(85 days)
Not Found
No
The description details a standard real-time PCR assay and automated sample preparation, with no mention of AI or ML in the process or analysis.
No
This device is an in vitro diagnostic real-time PCR assay and its stated intended use is "for the direct detection of methicillin-resistant Staphylococus aureus (MRSA) and S.aureus (SA) DNA from nasal swabs to aid in the prevention and control of MRSA and SA infections in healthcare settings." It is explicitly stated that the test "is not intended to diagnose, guide or monitor treatment for MRSA or SA infections". This indicates that it is a diagnostic tool, not a therapeutic one.
Yes
The "Intended Use / Indications for Use" section explicitly states that the device is a "qualitative in vitro diagnostic real-time PCR assay".
No
The device is an in vitro diagnostic system that includes hardware components (cobas x 480 Instrument, cobas z 480 Analyzer) and reagent kits, in addition to the software.
Yes, this device is an IVD (In Vitro Diagnostic).
The "Intended Use / Indications for Use" section explicitly states: "The cobas® MRSA/SA Test on the cobas® 4800 system, is a qualitative in vitro diagnostic real-time PCR assay..."
This statement clearly identifies the device as an in vitro diagnostic product.
N/A
Intended Use / Indications for Use
The cobas® MRSA/SA Test on the cobas® 4800 system, is a qualitative in vitro diagnostic real-time PCR assay, for the direct detection of methicillin-resistant Staphylococcus aureus (MRSA) and S.aureus (SA) DNA from nasal swabs to aid in the prevention and control of MRSA and SA infections in healthcare settings. The cobas® MRSA/SA Test is not intended to diagnose, guide or monitor treatment for MRSA or SA infections, or provide results of susceptibility to methicillin. A negative result does not preclude MRSA/SA nasal colonization. Concomitant cultures are necessary to recover organisms for epidemiology typing or for further susceptibility testing.
Product codes (comma separated list FDA assigned to the subject device)
NQX, OOI
Device Description
The Roche Molecular Systems (RMS) cobas® MRSA/SA Test utilizes real-time polymerase chain reaction (PCR) for the detection of Methicillin resistant Staphylococcus aureus (MRSA) and Staphylococcus aureus (SA) DNA from nasal swab specimens collected in MSwab medium to aid in the prevention and control of MRSA and SA infections in healthcare settings.
The cobas® MRSA/SA Test contains two major processes: (1) automated sample preparation to extract nucleic acids from the nasal swab specimens; (2) PCR amplification of target DNA sequences using MRSA and SA specific primers, and real-time detection of cleaved fluorescent-labeled MRSA and SA specific oligonucleotide detection probes. An Internal Control (IC), containing unrelated randomized DNA sequence, is added to all samples prior to automated sample preparation and is amplified and detected simultaneously with each sample to monitor the entire process.
The MSwab Collection, Transport and Preservation System (Copan Flock Technologies S.r.1.) is used for specimen collection, transportation and storage of specimen for the cobas MRSA/SA Test.
The cobas® MRSA/SA Test utilizes six reagent kits:
- cobas® 4800 MRSA/SA Amplification/Detection Kit
- cobas® 4800 MRSA/SA Controls and Cofactor Kit
- cobas® 4800 System Wash Buffer Kit
- cobas® 4800 System Lysis Kit 1
- cobas 4800 System Internal Control Kit 1
- cobas® 4800 System Sample Preparation Kit
Mentions image processing
Not Found
Mentions AI, DNN, or ML
Not Found
Input Imaging Modality
Not Found
Anatomical Site
Nasal swabs
Indicated Patient Age Range
The majority of subjects were > 50 years of age (67.2%) and ranged in age from 18 to 101 (median age = 57).
Intended User / Care Setting
Healthcare settings.
Description of the training set, sample size, data source, and annotation protocol
Not Found
Description of the test set, sample size, data source, and annotation protocol
Clinical Performance Evaluation Test Set:
- Sample Size: Specimens were collected from 2528 subjects with 2504 (99.1%) evaluable results.
- Data Source: IRB-approved, prospective, multi-site investigation comparing the results with direct chromogenic culture, and direct chromogenic culture combined with enrichment culture (reference method), using nasal swabs from eligible male and female subjects.
- Annotation Protocol:
- One or two swab specimens were collected from each subject; one swab for Standard-of-Care testing (if applicable) and one swab, an MSwab, for the cobas® MRSA/SA Test and for direct and enrichment culture.
- The cobas® MRSA/SA Test was performed at three sites.
- Direct and enrichment culture was performed at a reference laboratory.
- Aliquots of MSwab sample from each subject were transferred directly to one plate each of selective and differential chromogenic media for MRSA and SA (direct culture), and to a tube containing tryptic soy broth (TSB) with 6.5% NaCl (enrichment culture).
- Suspect isolates and positive enrichment broth were cultured to 5% sheep blood agar and isolates identified as SA by Gram-stain and latex agglutination testing.
- Putative MRSA isolates were confirmed using a Kirby-Bauer cefoxitin disc diffusion test for methicillin resistance.
- A MRSA/SA culture positive specimen was defined as a specimen positive for MRSA/SA by either direct or enrichment culture technique.
- A MRSA/SA culture negative specimen was defined as a specimen negative for MRSA/SA for both direct and enrichment culture.
Discrepant Analysis Test Set:
- Sample Size: All samples with discordant results between the cobas® MRSA/SA Test and combined direct and enrichment culture (70 MRSA discordant specimens and 147 SA discordant specimens). A randomly selected subset of 74 samples with concordant results were included as controls.
- Data Source: Leftover MSwab samples.
- Annotation Protocol:
- A second, FDA-cleared nucleic acid amplification test (NAAT) was used.
- A non-selective direct and enrichment culture was performed: aliquot of remnant MSwab sample was transferred to a chocolate agar plate (non-selective direct culture) and to TSB without NaCl (non-selective enrichment culture).
- Isolates recovered from non-selective direct and enrichment culture were characterized as described for the main clinical study.
- Identification of suspicious, atypical isolates were confirmed using a laboratory developed PCR assay for femA and mecA genes.
Summary of Performance Studies (study type, sample size, AUC, MRMC, standalone performance, key results)
Non-Clinical Performance Evaluation:
- Analytical Sensitivity (LOD):
- Determined by analyzing 2 MRSA culture isolates and 1 SA culture isolate.
- Quantified cultures were diluted to 8-9 concentration levels into a simulated nasal swab background matrix.
- LOD determined as the lowest concentration exhibiting at least 95% positive rate for which all higher concentrations were greater than or equal to 95% positive rate.
- Highest claimed LOD between the 2 MRSA strains tested was 700 CFU/swab and for SA it was 700 CFU/swab based on 95% positive rate.
- Genotype LOD Verification:
- Sensitivity determined for 35 additional MRSA culture isolates and 5 additional SA culture isolates.
- LOD ranging from 175 to 750 CFU/swab for 35 MRSA isolates tested.
- LOD of 175 CFU/swab for all 5 SA isolates.
- Geographical Inclusivity:
- Tested 281 MRSA from 16 European countries, US, Japan and Australia, and 85 SA isolates from US.
- 277 of 281 MRSA isolates were detected. All 85 SA isolates were detected.
- Precision:
- Conducted with 2 MRSA culture isolates and 1 SA culture isolate at concentrations below, near and above LOD.
- Total of 36 runs over 12 days, used three unique lots of reagents and three instruments.
- Overall CV% of Ct values for cobas® MRSA/SA Test was ≤ 1.3%, indicating good reproducibility.
- Analytical Specificity:
- Tested non-MRSA/SA microorganisms commonly present in nasal flora, including coagulase negative and positive Staphylococcus species, as well as human cells. Also tested BORSA strains and "empty cassette variants".
- All target negative samples generated negative MRSA and SA results.
- None of the 135 organisms and human cells interfered with the detection of both MRSA and SA targets.
- The cobas® MRSA/SA Test did not generate false negative and false positive results for MRSA in the presence of 2 SA isolates, 10 BORSA, and 13 of 16 mecA dropouts.
- Competitive Inhibition:
- Panels constructed with 2 MRSA isolates and 1 SA isolate at 3 x LOD, and competing Staphylococcus aureus and Methicillin-Resistant Staphylococcus epidermidis (MRSE) isolates at increasing concentrations.
- Increasing concentration of SA or MRSE did not affect the detection of MRSA/SA targets, as shown by stable Ct values.
- Interference:
- 25 commonly used OTC products and antibiotic medicines, as well as whole blood and mucin were tested.
- No interference observed for most OTC products. Rhinaris® Nasal gel and ReleevTM interfered above certain concentrations.
- Test tolerated up to 75% whole blood and 10% mucin.
- Cross Contamination:
- Assessed by testing high titer MRSA and negative samples in a checkerboard configuration.
- 0% observed cross-contamination rate (0/423 MRSA negative samples). No run-to-run carry-over contamination.
Clinical Performance Evaluation:
- Reproducibility:
- Multi-site study using contrived clinical samples across lot, site/instrument, operator, day, and run.
- MRSA-positive percent agreement for "Below LOD MRSA-384" and "Below LOD MRSA-43300" were 85.6% and 87.2%, respectively; all other MRSA-positive panels were 100.0%.
- SA-positive percent agreement for "Below LOD SA", "1 × LOD SA" and "3 × LOD SA" were 50.0%, 99.4%, and 100.0%, respectively.
- Total SD and CV (%) of Ct values were low, indicating high reproducibility.
- Clinical Study:
- Study Type: IRB-approved, prospective, multi-site investigation.
- Sample Size: 2504 evaluable results.
- Key Results (compared to combined direct and enrichment culture):
- MRSA:
- Sensitivity: 93.1% (149/160)
- Specificity: 97.5% (2281/2340)
- SA:
- Sensitivity: 93.9% (620/660)
- Specificity: 94.2% (1734/1841)
- MRSA:
Key Metrics (Sensitivity, Specificity, PPV, NPV, etc.)
Clinical Performance vs. Combined Direct and Enrichment Culture (Reference Method):
- MRSA:
- Sensitivity: 93.1% (149/160) (95% CI: 88.1-96.1%)
- Specificity: 97.5% (2281/2340) (95% CI: 96.8-98.0%)
- Prevalence: 6.4%
- PPV: 71.6%
- NPV: 99.5%
- SA:
- Sensitivity: 93.9% (620/660) (95% CI: 91.9-95.5%)
- Specificity: 94.2% (1734/1841) (95% CI: 93.0-95.2%)
- Prevalence: 26.4%
- PPV: 85.3%
- NPV: 97.7%
Clinical Performance vs. Direct Culture:
- MRSA:
- Positive Percent Agreement: 97.1% (135/139) (95% CI: 92.8-98.9%)
- Negative Percent Agreement: 96.9% (2292/2365) (95% Cl: 96.1-97.5%)
- Overall Percent Agreement: 96.9% (2427/2504) (95% Cl: 96.2-97.5%)
- Prevalence: 5.6%
- SA:
- Positive Percent Agreement: 97.0% (577/595) (95% CI: 95.3-98.1%)
- Negative Percent Agreement: 92.1% (1759/1909) (95% Cl: 90.8-93.3%)
- Overall Percent Agreement: 93.3% (2336/2504) (95% Cl: 92.2-94.2%)
- Prevalence: 23.8%
Predicate Device(s): If the device was cleared using the 510(k) pathway, identify the Predicate Device(s) K/DEN number used to claim substantial equivalence and list them here in a comma separated list exactly as they appear in the text. List the primary predicate first in the list.
Roche Lightcycler MRSA, K091409
Reference Device(s): Identify the Reference Device(s) K/DEN number and list them here in a comma separated list exactly as they appear in the text.
Not Found
Predetermined Change Control Plan (PCCP) - All Relevant Information for the subject device only (e.g. presence / absence, what scope was granted / cleared under the PCCP, any restrictions, etc).
Not Found
§ 866.1640 Antimicrobial susceptibility test powder.
(a)
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.(b)
Classification. Class II (performance standards).
0
Image /page/0/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo is circular and contains the words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" around the perimeter. Inside the circle is an abstract symbol that resembles a stylized eagle or bird in flight.
Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
ROCHE MOLECULAR SYSTEMS, INC. WILK VON GUSTEDT, PH.D. SR. REGULATORY SPECIALIST II 4300 HACIENDA DRIVE PLEASANTON CA 94588-2722
December 17, 2014
Re: K142721
Trade/Device Name: cobas MRSA/SA Test Regulation Number: 21 CFR 866.1640 Regulation Name: Antimicrobial susceptibility test powder Regulatory Class: II Product Code: NOX, OOI Dated: September 22, 2014 Received: September 23, 2014
Dear Dr. von Gustedt:
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food. Drug. and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21. Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Parts 801 and 809); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
1
If you desire specific advice for your device on our labeling regulations (21 CFR Parts 801 and 809), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638 2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/Resourcesfor You/Industry/default.htm. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to
http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.
You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.
Sincerely yours.
Uwe Scherf -S for
Sally A. Hojvat. M.Sc., Ph.D. Director Division of Microbiology Devices Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health
Enclosure
2
Indications for Use
510(k) Number (if known) K142721
Device Name cobas® MRSA/SA Test
Indications for Use (Describe)
The cobas® MRSA/SA Test on the cobas® 4800 system, is a qualitative in vitro diagnostic real-time PCR assay, for the direct detection of methicillin-resistant Staphylococus aureus (MRSA) and S.aureus (SA) DNA from nasal swabs to aid in the prevention and control of MRSA and SA infections in healthcare settings. The cobas® MRSA/SA Test is not intended to diagnose, guide or monitor treatment for MRSA or SA infections, or provide results of susceptibility to methicillin. A negative result does not preclude MRSA/SA nasal colonization. Concomitant cultures are necessary to recover organisms for epidemiology typing or for further susceptibility testing.
Type of Use (Select one or both, as applicable)
X Prescription Use (Part 21 CFR 801 Subpart D)
_ Over-The-Counter Use (21 CFR 801 Subpart C)
PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON A SEPARATE PAGE IF NEEDED.
FOR FDA USE ONLY
Concurrence of Center for Devices and Radiological Health (CDRH) (Signature)
3
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4
510(k) Summary
| Submitter Name | Roche Molecular Systems, Inc. |
|---|---|
| Address | 4300 Hacienda Drive |
| Pleasanton, CA 94588-2722 | |
| Contact | Wilk von Gustedt |
| Phone: (925) 730-8046 | |
| FAX: (925) 225-0207 | |
| Date Prepared | September 18, 2014 |
| Proprietary Name | cobas® MRSA/SA Test |
| Common Name | MRSA/SA Test |
| Classification Name | Antimicrobial susceptibility test powder. (21 CFR 866.1640) |
| Real Time Nucleic Acid Amplification System (21 CFR 862.2570) | |
| Product Codes | NQX: System, Nucleic Acid amplification Test, DNA, Methicillin Resistant |
| Staphylococcus aureus, Direct Specimen | |
| OOI: Real Time Nucleic Acid Amplification System | |
| Predicate Devices | Roche Lightcycler MRSA, K091409 |
| Establishment Registration | Branchburg: 2243471 |
| Pleasanton: 3004141078 | |
| Indianapolis: 1823260 |
5
1. DEVICE DESCRIPTION
The Roche Molecular Systems (RMS) cobas® MRSA/SA Test utilizes real-time polymerase chain reaction (PCR) for the detection of Methicillin resistant Staphylococcus aureus (MRSA) and Staphylococcus aureus (SA) DNA from nasal swab specimens collected in MSwab medium to aid in the prevention and control of MRSA and SA infections in healthcare settings.
The cobas® MRSA/SA Test contains two major processes: (1) automated sample preparation to extract nucleic acids from the nasal swab specimens; (2) PCR amplification of target DNA sequences using MRSA and SA specific primers, and real-time detection of cleaved fluorescentlabeled MRSA and SA specific oligonucleotide detection probes. An Internal Control (IC), containing unrelated randomized DNA sequence, is added to all samples prior to automated sample preparation and is amplified and detected simultaneously with each sample to monitor the entire process.
The MSwab Collection, Transport and Preservation System (Copan Flock Technologies S.r.1.) is used for specimen collection, transportation and storage of specimen for the cobas MRSA/SA Test.
The cobas® MRSA/SA Test utilizes six reagent kits:
-
- cobas® 4800 MRSA/SA Amplification/Detection Kit
-
- cobas® 4800 MRSA/SA Controls and Cofactor Kit
-
- cobas® 4800 System Wash Buffer Kit
-
- cobas® 4800 System Lysis Kit 1
-
- cobas 4800 System Internal Control Kit 1
-
- cobas® 4800 System Sample Preparation Kit
6
1.1. Target Selection
The well-characterized Right Extremity (RE) junction between the Staphylococcus aureus orfX gene and SCCmec cassette carrying the mecA drug-resistant gene was chosen to be the target to specifically detect MRSA. The capsular polysaccharide enzyme CAP5N (CPE) gene was chosen as the target for Staphylococcus aureus identification. This gene is conserved in Staphylococcus aureus and present in both methicillin resistant and methicillin sensitive organisms. Internal Control (IC) DNA sequence is unique and unrelated to either MRSA or SA target sequences.
Test Principle 1.2.
Sample Preparation 1.1.1.
Sample preparation for the cobas® MRSA/SA Test is automated with the use of the cobas x 480 instrument. Organisms in nasal swab specimens collected in MSwab medium are lysed with chaotropic agent, proteinase K, and SDS reagents. Released nucleic acids, along with added Internal Control DNA, are bound by magnetic glass particles. They are washed and then eluted into a small volume of buffer. The instrument then takes an aliquot of the eluted material and sets up the PCR reaction with an activated Master Mix.
1.1.2. PCR Amplification and TaqMan® Detection
The PCR cycling steps and detection of target signal occurs in the cobas z 480 Analyzer. The Master Mix reagent contains primer pairs and probes for orfX (MRSA), CPE (SA) and IC targets. If the target nucleic acid sequences are present, amplification with the corresponding primers will occur by a thermostable DNA polymerase, generating PCR products (amplicons). These products are detected by specific TaqMan probes containing a fluorescent dye and a quencher. Normally, the quencher suppresses the fluorescence of the dye. However, if the PCR product is present, the probe hybridizes to the product and gets cleaved by the 5' to 3' nuclease activity of the polymerase. This reaction allows the fluorescence to be emitted from the dye, and the signal is recorded in real time during each PCR cycle by the cobas z 480 analyzer. The signal is interpreted by the cobas 4800 System Software and reported as final results.
7
cobas® 4800 System Description 1.3.
The cobas® 4800 System uses the cobas x 480 Instrument for sample preparation, and the cobas z 480 Analyzer for amplification and detection. Both the cobas x 480 Instrument and the cobas z 480 Analyzer are controlled by a computer workstation running the cobas® 4800 System Software.
The system hardware is unchanged from that originally approved for IVD use in PMA P100020 (cobas® HPV Test, April 19, 2011). The software version has been updated to software release 2.1 in order to support the expanded test menu. The updated software was cleared for other currently available tests on the cobas® 4800 System per Special 510(K) 140887.
INDICATIONS FOR USE 2.
The cobas® MRSA/SA Test on the cobas® 4800 system, is a qualitative in vitro diagnostic realtime PCR assay, for the direct detection of methicillin-resistant Staphylococcus aureus (MRSA) and S.aureus (SA) DNA from nasal swabs to aid in the prevention and control of MRSA and SA infections in healthcare settings. The cobas® MRSA/SA Test is not intended to diagnose, guide or monitor treatment for MRSA or SA infections, or provide results of susceptibility to methicillin. A negative result does not preclude MRSA/SA nasal colonization. Concomitant cultures are necessary to recover organisms for epidemiology typing or for further susceptibility testing.
TECHNOLOGICAL CHARACTERISTICS 3.
As indicated in Table 1, the RMS cobas® MRSA/SA Test has the same general intended use as the predicate device. The subject device is substantially equivalent from its technological characteristics to the currently legally marketed predicate device.
Differences reside in sample collection and preparation. The candidate test utilizes an automated extraction process while the predicate uses a manual process. However both devices are similar in the method used for extraction of nucleic acids from specimens, using glass beads together with Lysis buffer. The additional (SA) target detected by the cobas® MRSA/SA test uses the same technological methodology as used for detection of the MRSA target.
8
| | Submitted Device:
RMS cobas® MRSA/SA Test | Predicate Device:
Lightcycler® MRSA Advanced Test
K091409 |
|--------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Intended Use | The cobas® MRSA/SA Test on the
cobas® 4800 system, is a qualitative in
vitro diagnostic real-time PCR assay, for
the direct detection of methicillin-resistant
Staphylococcus aureus (MRSA) and
S.aureus (SA) DNA from nasal swabs to
aid in the prevention and control of MRSA
and SA infections in healthcare settings.
The cobas® MRSA/SA Test is not
intended to diagnose, guide or monitor
treatment for MRSA or SA infections, or
provide results of susceptibility to
methicillin. A negative result does not
preclude MRSA/SA nasal colonization.
Concomitant cultures are necessary to
recover organisms for epidemiology typing
or for further susceptibility testing. | The LightCycler® MRSA Advanced Test is
a qualitative in vitro diagnostic test for the
direct detection of nasal colonization with
methicillin-resistant (MRSA) to aid in the
prevention and control of MRSA infections
in healthcare settings. The test is
performed on the LightCycler® 2.0
Instrument with nasal swab specimens
from patients suspected of colonization,
uses swab extraction and mechanical lysis
for specimen preparation followed by
polymerase chain reaction (PCR) for the
amplification of MRSA DNA, and
fluorogenic target specific hybridization
probes for the detection of the amplified
DNA.
The LightCycler® MRSA Advanced Test is
not intended to diagnose, guide or monitor
treatment for MRSA infections.
Concomitant cultures are necessary to
recover organisms for epidemiology typing
or for further susceptibility testing. |
| Conditions for use | For prescription use | Same |
| Sample Types | Nasal swab | Same |
| Amplification Technology | Real-time PCR | Same |
| Detection Chemistry | paired target-specific hybridization probes
using Förster resonance energy transfer
(FRET) | Same |
| Controls used | Sample processing control (IC)
Positive and negative control | Same |
| Analyte Target | SCCmec cassette Right Extremity (RE)
junction of methicillin-resistant
Staphylococcus aureus (MRSA) | Same target region for MRSA detection |
Similarities and Differences between the cobas® MRSA/SA Test Table 1: and the Predicate Device
9
| | Submitted Device:
RMS cobas® MRSA/SA Test | Predicate Device:
Lightcycler® MRSA Advanced Test
K091409 | | | |
|---------------------------------|--------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------|--|--|--|
| Differences | | | | | |
| Sample Collection Devices | Copan MSwab Collection, Transport
and Preservation System | Liquid Stuart Swabs, Amies Gel with
Charcoal Swabs, Amies Gel without
Charcoal Swabs | | | |
| Analyte Target | wt Staphylococcus aureus (SA) | methicillin-resistant Staphylococcus
aureus (MRSA) only | | | |
| Sample Preparation
Procedure | Automated by cobas® x480 | Lysis of the nasal swab specimens is
performed by using the LightCycler®
Advanced Lysis Kit and the MagNA Lyser
Instrument. | | | |
| Result Analysis | Based on PCR cycle threshold analysis | Melting peak analysis | | | |
In summary, the intended use and technological characteristics of the cobas® MRSA/SA Test as compared to the predicate device do not raise any new types of safety or effectiveness questions and are substantially equivalent.
4. NON-CLINICAL PERFORMANCE EVALUATION
Analytical Sensitivity 4.1.
The analytical sensitivity (Limit of Detection or LOD) for the cobas® MRSA/SA Test was determined by analyzing 2 MRSA culture isolates and 1 SA culture isolate. Quantified cultures were diluted to 8-9 concentration levels into a simulated nasal swab background matrix to determine the LOD. All levels were analyzed using cobas® MRSA/SA Test with 3 unique lots of MRSA/SA specific reagents. The LOD of the test was determined as the lowest concentration exhibiting at least 95% positive rate for which all higher concentrations were greater than or equal to 95% positive rate.
The highest LOD among 3 reagent lots are shown in Table 2. The highest claimed LOD between the 2 MRSA strains tested was 700 CFU/swab and for SA it was 700 CFU/swab based on 95% positive rate.
10
| Isolate Name | Source ID | RE type | SCCmec
type | spa type | PFGE
type | MIC
value | LOD
(CFU/swab) |
|--------------|------------|---------|----------------|----------|--------------|--------------|-------------------|
| MRSA 10364 | NARSA 384 | 2 | IVa | t008 | USA300-0114 | 32 | 650 |
| MRSA 8065 | ATCC 43300 | 2 | II | t007 | Sac-15 | n/a | 700 |
| SA 10851 | NARSA 164 | n/a | n/a | t084 | n/a | n/a | 700 |
cobas® MRSA/SA Test Limit of Detection Table 2:
Genotype LOD verification 4.2.
The sensitivity of the cobas MRSA/SA Test was determined for 35 additional MRSA culture isolates and 5 additional SA culture isolates. The genotype LOD panel consisted of at least three concentrations per isolate in simulated nasal swab background matrix. The LOD was calculated as the lowest concentration level with ≥ 95 % positive rate for which all higher concentration levels show ≥ 95 % positive rate. A minimum of one lot of reagents was used for this study.
The genotype LOD study results are listed in Table 4. As shown in Table 3, the LOD is ranging from 175 to 750 CFU/swab for the 35 MRSA isolates tested. The cobas MRSA/SA Test detected the RE types 1, 2, 3, 4, 6, 9, 11, 14, 24 and 25. The cobas MRSA/SA Test detected MRSA SCCmec types I, II, III, IV, V, VI and VIII, as well as MRSA PFGE types USA 100 to 1000. Five SA isolates tested represent 5 different spa types, and the LOD is 175 CFU/swab for all isolates (Table 4).
11
| Isolate # | RE Type | SCCmec Type | spa Type | Cefoxitin MIC Value*
(μg/mL) | PFGE Type | LOD (CFU/Swab) |
|-----------|---------|-------------|----------|---------------------------------|-----------|----------------|
| 1 | 11 | new | t002 | ≥8 | Unknown | 485 |
| 2 | 6 | II | t242 | ≥8 | Unknown | 720 |
| 3 | 9/11 | new | t024 | ≥8 | Unknown | 175 |
| 4 | 14 | Unknown | Unknown | Unknown | Unknown | 700 |
| 5 | 25 | Unknown | t003 | ≥8 | Unknown | 175 |
| 6 | 6 | II | t216 | ≥8 | USA100 | 720 |
| 7 | 2 | IV | t008 | ≥8 | USA300 | 350 |
| 8 | 2 | II | t037 | ≥8 | USA200 | 700 |
| 9 | 2 | IV | t1578 | ≥8 | USA300 | 700 |
| 10 | 2 | II | t002 | ≥8 | USA100 | 720 |
| 11 | 2 | IV | t008 | ≥8 | USA800 | 750 |
| 12 | 2 | IV | t008 | ≥8 | USA300 | 266 |
| 13 | 2 | IV | t064 | ≥8 | USA500 | 260 |
| 14 | 2 | IV | t148 | ≥8 | USA700 | 700 |
| 15 | 2 | IV | t688 | ≥8 | USA800 | 271 |
| 16 | 2 | IV | t688 | ≥8 | USA300 | 700 |
| 17 | 2 | II | t042 | ≥8 | USA100 | 463 |
| 18 | 2 | II | t018 | ≥8 | USA200 | 350 |
| 19 | 2 | IV | t008 | ≥8 | USA300 | 410 |
| 20 | 2 | IV | t008 | ≥8 | USA300 | 175 |
| 21 | 2 | IV | t5576 | ≥8 | USA800 | 202 |
| 22 | 2 | II | t004 | ≥8 | USA600 | 350 |
| 23 | 2 | IV | t216 | ≥8 | USA1000 | 350 |
| 24 | 2 | IV | t064 | ≥8 | Iberian | 175 |
| 25 | 2 | II | t266 | ≥8 | USA600 | 700 |
| 26 | 2 | IV | t008 | ≥8 | USA300 | 700 |
| 27 | 2 | IV | t008 | ≥8 | USA300 | 350 |
| 28 | 2 | IV | t002 | ≥8 | USA800 | 350 |
| 29 | 3 | V | t242 | ≥8 | USA1000 | 350 |
| 30 | 24 | new | t476 | ≥8 | Unknown | 350 |
| 31 | 1 | I | t149 | ≥8 | Unknown | 175 |
| 32 | 3 | VIII | Unknown | ≥8 | Unknown | 700 |
| 33 | 4 | IV | Unknown | ≥8 | Unknown | 350 |
| 34 | 2 | III | t030 | ≥8 | Unknown | 700 |
| 35 | 25 | VI | Unknown | Unknown | Unknown | 175 |
Table 3: MRSA isolate LOD Results
*Isolates 1,2,5-10, 12-29, 31 and 34 have Cefoxitin MC values 3,11 and 32 have Cefoxitin
MC values of ≥16 µg/mL; isolate 33 has an Cefoxitin MC value of 12 µg/mL; isolate value of 8 µg/mL.
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| SA Isolate # | spa Type | LOD (CFU/Swab) |
|---|---|---|
| 1 | t238 | 175 |
| 2 | t018 | 175 |
| 3 | t008 | 175 |
| 4 | t002 | 175 |
| 5 | t088 | 175 |
Table 4: SA Isolates LOD Results
4.3. Geographical Inclusivity
In addition to 37 MRSA isolates and 6 SA isolates tested in analytical LOD and genotype LOD studies shown above, the inclusivity was also examined by testing a broad collection of MRSA and SA isolates from diverse geographical locations. Two hundred and eighty-one (281) MRSA from 16 European countries or regions, US, Japan and Australia and 85 SA isolates from diverse locations within US were tested. The MRSA collection contained MRSA isolates of different SCCmec types (I, II, III, IV, IVa, V, VI, VII, and new), and 71 spa types and cefoxitin MIC value from 6 to greater than 256. All 85 SA isolates sourced from the US contains 75 spa types were detected by the cobas® MRSA/SA Test. The geographical inclusivity study results for MRSA isolates are listed in Table 5. Of the two hundred eighty-one MRSA isolates, two hundred seventy-seven of the MRSA isolates were detected. The four MRSA isolates not detected by the cobas® MRSA/SA Test were sequenced, and the results suggested that the target regions contained sequences not recognized by the primers and probes in the cobas MRSA/SA Test. One of the four isolates was a mec ALGA251 (also known as mec C) strain.
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| Geographical Origin | Total Number of MRSA Isolates | Detected by cobas® MRSA/SA Test |
|---|---|---|
| England | 58 | 58 |
| Germany | 51 | 51 |
| Denmark | 37 | 36 |
| France | 33 | 31 |
| US | 20 | 20 |
| Spain | 20 | 20 |
| Switzerland | 18 | 18 |
| Japan | 15 | 15 |
| Sweden | 7 | 7 |
| Australia | 6 | 5 |
| Netherlands | 5 | 5 |
| Italy | 4 | 4 |
| Belgium | 3 | 3 |
| Scotland | 2 | 2 |
| Ireland | 1 | 1 |
| Norway | 1 | 1 |
| Total | 281 | 277 |
Geographical Coverage of the cobas® MRSA/SA Test for MRSA Isolates Table 5:
4.4. Precision
In-house precision study was conducted with 2 MRSA culture isolates and 1 SA culture isolate a concentrations below, near and above Limit of Detection (LOD) of the cobas® MRSA/SA Test. The study used three unique lots of cobas® MRSA/SA Test reagents and three instruments for a total of 36 runs over 12 days (3 runs per day). A description of the precision panels, the study results, and variance components are shown in Table 6. An analysis of the variance of the Ct values from valid tests was performed on positive panel members above LOD concentrations. Overall, most of the variation in the cobas® MRSA/SA Test was attributed to random factors (41.2% - 44.9%) with contribution from reagent lot, kit size and run/day of testing (Table 7). The overall CV% of Ct values for cobas® MRSA/SA Test was less than or equal to 1.3% indicating good reproducibility (Table 8).
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| Target | Target
Concentration | Result interpretation | | | Total
Sample
Tested | %Detect
ed | 2-sided
95% Lower
CL | 2-sided
95% Upper
CL |
|----------------------------------------------------|-------------------------|-----------------------|----|----|---------------------------|---------------|----------------------------|----------------------------|
| Negative | No analyte | 72 | 0 | 0 | 72 | 0.0% | 0.0% | 5.0% |
| MRSA
Culture
Isolate 10364
(NARSA 384) | 50 years of age (67.2%) and ranged in age from 18 to 101 (median age = 57). There were a total of 160 MRSA-positive and 660 SA-positive specimens.
Performance of the cobas® MRSA/SA Test Compared to Combined Direct 5.2.1.1. and Enrichment Culture (Reference Method)
The performance of the cobas® MRSA/SA test compared to combined direct and enrichment culture from 2500 evaluable results for MRSA, and from 2501 evaluable results for SA, is shown in Table 19.
The sensitivity and specificity for MRSA compared to combined direct and enrichment culture was 93.1% (149/160) and 97.5% (2281/2340), respectively; and the prevalence, PPV and NPV was 6.4%, 71.6% and 99.5%, respectively.
33
The sensitivity and specificity for SA compared to combined direct and enrichment culture was 93.9% (620/660) and 94.2% (1734/1841), respectively, and the prevalence, PPV and NPV was 26.4%, 85.3% and 97.7%, respectively.
| Direct and Enrichment Culture (Reference Method) | ||||||||
|---|---|---|---|---|---|---|---|---|
| MRSA | SA | |||||||
| Positive | Negative | Total | Positive | Negative | Total | |||
| cobas® | MRSA/SA | |||||||
| Test | Positive | 149 | 59 | 208 | 620 | 107 | 727 | |
| Negative | 11 | 2281 | 2292 | 40 | 1734 | 1774 | ||
| Total | 160 | 2340 | 2500 | 660 | 1841 | 2501 | ||
| MRSA | ||||||||
| Sensitivity: 93.1% (149/160) (95% CI: 88.1-96.1%) | ||||||||
| Specificity: 97.5% (2281/2340) (95% CI: 96.8-98.0%) | ||||||||
| Prevalence: 6.4% | ||||||||
| PPV: 71.6% | ||||||||
| NPV: 99.5% | ||||||||
| SA | ||||||||
| Sensitivity: 93.9% (620/660) (95% CI: 91.9-95.5%) | ||||||||
| Specificity: 94.2% (1734/1841) (95% CI: 93.0-95.2%) | ||||||||
| Prevalence: 26.4% | ||||||||
| PPV: 85.3% | ||||||||
| NPV: 97.7% |
Table 19: Comparison of Results from the cobas® MRSA/SA Test with Direct and Enrichment Culture (Reference Method)
Comparison of Results of the cobas® MRSA/SA Test with Direct Culture 5.2.1.2. Results of the cobas® MRSA/SA test were compared to direct culture from 2504 evaluable results is shown in Table 20.
The overall, positive and negative percent agreement of the cobas® MRSA/SA Test for MRSA compared to direct culture was 96.9% (2427/2504), 97.1% (135/139) and 96.9% (2292/2365); and the prevalence was 5.6%.
The overall, positive and negative percent agreement of the cobas® MRSA/SA Test for SA compared to direct culture was 93.3% (2336/2504), 97.0% (577/595) and 92.1% (1759/1909), respectively; and the prevalence was 23.8%.
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| Direct Culture | |||||||
|---|---|---|---|---|---|---|---|
| MRSA | SA | ||||||
| Positive | Negative | Total | Positive | Negative | Total | ||
| cobas® | Positive | 135 | 73 | 208 | 577 | 150 | 727 |
| MRSA/SA | Negative | 4 | 2292 | 2296 | 18 | 1759 | 1777 |
| Test | Total | 139 | 2365 | 2504 | 595 | 1909 | 2504 |
Table 20: Comparison of Results from the cobas® MRSA/SA Test with Direct Culture
MRSA
Positive Percent Agreement: 97.1% (135/139) (95% CI: 92.8-98.9%) Negative Percent Agreement: 96.9% (2292/2365) (95% Cl: 96.1-97.5%) Overall Percent Agreement: 96.9% (2427/2504) (95% Cl: 96.2-97.5%) Prevalence: 5.6%
SA Positive Percent Agreement: 97.0% (577/595) (95% CI: 95.3-98.1%) Negative Percent Agreement: 92.1% (1759/1909) (95% Cl: 90.8-93.3%) Overall Percent Agreement: 93.3% (2336/2504) (95% Cl: 92.2-94.2%) Prevalence: 23.8%
Discrepant Analysis of Discordant and Concordant Samples 5.2.1.3.
Discrepant analysis was performed on all discordant samples, and a random subset of concordant samples included as controls, between the cobas® MRSA/SA Test and combined direct and enrichment culture, using a second, FDA-cleared nucleic acid amplification test (NAAT) and a non-selective direct and enrichment culture.
There were a total of 70 specimens with MRSA discordant results (11 MRSA False-negative results and 59 MRSA False-positive results). Of the 11 MRSA False-negative specimens, five tested MRSA-negative by a second NAAT method and non-selective direct and enrichment culture. Of the 59 MRSA False-positive specimens, 20 tested MRSA-positive by a second NAAT method or non-selective direct and/or enrichment culture.
There were a total of 147 specimens with SA discordant results (40 SA False-negative results and 107 SA False-positive results). Of the 40 SA False-negative specimens, 31 tested SAnegative by a second NAAT method and non-selective direct and enrichment culture. Of the 107 SA False-positive specimens, 24 tested SA-positive by a second NAAT method or non-selective direct and/or enrichment culture.
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There were 74 randomly selected concordant samples included as controls in the discrepant analysis (25 MRSA-positive, 25 SA-negative and 24 SA-positive/MRSA-negative concordant samples). Of the 74 controls, all 25 MRSA-positive specimens tested MRSA-positive by a second NAAT method or non-selective direct and/or enrichment culture; all 25 SA-negative specimens tested SA-negative by a second NAAT method and non-selective direct and enrichment culture; and, of the 24 SA-positive specimens, 21 tested SA-positive by a second NAAT method or non-selective direct and/or enrichment culture, 1 tested MRSA-positive by nonselective enrichment culture, and two tested SA-negative by a second NAAT method and non-selective direct and enrichment culture.
5.3. Summary
Based on the clinical performance evaluation as documented in the reproducibility and clinical study, the cobas® MRSA/SA test was found to have a safety and effectiveness profile that is similar to the predicate device.
CONCLUSIONS 6.
A comparison of the intended use, technological characteristics, and the results of non-clinical and clinical performance studies support that the cobas® MRSA/SA Test is substantially equivalent to the predicate device.