sponsor included the following footnote to the performance table in the device labeling: Ciprofloxacin MIC values for Enterobacteriaceae were most frequently in exact agreement with the reference method. When not in agreement results tended to be one doubling dilution higher for: C. freundii (Turbidity/WalkAway and manual read), C. koseri and Shigella sonnei (Prompt and Turbidity/all read methods), M. morganii (Prompt/WalkAway and manual read, Turbidity/manual read), Salmonella ser. Typhi (Prompt/WalkAway and manual read, Turbidity/WalkAway and manual read), and Salmonella spp. (Turbidity/WalkAway). MIC results for P. rettgeri tended to be one doubling dilution lower with Prompt and Turbidity inoculation with auto-SCAN-4. Table 7. Trending Observed for Ciprofloxacin ${}^{a}$ | Inoculation/ Read Method | Organism | Total Evaluable for Trending | ≥1 Dilution lower No. (%) | Exact No. (%) | ≥1 Dilution Higher No. (%) | Percent Difference (CI) | Trending Noted | | --- | --- | --- | --- | --- | --- | --- | --- | | Prompt/WalkAway | Enterobacteriaceae | 513 | 79 (15.4) | 261 (50.9) | 173 (33.7) | 18.3 (13.1 to 23.4) | No | | | Salmonella spp. | 20 | 0 | 16 (80.0) | 4 (20.0) | 20.0 (-0.1 to 41.6) | No | | | P. aeruginosa | 83 | 10 (12.1) | 59 (71.1) | 14 (16.9) | 4.8 (-6.1 to 15.7) | No | | | C. koseri | 51 | 1 (2.0) | 15 (29.4) | 35 (68.6) | 66.7 (50.7 to 77.8) | Yes | | | M. morganii | 27 | 2 (7.4) | 14 (51.9) | 11 (40.7) | 33.3 (10.6 to 52.6) | Yes | | | S. sonnei | 15 | 0 | 4 (26.7) | 11 (73.3) | 73.3 (40.9 to 89.1) | Yes | | Prompt/autoSCAN-4 | Enterobacteriaceae | 517 | 123 (23.8) | 264 (51.1) | 130 (25.1) | 1.4 (-3.9 to 6.6) | No | K193536 - Page 13 of 16 {13} | Inoculation/ Read Method | Organism | Total Evaluable for Trending | ≥1 Dilution lower No. (%) | Exact No. (%) | ≥1 Dilution Higher No. (%) | Percent Difference (CI) | Trending Noted | | --- | --- | --- | --- | --- | --- | --- | --- | | | Salmonella spp. | 20 | 0 | 19 (95.0) | 1 (5.0) | 5.0 (-11.6 to 23.6) | No | | | P. aeruginosa | 84 | 25 (29.8) | 52 (61.9) | 7 (8.3) | -21.4 (-32.7 to -9.7) | No | | | C. koseri | 51 | 3 (5.9) | 18 (35.3) | 30 (58.8) | 52.9 (36.0 to 66.0) | Yes | | | P. rettgeri | 19 | 9 (47.4) | 9 (47.4) | 1 (5.3) | -42.1 (-63.5 to -14.2) | Yes | | | S. sonnei | 15 | 1 (6.7) | 4 (26.7) | 10 (66.7) | 60.0 (26.0 to 79.0) | Yes | | Prompt/ Manual | Enterobacteriaceae | 517 | 82 (15.9) | 255 (49.3) | 180 (34.8) | 19.0 (13.7 to 24.1) | No | | | Salmonella spp. | 20 | 0 | 16 (80.0) | 4 (20.0) | 20.0 (-0.1 to 41.6) | No | | | P. aeruginosa | 83 | 11 (13.3) | 50 (60.2) | 22 (26.5) | 13.3 (1.1 to 25.1) | No | | | C. koseri | 51 | 2 (3.9) | 10 (19.6) | 39 (76.5) | 72.6 (56.4 to 82.5) | Yes | | | M. morganii | 28 | 2 (7.1) | 15 (53.6) | 11 (39.3) | 32.1 (10.1 to 51.2) | Yes | | | S. flexneri | 8 | 0 | 5 (62.5) | 3 (37.5) | 37.5 (-2.7 to 69.4) | Yesb | | | S. sonnei | 15 | 0 | 5 (33.3) | 10 (66.7) | 66.7 (34.4 to 84.8) | Yes | | Turbidity/ WalkAway | Enterobacteriaceae | 510 | 65 (12.8) | 284 (55.7) | 161 (31.6) | 18.8 (13.8 to 23.7) | No | | | Salmonella spp. | 20 | 0 | 14 (70.0) | 6 (30.0) | 30.0 (7.7 to 51.9) | Yes | | | P. aeruginosa | 84 | 16 (19.1) | 58 (69.1) | 10 (11.9) | -7.1 | No | | | C. freundii | 12 | 0 | 7 (58.3) | 5 (41.7) | 41.7 (8.7 to 68.1) | Yes | | | C. koseri | 51 | 1 (2.0) | 13 (25.5) | 37 (72.6) | 70.6 (54.7 to 81.1) | Yes | | | S. sonnei | 15 | 0 | 5 (33.3) | 10 (66.7) | 66.7 (34.4 to 84.8) | Yes | | Turbidity/ autoSCAN-4 | Enterobacteriaceae | 509 | 117 (23.0) | 284 (55.8) | 108 (21.2) | -1.8 (-6.9 to 3.3) | No | | | Salmonella spp. | 20 | 0 | 16 (80.0) | 4 (20.0) | 20.0 (-0.1 to 41.6) | No | | | P. aeruginosa | 84 | 31 (36.9) | 47 (56.0) | 6 (7.1) | -29.8 (-41.1 to -17.6) | No | | | C. koseri | 51 | 4 (7.8) | 21 (41.2) | 26 (51.0) | 43.1 (26.1 to 57.1) | Yes | | | P. rettgeri | 19 | 7 (36.8) | 12 (63.2) | 0 | -36.8 (-59.0 to -12.4) | Yes | | | S. sonnei | 15 | 0 | 5 (33.3) | 10 (66.7) | 66.7 (34.4 to 84.8) | Yes | | Turbidity/ Manual | Enterobacteriaceae | 517 | 74 (14.3) | 274 (53.0) | 169 (32.7) | 18.4 (13.3 to 23.4) | No | | | Salmonella spp. | 20 | 0 | 16 (80.0) | 4 (20.0) | 20.0 (-0.1 to 41.6) | No | | | P. aeruginosa | 84 | 17 (20.2) | 58 (69.1) | 9 (10.7) | -9.5 (-20.5 to 1.6) | No | | | C. freundii | 12 | 0 | 6 (50.0) | 6 (50.0) | 50.0 (15.4 to 74.6) | Yes | | | C. koseri | 51 | 1 (2.0) | 13 (25.5) | 37 (72.6) | 70.6 (54.7 to 81.1) | Yes | | | M. morganii | 26 | 1 (3.9) | 14 | 11 | 38.5 (15.9 | Yes | K193536 - Page 14 of 16 {14} | Inoculation/Read Method | Organism | Total Evaluable for Trending | ≥1 Dilution lower No. (%) | Exact No. (%) | ≥1 Dilution Higher No. (%) | Percent Difference (CI) | Trending Noted | | --- | --- | --- | --- | --- | --- | --- | --- | | | | | | (53.9) | (42.3) | to 57.5) | | | | S. flexneri | 8 | 0 | 5 (62.5) | 3 (37.5) | 37.5 (-2.7 to 69.4) | Yes^{b} | | | S. sonnei | 15 | 0 | 5 (33.3) | 10 (66.7) | 66.7 (34.4 to 84.8) | Yes | a See K172912 for trending results for Salmonella ser.Typhi b Not statistically significant ## Resistance Mechanism Characterization Challenge isolates of Enterobacteriaceae and P. aeruginosa harboring various molecular mechanisms of resistance were tested with ciprofloxacin. Isolates from the CDC and FDA Antibiotic Resistance Isolate Bank were evaluated. No isolates harboring gyrA, gyrB, parC or parE were tested. 2. **Matrix Comparison:** Not Applicable ## C Clinical Studies: 1. **Clinical Sensitivity:** Not Applicable 2. **Clinical Specificity:** Not Applicable 3. **Other Clinical Supportive Data (When 1. and 2. Are Not Applicable):** Not Applicable ## D Clinical Cut-Off: Not Applicable ## E Expected Values/Reference Range: The FDA-recognized breakpoints for ciprofloxacin are shown in Table 8 below. K193536 - Page 15 of 16 {15} K193536 - Page 16 of 16 Table 8. FDA-Recognized Interpretive Criteria for Ciprofloxacin | Organism | Interpretive Criteria for Ciprofloxacin MIC (μg/mL)a | | | | --- | --- | --- | --- | | | Susceptible | Intermediate | Resistant | | Enterobacteriaceae | ≤0.25 | 0.5 | ≥1 | | Salmonella spp. | ≤0.06 | 0.12 -0.5 | ≥1 | | P. aeruginosa | ≤0.5 | 1 | ≥2 | a FDA STIC Webpage VIII Proposed Labeling: The labeling supports the finding of substantial equivalence for this device. IX Conclusion: The submitted information in this premarket notification is complete and supports a substantial equivalence decision. To support the implementation of changes to FDA-recognized susceptibility test interpretive criteria (i.e., breakpoints), this submission included a breakpoint change protocol that was reviewed and accepted by FDA. This protocol addresses future revisions to device labeling in response to breakpoint changes that are recognized on the FDA STIC webpage (https://www.fda.gov/Drugs/DevelopmentApprovalProcess/DevelopmentResources/ucm410971.htm). The protocol outlined the specific procedures and acceptance criteria that Beckman Coulter intends to use to evaluate the MicroScan Dried Gram-Negative MIC/Combo Panels with Ciprofloxacin (Cp) (0.004 – 8 μg/mL) when revised breakpoints for ciprofloxacin are published on the FDA STIC webpage. The breakpoint change protocol included with the submission indicated that if specific criteria are met, Beckman Coulter will update the ciprofloxacin device label to include (1) the new breakpoints, (2) an updated performance section after re-evaluation of data in this premarket notification with the new breakpoints, and (3) any new limitations as determined by their evaluation.