SUSCEPTIBILITY TEST PLATE FOR VANCOMYCIN VRSA LIMITATION REMOVAL

K060783 · Trek Diagnostic Systems, Inc. · JWY · May 16, 2006 · Microbiology

Device Facts

• Record ID: K060783
• Device Name: SUSCEPTIBILITY TEST PLATE FOR VANCOMYCIN VRSA LIMITATION REMOVAL
• Applicant: Trek Diagnostic Systems, Inc.
• Product Code: JWY · Microbiology
• Decision Date: May 16, 2006
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.1640
• Device Class: Class 2

Indications for Use

Vancomycin at 1-128 µg/mL for use with gram positive organisms including VRSA with the Sensititre® MIC Susceptibility system is an in vitro diagnostic product for clinical susceptibility testing of gram negative and gram positive organisms.

Device Story

Sensititre 18-24 hour MIC susceptibility plates are multi-well microtitre plates containing dried, stabilized antimicrobics; used for quantitative and qualitative antimicrobial susceptibility testing. System utilizes fluorescence-based growth detection; non-fluorescent substrate added to inoculum broth produces fluorescent signal proportional to bacterial growth. MIC determined by lowest antimicrobial dilution inhibiting growth. Plates can be read manually via visual turbidity or automatically via fluorescence-based instrumentation. Used in clinical microbiology laboratories to determine antibiotic susceptibility profiles; results guide clinical decision-making for antibiotic therapy. Benefits include standardized, automated susceptibility testing for gram-positive organisms, including VRSA.

Clinical Evidence

Bench testing only. Evaluation used a challenge set of 35 staphylococci and 6 known VRSA clinical isolates. Compared against broth reference method. Combined Essential Agreement (EA) was 100%; Category Agreement (CA) was 95%. No major or very major errors observed. Reproducibility testing across three sites demonstrated >95% reproducibility using 29 strains.

Technological Characteristics

Multi-well plastic microtitre plates; dried, stabilized antimicrobics. Fluorescence-based growth detection principle; non-fluorescent substrate conjugated to enzyme substrates. Manual visual turbidity or automated fluorescence reading. 18-24 hour incubation. Complies with CLSI M7 (M100-S16) standards.

Indications for Use

Indicated for clinical susceptibility testing of gram-positive organisms, specifically Staphylococcus, including Vancomycin-resistant Staphylococcus aureus (VRSA), using Vancomycin at 1-128 µg/mL. Prescription use only.

Regulatory Classification

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.

Submission Summary (Full Text)

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510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION
DECISION SUMMARY
ASSAY ONLY TEMPLATE

A. 510(k) Number:
K060783

B. Purpose for Submission:
To remove a limitation for the detection of vancomycin resistant Staphylococci aureus (VRSA) on Sensititre® 18-24urs MIC susceptibility plates.

C. Measurand:
Vancomycin at 1-128 µg/mL

D. Type of Test:
Antimicrobial Susceptibility Test (Quantitative and Qualitative) growth-based fluorescence

E. Applicant:
TREK Diagnostic Systems INC.

F. Proprietary and Established Names:
Sensititre 18-24 hours MIC susceptibility plates

G. Regulatory Information:
1. Regulation section:
21 CFR 866.1640 Antimicrobial Susceptibility Test Powder
2. Classification:
Class II
3. Product Code:
JWY-manual readings of AST testing of >16 hour incubation
LRG Automated readings of AST of >16 hour incubation
4. Panel:
83 Microbiology

H. Intended Use:
1. Intended use(s):
Vancomycin at 1-128 µg/mL for use with gram positive organisms including VRSA with the Sensititre® MIC Susceptibility system is an in vitro diagnostic product for clinical susceptibility testing of gram negative and gram positive organisms.
2. Indication(s) for use:

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This submission is for the removal of the limitation for the detection of VRSA with the antibiotic Vancomycin at 1-128 µg/mL on the Sensititre® 18-24 hour MIC susceptibility plates for testing staphylococcus.

3. Special condition for use statement(s):

The Sensititre® Gram Positive AST panel detected vancomycin resistance in the VRSA S. aureus strains available at the time of comparative testing. The ability to detect resistance in other S. aureus strains is unknown due to the limited number of resistant strains available for comparative testing.

Prescription Use Only

4. Special instrument Requirements: Not Applicable

I. Device Description:

Sensititre® MIC Susceptibility plate MIC panels are multi-well plastic microtitre plates, precision dosed with dried, stabilized antimicrobics. This is a modification of a microversion of the classic broth dilution methods and can provide both qualitative and quantitative susceptibility results.

J. Substantial Equivalence Information:

1. Predicate device name(s): Pasco MIC and MIC/ID Panels
2. Predicate K number(s): K033119
3. Comparison with predicate:

| Similarities | | |
| --- | --- | --- |
| Item | Device | Predicate |
| Intended use | an in vitro diagnostic product for clinical susceptibility testing of gram negative and gram positive organisms. | same |
| Inoculum | Prepared from colonies using the direct inoculation method | Prepared from colonies using the direct inoculation method |
| Inoculation method | Direct equated to a 0.5 McFarland | Direct equated to a 0.5 McFarland |
| Item | Device | Predicate |

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| Type panel | Dried antibiotics | 100 μl/well frozen |
| --- | --- | --- |
| Incubation | 18-24 hours | 16-24 hours |
| Technology | Fluorescence detection of growth | Turbidity detection of growth |
| Reading method | Visual growth and Auto read by instrumentation | Visual growth |

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 Sensititre® Autoread System utilizes fluorescence technology to read 18-24 hour plates. The technology involves the detection of bacterial growth which is determined by generating a fluorescent product form a non-fluorescent substrate. The non-fluorescent substrate is prepared by conjugating a fluorescent compound to the specific enzyme substrates with a bond which prevents fluorescence. The substrate is added to the inoculum broth and dispensed into the test plates at the same time as the test organism. The amount of fluorescence detected is directly related to the activity of bacterial growth. The MIC is determined by observing the lowest dilution of antimicrobial agent that inhibits growth of the organism. Final results may also be read manually after 18-24 hour incubation by visual observation of turbidity without the use of the fluorescence.

M. Performance Characteristics (if/when applicable):

1. Analytical performance:

a. Precision/Reproducibility

Intersite and Intrasite testing demonstrated >95% reproducibility using 29 strains. The 25 isolate study described in the guidance document was used. These were tested 1 time at each of three sites on each reading method.

b. Linearity/assay reportable range:

Not applicable

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

Ability to provide acceptable Quality Control with the recommended strains was established previously with additional testing during the study. Comparison was made to expected values as established for the well characterized strains.

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Nephelometer was used at each site to standardize the inoculum and it was calibrated each time it was switched on. Colony counts were performed on the quality control isolate with acceptable results for all.

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:

A well characterized challenge set of 35 staphylococci with all but 6 having MICs in the range of testing of vancomycin was used for the evaluation. The testing was performed on the Sensititre® panel and compared to results using the broth reference method. Additionally 6 known VRSA clinical isolates were also tested on the Sensititre® Gram Positive AST Panel with results that were >32 for all isolates. The combined Essential Agreement (EA) for all 41 isolates tested was 100% and the Category Agreement (CA) was 95% with no major or very major errors. Performance was similar when readings were performed manually or on an automatic reader. There was no apparent trending of results for either read method as compared to the reference result.

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:

Interpretative criteria – ≤ 4 μg/ml (S) 8-16 μg/ml (I) and ≥ 32 μg/ml (R)

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N. Labeling:

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

Vancomycin MIC of ≥ 4 µg/mL are recommended for follow up because this is considered an unusual result for staphylococcus.

O. Conclusion:

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