← Product Code [JWY](/productcode/JWY) · K081182

# MICROSCAN DRIED GRAM-POSITIVE MIC/COMBO PANELS NEW ANTIMICROBIAL TEST - INDUCIBLE CLINDAMYCIN (K081182)

_Siemens · JWY · Aug 8, 2008 · Microbiology · SESE_

**Canonical URL:** https://fda-staging.innolitics.com/device/K081182

## Device Facts

- **Applicant:** Siemens
- **Product Code:** [JWY](/productcode/JWY.md)
- **Decision Date:** Aug 8, 2008
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 866.1640
- **Device Class:** Class 2
- **Review Panel:** Microbiology

## Indications for Use

The MicroScan Inducible Clindamycin test (ICd) is intended for use with the MicroScan® Dried Gram Positive MIC/Combo Dried Gram Positive Breakpoint Combo and Dried Gram Positive ID Type 2 panels. MicroScan® Positive panels are designed for use in determining antimicrobial agent susceptibility and/or identification to the species level of rapidly growing aerobic and facultative anaerobic gram-positive cocci, some fastidious aerobic gram positive cocci and Listeria monocytogenes. Refer to Limitation of Procedure Section for use with fastidious streptococci.

## Device Story

MicroScan Dried Gram-Positive MIC/Combo Panels detect inducible clindamycin resistance in Staphylococcus species. Device uses dehydrated microdilutions of 4 mcg/ml erythromycin and 0.5 mcg/ml clindamycin in Mueller Hinton Broth. Inoculum prepared via turbidity or Prompt method; panels incubated 16-24 hours at 35°C. Growth measured visually or via automated instrumentation (autoScan 4, WalkAway). Growth algorithms in instruments detect inhibition; results reported as MIC and categorical interpretation. Used in clinical microbiology laboratories by technicians. Output informs clinicians on clindamycin resistance status, guiding antimicrobial therapy decisions.

## Clinical Evidence

Performance validated via clinical trials at three sites using 380 fresh and stock gram-positive isolates (268 S. aureus, 54 S. epidermidis, 58 coagulase-negative Staphylococcus). Comparison against CLSI reference broth dilution method showed 98.1-100% Category Agreement. Challenge study (n=75) confirmed 100% CA across all read methods (manual, WalkAway, autoSCAN4) and inoculation methods (turbidity, Prompt). Reproducibility >99%.

## Technological Characteristics

Miniaturized broth microdilution panel; dehydrated antimicrobial agents; rehydrated with water. Dimensions/form factor: standard microdilution panel. Energy source: non-CO2 incubator. Connectivity: compatible with autoSCAN-4 and WalkAway instrumentation. Software: automated reading capability. Sterilization: not specified.

## Regulatory Identification

An antimicrobial susceptibility test powder is a device that consists of an antimicrobial drug powder packaged in vials in specified amounts and intended for use in clinical laboratories for determining in vitro susceptibility of bacterial pathogens to these therapeutic agents. Test results are used to determine the antimicrobial agent of choice in the treatment of bacterial diseases.

## Predicate Devices

- MicroScan Dried Gram-Positive MIC/Combo Panels ([K081182](/device/K081182.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.
>
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# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY ASSAY ONLY TEMPLATE

A. 510(k) Number:
K081182

B. Purpose for Submission:
Addition of a new antimicrobial test- Inducible Clindamycin test for the MicroScan® Dried Gram-Positive MIC/Combo panels

C. Measurand:
Inducible Clindamycin: 4 mcg/ml erythromycin and 0.5 mcg/ml clindamycin

D. Type of Test:
Quantitative and Qualitative growth based detection algorithm

E. Applicant:
Siemens Healthcare Diagnostics Inc.

F. Proprietary and Established Names:
MicroScan® Dried Gram-Positive MIC/Combo Panels with the Inducible Clindamycin test

G. Regulatory Information:
1. Regulation section:
866.1640 Antimicrobial Susceptibility Test (AST) Powder
2. Classification:
II
3. Product code:
JWY Manual Antimicrobial Susceptibility Test Systems
LRG-Instrument for Auto Reader & Interpretation of Overnight Antimicrobial Susceptibility Systems

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LTT – Panels, Test, Susceptibility, Antimicrobial
LTW – Susceptibility Test Cards, Antimicrobial

4. Panel:
83 Microbiology

H. Intended Use:

1. Intended use(s):
The MicroScan Inducible Clindamycin test (ICd) is intended for use with the MicroScan® Dried Gram Positive MIC/Combo Dried Gram Positive Breakpoint Combo and Dried Gram Positive ID Type 2 panels. MicroScan® Positive panels are designed for use in determining antimicrobial agent susceptibility and/or identification to the species level of rapidly growing aerobic and facultative anaerobic gram-positive cocci, some fastidious aerobic gram positive cocci and Listeria monocytogenes. Refer to Limitation of Procedure Section for use with fastidious streptococci.

2. Indication(s) for use:
The MicroScan Dried Gram Positive 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-positive cocci. After inoculation, panels are incubated for 16 – 24 hours at 35° Celsius plus or minus 1° Celsius in a non-CO₂ incubator and reads either visually or with MicroScan® instrumentation, according to the package insert.

The MicroScan Inducible Clindamycin test (ICd) is intended to detect inducible clindamycin resistance in staphylococci in a broth microdilution system. The ICd test applies to isolates that are erythromycin resistant or intermediate and clindamycin susceptible or intermediate.

This submission is for the addition of the Inducible Clindamycin test, consisting of 4 mcg/ml of erythromycin and 0.5 mcg/ml of clindamycin, to the test panel. The Gram positive organisms which may be used for the Inducible Clindamycin test in this panel are: Staphylococcus species.

3. Special conditions for use statement(s):
For prescription use only

The Prompt method of inoculation is an alternate method of inoculation preparation that is supported in the methodology along with the turbidity. The log and stationary inoculum methods should not be used with the Inducible Clindamycin test.

2

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4. Special instrument requirements:

These panels can be read at $\geq 16$ hours of incubation either manually, automatically on the autoScan® 4, or with the WalkAway® instrument systems.

I. Device Description:

The MicroScan® Dried Gram-Positive MIC/Combo Panel contains microdilutions of each antimicrobial agent in various concentrations with Mueller Hinton Broth and various nutrients which are dehydrated and dried in panels. Each panel contains two control wells: a no-growth control well (contains water only/no nutrients or broth), and a growth control well (contains test medium without antibiotic). The panel is rehydrated and inoculated at the same time with $0.1\mathrm{ml}$ of suspension prepared by the turbidity method (inoculum prepared in water, then $0.1\mathrm{ml}$ transferred to $25\mathrm{ml}$ of inoculum water containing pluronic-D/F-a wetting solution) for a final inoculum concentration of $3 - 7\times 10^{5}$. The Prompt® method of inoculation is also recommended as an alternate means of preparing the inoculum. The panels are incubated at $35^{\circ}\mathrm{C}$ in a non- $\mathrm{CO}_{2}$ for 16-20 hours and read by visual observation of growth. Panels may also be read automatically with the WalkAway® or the AutoScan®4.

J. Substantial Equivalence Information:

1. Predicate device name(s):

MicroScan Dried Gram Positive MIC/Combo Panels

2. Predicate K number(s):

K862140

3. Comparison with predicate:

|  Similarities  |   |   |
| --- | --- | --- |
|  Item | Device | Predicate  |
|  Intended Use | Detection of inducible clindamycin resistance in staphylococci | Determination of susceptibility to antimicrobials with gram-positive bacteria  |
|  Technology | Overnight microdilution MIC susceptibility tests | Same  |
|  Inoculum Preparation | Inoculum prepared from isolated colonies using either the Turbidity method or Prompt system. | Same  |

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|  Similarities  |   |   |
| --- | --- | --- |
|  Item | Device | Predicate  |
|  Instrument | autoSCAN® 4, or with the WalkAway® | Same  |
|  Results | Report results as minimum inhibitory concentration (MIC) and categorical interpretation (SIR) | Same  |
|  Differences  |   |   |
| --- | --- | --- |
|  Item | Device | Predicate  |
|  Antibiotic | 4 ug/ml erythromycin 0.5 ug/ml clindamycin | Varies according to antibiotic  |
|  Limitations | The performance of the Inducible Clindamycin test has not been established with Stationary and Log Inoculum methods. Inoculum should be prepared with turbidity or Prompt® method. | None  |
|  Test organism | Staphylococcus spp. | Varies according to antibiotic  |

# K. Standard/Guidance Document Referenced (if applicable):

Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA"; Clinical and Laboratory Standards Institute (CLSI), Document M100-S18: "Performance Standards for Antimicrobial Susceptibility Testing; Approved Standard".

# L. Test Principle:

After incubation in a non- $\mathrm{CO}_{2}$  incubator for 16-20 hours, the minimum inhibitory concentration (MIC) for the test organisms are read by determining the lowest antimicrobial concentration showing inhibition of growth. The panels are read either manually using the MicroScan® Microdilution Viewer or with the autoSCAN® 4 or the WalkAway® instruments, which uses an optics systems with growth algorithms to directly measure organism growth.

# M. Performance Characteristics (if/when applicable):

# 1. Analytical performance:

a. Precision/Reproducibility:

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Reproducibility was verified using 10 isolates at three clinical trial sites. Each strain was tested at each site in replicates of three over three days (total of 27 replicates per strain). The two inoculum methods tested were the turbidity and prompt with readings performed using the MicroScan® Microdilution Viewer or with the autoSCAN® 4 or the WalkAway® instruments. Acceptable reproducibility was demonstrated with >99% Agreement for all sites combined.

b. Linearity/assay reportable range:

Not applicable

c. Traceability, Stability, Expected values (controls, calibrators, or methods):

Quality control was performed daily using three staphylococci strains, S. aureus ATCC 29213, S. aureus ATCC BAA-976 and S. aureus ATCC BAA-977 as recommended by CLSI. Testing was performed using both the turbidity and prompt inoculation methods and all read methods (manually or with the autoSCAN® 4 or the WalkAway® instruments) with the following results and expected ranges as stated. The values repeat the number of times a result was obtained at each concentration.

QC Table

|  Organism | Conc. In ug/mL | Reference result Turbidity inoc. | Turbidity inoculation with Read methods |   |   | Prompt® inoculation with Read  |   |   |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
|   |   |   |  Manual | Walk-Away® | Auto-Scan® | Manual | Walk-Away® | Auto-Scan®  |
|  |   |   |   |   |   |   |   |   |
|  S. aureus BAA 976 Exp. Range: ≤4 ug/mL | ≤4/0.5 | 109 | 110 | 69 | 71 | 119 | 116 | 118  |
|   |  >4/0.5 |  |  | 1 |  | 3 | 2 | 6  |
|   |  |   |   |   |   |   |   |   |
|   |  |   |   |   |   |   |   |   |
|  |   |   |   |   |   |   |   |   |
|  S. aureus BAA 977 Exp. Range: >4 ug/mL | ≤4/0.5 |  |  |  |  | 2 | 1 | 1  |
|   |  >4/0.5 | 110 | 110 | 70 | 71 | 123 | 119 | 126  |
|   |  |   |   |   |   |   |   |   |
|   |  |   |   |   |   |   |   |   |
|  |   |   |   |   |   |   |   |   |
|  S. aureus ATCC 29213 Exp. Range: ≤4 ug/mL | ≤4/0.5 | 112 | 110 | 69 | 71 | 124 | 120 | 125  |
|   |  >4/0.5 |  |  |  |  |  |  | 2  |
|   |  |   |   |   |   |   |   |   |
|   |  |   |   |   |   |   |   |   |
|  |   |   |   |   |   |   |   |   |

Quality control results demonstrated the ability of all variables of the procedure (reading and inoculation) to produce acceptable results.

Inoculum density control: A turbidity meter was used for the turbidity inoculation

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method. The Prompt® method of inoculation had colony counts (CC) performed periodically throughout the study to determine the average inoculum density since there is no visual check of the inoculum using this device. The Prompt® inoculation method had an average colony count of $4.69 \times 10^{5}$ CFU/mL for *E. faecalis* ATCC 29212 with a range of $6.0 \times 10^{4}$ to $8.9 \times 10^{5}$ CFU/mL, *S. aureus* BAA 976 had an average colony count of $1.83 \times 10^{6}$ CFU/mL with a range of $2.9 \times 10^{5} - 4.5 \times 10^{6}$ CFU/mL, *S. aureus* BAA 977 had an average colony count of $1.53 \times 10^{6}$ CFU/mL with a range of $4.1 \times 10^{5} - 5.6 \times 10^{6}$ CFU/mL, *S. aureus* ATCC 29213 had an average colony count of $1.82 \times 10^{6}$ CFU/mL with a range of $2.7 \times 10^{5} - 7.9 \times 10^{6}$ CFU/mL. The CFU study demonstrated that the *S. aureus* has a higher concentration of organism that reproduces a more resistant result. The inoculum of the Prompt® method of inoculation generally provides a higher number of CFU with more variability than a method using a turbidity meter.

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 testing was performed at three sites using fresh isolates supplemented with stock isolates of gram positive cocci. A comparison of the MicroScan® Dried Gram-Positive test panel results was made to the reference method as recommended in the CLSI standard M7-A6 with the following deviations from that recommendation: Pluronic-F is used as the inoculum in the frozen reference panels. Pluronic is a wetting agent which provides a smoother draw of liquid into the inoculator. Testing of the reference method and the MicroScan panels was performed at the same time. A challenge set was also tested at one site and compared to the reference broth dilution result mode that was determined by previous testing of each isolate multiple times in the recommended reference panel. All isolates tested grew in the MicroScan panels.

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Summary Table

|   | Total | CA | CA% | # Neg | # Pos | maj | vmj  |
| --- | --- | --- | --- | --- | --- | --- | --- |
|  S. aureus | 268 | 263 | 98.1 | 60 | 208 | 0 | 3  |
|  S. epidermidis | 54 | 54 | 100 | 26 | 28 | 0 | 0  |
|  Coagulase-negative Staphylococcus | 58 | 58 | 100 | 25 | 33 | 0 | 0  |

CA-Category Agreement
maj – major errors
vmj – very major errors

CA is when the interpretation (S–I-R) of the reference method agrees exactly with the interpretation of the MicroScan® result.

Essential Agreement and minor errors are not applicable since the Inducible Clindamycin test is a one dilution test.

The challenge set of organisms was also tested using the Prompt® method and turbidity method of inoculation with all reading methods. This included seventy five challenge isolates that were tested at one site. Organism selection was based on isolates that were erythromycin resistant or intermediate and clindamycin susceptible or intermediate, and included 38 D-zone positive and 37 D-zone negative strains. The inoculum was prepared by the turbidity or Prompt® method and incubated in the WalkAway® instrument. All panels had additional readings performed after the WalkAway® reading was completed using the autoScan®-4 and then manually on the touchSCAN®-SR. The table below demonstrates the numbers that were in exact agreement with the reference method result and those that differed by one or more wells.

|  Read Method | Inoculation Method | Total | CA | CA% | # Pos | # Neg | maj | vmj  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  Manual | Turbidity | 75 | 75 | 100 | 38 | 37 | 0 | 0  |
|  Walkaway | Turbidity | 75 | 75 | 100 | 38 | 37 | 0 | 0  |
|  autoSCAN4 | Turbidity | 75 | 75 | 100 | 38 | 37 | 0 | 0  |
|  Manual | Prompt | 75 | 75 | 100 | 38 | 37 | 0 | 0  |
|  Walkasay | Prompt | 75 | 75 | 100 | 38 | 37 | 0 | 0  |
|  autoSCAN4 | Prompt | 75 | 75 | 100 | 38 | 37 | 0 | 0  |

CA-Category Agreement
maj – major errors
vmj – very major errors

b. Matrix comparison:
Not applicable

3. Clinical studies:
a. Clinical Sensitivity:

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Not applicable

b. Clinical specificity:

Not applicable

c. Other clinical supportive data (when a. and b. are not applicable):

See comparison studies.

4. Clinical cut-off:

Not applicable

5. Expected values/Reference range:

The MicroScan Inducible Clindamycin test uses the result from a single well containing 4 mcg/ml of erythromycin and 0.5 mcg/ml if clindamycin. Isolates that are ICd positive (MIC>4/0.5) are considered to be clindamycin resistant. If ICd is negative (MIC ≤4/0.5), the result indicates no inducible clindamycin resistance and isolates are reported as tested (i.e. clindamycin susceptible or intermediate). The gram-positive organisms which may be reported for the Inducible Clindamycin test in this panel are: Staphylococcus spp.

|  Test | Negative | Positive  |
| --- | --- | --- |
|  Inducible Clindamycin Test-Staphylococci | ≤4/0.5 mcg/ml | >4/0.5 mcg/ml  |

N. Proposed Labeling:

The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10.

O. Conclusion:

The information submitted in this premarket notification is complete and supports a substantial equivalence decision.

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**Source:** [https://fda-staging.innolitics.com/device/K081182](https://fda-staging.innolitics.com/device/K081182)

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