chromID MRSA

K162076 · bioMerieux, Inc. · JSO · Oct 25, 2016 · Microbiology

Device Facts

• Record ID: K162076
• Device Name: chromID MRSA
• Applicant: bioMerieux, Inc.
• Product Code: JSO · Microbiology
• Decision Date: Oct 25, 2016
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.1700
• Device Class: Class 2

Intended Use

chromID™ MRSA agar is a selective and differential chromogenic medium for: a. The qualitative detection of nasal colonization of methicillin-resistant Staphylococcus aureus (MRSA), to aid in the prevention and control of MRSA in healthcare settings. The test is performed on anterior nares swab specimens from patients and healthcare workers to screen for MRSA colonization. chromID™ MRSA when used to detect nasal colonization is not intended to diagnose, guide, or monitor therapy for MRSA infections, or provide results of susceptibility to methicillin. b. The qualitative detection of MRSA from skin and skin structure infections. chromID™ MRSA is indicated for use in conjunction with other laboratory tests and clinical data available to aid in the identification and diagnosis of MRSA infections. Concomitant cultures for skin and skin structure infections are necessary to recover organisms for further microbiological susceptibility testing, or epidemiological typing. A negative result does not preclude MRSA infection. chromID™ MRSA is not intended to monitor treatment for MRSA infections, or provide results of susceptibility to methicillin. c. The qualitative detection of MRSA from positive blood cultures demonstrating Gram-positive cocci on Gram stain. chromID™ MRSA is indicated for use in conjunction with other laboratory tests and clinical data available to aid in the identification and diagnosis of MRSA infections. Sub-culturing for positive blood cultures are necessary to recover organisms for further microbiological susceptibility testing or epidemiological typing. A negative result does not preclude MRSA infection. chromID™ MRSA is not intended to monitor treatment for MRSA infections, or provide results of susceptibility to methicillin.

Device Story

chromID™ MRSA agar is a selective/differential chromogenic medium for MRSA detection. Input: aliquot from positive blood culture bottle (Gram-positive cocci). Operation: antibiotic mixture inhibits non-Staphylococcus/yeast; chromogenic substrate cleavage by S. aureus produces green colonies. Output: visual identification of green colonies after 24-hour aerobic incubation at 35-37°C. Used in clinical microbiology laboratories by trained personnel. Results aid clinicians in identifying MRSA infections; requires sub-culturing for further susceptibility testing. Benefits: rapid, direct identification of MRSA from positive blood cultures.

Clinical Evidence

Clinical study evaluated 863 positive blood culture specimens. Compared to reference method (BAP + confirmatory testing), chromID MRSA demonstrated 100% sensitivity (215/215) and 98.9% specificity (641/648). Analytical studies included reproducibility (100% agreement), limit of detection (10-100 CFU/mL), cross-reactivity, and interference testing. Bench testing confirmed performance across various blood culture bottle types (BacT/ALERT and BACTEC).

Technological Characteristics

Selective/differential chromogenic agar medium. Contains nutritive base, peptones, antibiotic mixture (including cefoxitin), and α-glucosidase chromogenic substrate. Manual incubation at 35-37°C for 24 hours under aerobic conditions. No software or electronic components.

Indications for Use

Indicated for qualitative detection of MRSA nasal colonization in patients/healthcare workers, MRSA from skin/skin structure infections, and MRSA from positive blood cultures (Gram-positive cocci). Not for monitoring treatment or determining methicillin susceptibility.

Regulatory Classification

Identification

A culture medium for antimicrobial susceptibility tests is a device intended for medical purposes that consists of any medium capable of supporting the growth of many of the bacterial pathogens that are subject to antimicrobial susceptibility tests. The medium should be free of components known to be antagonistic to the common agents for which susceptibility tests are performed in the treatment of disease.

Predicate Devices

• Remel Spectra™ MRSA (K092407)

Submission Summary (Full Text)

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Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002

October 25, 2016

BIOMERIEUX, INC. KAREN RUSSELL STAFF REGULATORY AFFAIRS SPECIALIST 595 ANGLUM ROAD HAZELWOOD MO 63042

Re: K162076

Trade/Device Name: chromID MRSA Regulation Number: 21 CFR 866.1700 Regulation Name: Culture medium for antimicrobial susceptibility tests Regulatory Class: II Product Code: JSO Dated: July 26, 2016 Received: July 29, 2016

Dear Ms. Russell:

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.

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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 [phone] or [phone] 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 [phone] or [phone] or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.

Sincerely yours,

# Ribhi Shawar -S

For Uwe Scherf, M.Sc., Ph.D. Director Division of Microbiology Devices Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health

Enclosure

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# Indications for Use

510(k) Number (if known) K162076

Device Name chromID™ MRSA agar

#### Indications for Use (Describe)

chromID™ MRSA agar is a selective and differential chromogenic medium for :

A. The qualitative detection of nasal colonization of methicillin-resistant Staphylococcus aureus (MRSA), to aid in the prevention and control of MRSA in healthcare settings. The test is performed on anterior nares swab specimens from patients and healthcare workers to screen for MRSA colonization. chromID™ MRSA when used to detect nasal colonization is not intended to diagnose, guide, or monitor therapy for MRSA infections, or provide results of susceptibility to methicillin.

B. The qualitative detection of MRSA from skin structure infections. chromID™ MRSA is indicated for use in conjunction with other laboratory tests and clinical data available to aid in the identification and diagnosis of MRSA infections. Concomitant cultures for skin structure infections are necessary to recover organisms for further microbiological susceptibility testing or epidemiological typing. A negative result does not preclude MRSA infection. chromID™ MRSA is not intended to monitor treatment for MRSA infections, or provide results of susceptibility to methicillin.

C. The qualitative detection of MRSA from positive blood cultures demonstrating Gram-positive cocci on Gram stain. chromID™ MRSA is indicated for use in conjunction with other laboratory tests and clinical data available to aid in the identification and diagnosis of MRSA infections. Sub-culturing for positive blood cultures are necessary to recover organisms for further microbiological susceptibility testing or epidemiological typing. A negative result does not preclude, MRSA infection. chromID™ MRSA is not intended to monitor treatment for MRSA infections, or provide results of susceptibility to methicillin.

| 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)

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# chromID™ MRSA Agar: 032. 510(k) Summary

#### A. 510(k) Submission Information:

| Submitter's Name: | bioMérieux, Inc. |
|----------------------|-------------------------------------------------------------------------------------------------------|
| Address: | 595 Anglum Road<br>Hazelwood, MO 63042 |
| Contact Person: | Karen Russell<br>Staff Regulatory Affairs Specialist |
| Phone Number: | 314-731-8639 |
| Fax Number: | 314-731-8689 |
| Date of Preparation: | July 26, 2016 |
| B. Device Name: | |
| Formal/Trade Name: | chromIDTM MRSA agar |
| Classification Name: | Culture Media, Antimicrobial Susceptibility Test, Excluding<br>Mueller Hinton Agar<br>21 CFR 866.1700 |
| Product Code | JSO |
| Common Name: | Culture media |
| | C. Predicate Device: Remel Spectra MRSA (K092407) |

# D. 510(k) Summary:

Intended Use:

chromID™ MRSA agar is a selective and differential chromogenic medium for :

A. The qualitative detection of nasal colonization of methicillin-resistant Staphylococcus aureus (MRSA), to aid in the prevention and control of MRSA in healthcare settings. The test is performed on anterior nares swab specimens from patients and healthcare workers to screen for MRSA colonization. chromIDTM MRSA when used to detect nasal colonization is not intended to diagnose, guide, or monitor therapy for MRSA infections, or provide results of susceptibility to methicillin.

B. The qualitative detection of MRSA from skin and skin structure infections. chromID™ MRSA is indicated for use in conjunction with other laboratory tests and clinical data

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available to aid in the identification and diagnosis of MRSA infections. Concomitant cultures for skin and skin structure infections are necessary to recover organisms for further microbiological susceptibility testing or epidemiological typing.

A negative result does not preclude MRSA infection. chromID™ MRSA is not intended to monitor treatment for MRSA infections, or provide results of susceptibility to methicillin.

C. The qualitative detection of MRSA from positive blood cultures demonstrating Grampositive cocci on Gram stain.

chromID™ MRSA is indicated for use in conjunction with other laboratory tests and clinical data available to aid in the identification and diagnosis of MRSA infections. Subculturing for positive blood cultures are necessary to recover organisms for further microbiological susceptibility testing or epidemiological typing.

A negative result does not preclude MRSA infection. chromID™ MRSA is not intended to monitor treatment for MRSA infections, or provide results of susceptibility to methicillin.

#### Indications for Use:

See Intended Use Statement.

# Device Description:

chromID™ MRSA agar consists of a rich nutritive base combining different peptones. It also contains a chromogenic substrate of a-glucosidase and a combination of several antibiotics, including cefoxitin, which favor the growth of MRSA including heteroresistant strains and the direct detection of MRSA strains by revealing a-glucosidase activity (patent registered), green colonies. The selective mixture of antibiotics inhibits most bacteria not belonging to the genus Staphylococcus, as well as yeasts. The MRSA strains are identified by the presence of green colonies that result from the chromogen incorporated in the medium. The chromogen targets the a-glucosidase activity of S. aureus. The a-glucosidase produced by S. aureus cleaves the chromogenic substrate, which gives a green color to the S. aureus colonies growing on the medium.

#### Substantial Equivalence

The similarities of chromID™ MRSA agar when compared to the predicate device are described in the following table.

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| | Device<br>chromID™ MRSA Agar | Predicate device<br>Remel Spectra™ MRSA (K092407) |
|--------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Similarities | | |
| Intended Use | chromID™ MRSA agar is a<br>selective and differential<br>chromogenic medium for :<br><br>A. The qualitative detection of<br>nasal colonization of methicillin-<br>resistant <i>Staphylococcus aureus</i><br>(MRSA), to aid in the prevention<br>and control of MRSA in<br>healthcare settings. The test is<br>performed on anterior nares swab<br>specimens from patients and<br>healthcare workers to screen for<br>MRSA colonization. chromID™<br>MRSA when used to detect nasal<br>colonization is not intended to<br>diagnose, guide, or monitor<br>therapy for MRSA infections, or<br>provide results of susceptibility to<br>methicillin.<br><br>B. The qualitative detection of<br>MRSA from skin and skin<br>structure infections. chromID™<br>MRSA is indicated for use in<br>conjunction with other laboratory<br>tests and clinical data available to<br>aid in the identification and<br>diagnosis of MRSA infections.<br>Concomitant cultures for skin and<br>skin structure infections are<br>necessary to recover organisms<br>for further microbiological<br>susceptibility testing or<br>epidemiological typing. A<br>negative result does not preclude<br>MRSA infection. chromID™<br>MRSA is not intended to monitor<br>treatment for MRSA infections, or<br>provide results of<br>susceptibility to methicillin.<br><br>C. The qualitative detection of<br>MRSA from positive blood<br>cultures demonstrating Gram-<br>positive cocci on Gram stain. | Remel Spectra™ MRSA is a<br>selective and differential<br>chromogenic medium recommended<br>for use in the qualitative detection of<br>nasal colonization of methicillin-<br>resistant <i>Staphylococcus aureus</i><br>(MRSA) to aid in the prevention and<br>control of MRSA in healthcare<br>settings. The test is performed with<br>anterior nares swab specimens from<br>patients and healthcare workers to<br>screen for MRSA colonization.<br>Spectra™ MRSA is not intended to<br>diagnose MRSA infection or to<br>guide or monitor treatment for<br>infections.<br><br>Spectra™ MRSA is also intended for<br>use in the qualitative detection of<br>MRSA from positive blood cultures<br>demonstrating Gram-positive cocci<br>on Gram stain. Spectra™ MRSA is<br>indicated for use in conjunction with<br>other laboratory tests and clinical<br>data available to the clinician as an<br>aid in the detection of MRSA from<br>patient positive blood cultures.<br><br>Spectra™ MRSA is not intended to<br>monitor treatment for MRSA<br>infections, or provide results of<br>susceptibility to methicillin. All<br>positive blood bottles should be sub-<br>cultured for further microbiological/<br>susceptibility testing. |
| | Device | Predicate device |
| | chromIDTM MRSA Agar | Remel SpectraTM MRSA (K092407) |
| | chromIDTM MRSA is indicated<br>for use in conjunction with other<br>laboratory tests and clinical data<br>available to aid in the<br>identification and diagnosis of<br>MRSA infections. Sub-culturing<br>for positive blood cultures are<br>necessary to recover organisms<br>for further microbiological<br>susceptibility testing or<br>epidemiological typing. A<br>negative result does not preclude<br>MRSA infection. chromIDTM<br>MRSA is not intended to monitor<br>treatment for MRSA infections,<br>or provide results of<br>susceptibility to methicillin. | |
| Test method | Manual | Manual |
| Specimen | Anterior nares specimens (Direct<br>specimens)<br>Positive blood cultures | Anterior nares specimens (Direct<br>specimens)<br>Positive blood cultures |
| Test Principle | chromIDTM MRSA agar consists<br>of a rich nutritive base combining<br>different peptones. It also<br>contains a chromogenic substrate<br>of α-glucosidase and a<br>combination of several antibiotics<br>including cefoxitin, which favor<br>the growth of MRSA including<br>hetero-resistant strains and the<br>direct detection of MRSA strains<br>by revealing α-glucosidase<br>activity (patient registered): green<br>colonies. | Remel SpectraTM MRSA is an<br>opaque medium, which uses a novel<br>chromogen that yields a denim-blue<br>color as a result of phosphatase<br>activity. This enzyme is present in all<br><i>Staphylococcus aureus</i> , including<br>MRSA. To allow the medium to<br>differentiate MRSA accurately, it<br>contains a combination of<br>antibacterial compounds designed to<br>inhibit the growth of a wide variety<br>of competitor organisms. |
| | The selective mixture of<br>antibiotics inhibits most bacteria<br>not belonging to the genus<br><i>Staphylococcus</i> , as well as yeasts.<br>The α-glucosidase produced by <i>S. aureus</i> cleaves the chromogenic<br>substrate, which gives a green<br>color to the <i>S. aureus</i> colonies<br>growing on the medium. Since<br>the cefoxitin has inhibited non-<br>methicillin-resistant <i>S. aureus</i><br>strains, only the methicillin-<br>resistant <i>S. aureus</i> strains grow | Also included are compounds that<br>encourage the production of MRSA<br>pathogenicity marker, ensuring<br>expression of the phosphatase<br>enzyme and so providing enhanced<br>sensitivity and specificity. |
| | Device | Predicate device |
| | chromID™ MRSA Agar<br>and turn green on the media. | Remel Spectra™ MRSA (K092407) |
| Differences | | |
| Interpreting results | The α-glucosidase produced by S. aureus cleaves the chromogenic substrate, which produces a green color to the S. aureus colonies growing on the medium. Any shade of green should be interpreted as a positive result. | After 24 hours incubation, MRSA will appear as small to medium denim blue colonies against a white background. The colonies are typically smaller than on non-selective media. Other organisms (non-MRSA) will exhibit marked inhibition or produce white colonies. If after 24 hours incubation no denim blue colonies are observed, the specimen is considered negative and plates should be discarded. |
| Incubation<br>Conditions | 24h at 35-37°C aerobic<br>conditions | 24h at 35-37°C ambient air |
| Specimen | Skin and skin structure specimens | Not applicable |

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Both devices incorporate selective agents in the agar to inhibit most bacteria not belonging to the genus Staphylococcus, as well as yeasts. Both media are selective for methicillin-resistant Staphylococcus and contain a chromogenic substrate that turns a specific color with growth of Staphylococcus aureus colonies. The differences in the two media are the selective agents and the targeted enzyme / chromogen combination resulting in the color of the S. aureus colonies.

# Performance Characteristics

# Analytical Studies

The following studies were conducted as part of K151688: Recovery (Limit of Detection), Analytical Reactivity (Challenge), Cross Reactivity (Analytical Specificity), Mixed Infection, Incubation, Expression of Resistance, and Interference Substances. These studies are also summarized below.

Reproducibility – Reproducibility of the chromID™ MRSA agar was evaluated with a set of ten well-characterized Staphylococcus aureus organisms, including both mecA positive and mecA negative isolates. These organisms were tested in triplicate each day at 1x103 CFU/mL for five days at three clinical trial sites. Expected results were obtained 100% of the 450 times tested.

Quality Control - Two quality control organisms were tested at each study site by chromIDTM MRSA on each day of testing.

| <i>Staphylococcus aureus</i> | ATCC 29213 |
|------------------------------|------------|
| <i>Staphylococcus aureus</i> | ATCC 43300 |

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The results for chromID™ MRSA agar QC were 100% correct for of the 297 times tested.

Recovery (Limit of Detection) - At 24 hours incubation time, the lowest concentration of MRSA organisms demonstrating growth with a positive result was 10 CFU/mL for one MRSA strain (ATCC® 43300) and 10° CFU/mL for the second MRSA strain (CDC Mu3-BR).

Analytical Reactivity (Challenge) - A challenge set composed of 80 mecA MRSA strains and 5 mecC MRSA strains was inoculated on the chromID™ MRSA agar with an inoculum equivalent to 10° CFU/mL. After 24 hours of incubation, 58/80 mecA MRSA strains and 4/5 mecC MRSA strains were detected on the chromID™ MRSA agar.

Cross Reactivity (Analytical Specificity) - To evaluate the analytical specificity of the chromID™ MRSA media, 71 non-MRSA strains representing bacterial and fungal species were inoculated onto chromID™ MRSA medium at a high inoculum level (10° CFU/mL). After 24 hours of incubation, forty-four strains did not grow and twenty strains grew colonies without green pigment. Green colonies (cross reactivity) were observed for three Klebsiella pneumoniae (KPC) strains, two Staphylococcus sciuri (oxacillin resistant) strains, one Enterobacter cloacae (KPC) strain, and one Staphylococcus pseudintermedius (oxacillin resistant) strain.

Mixed Infection - 10 MRSA strains at an organism concentration of 103 CFU/mL were inoculated alone and in association with 3 non-targeted strains at an organism concentration of 10°, 10°, or 10°CFU/ml. MRSA was still detected on chromID MRSA in the presence of high levels of non-target organisms.

Interfering Substances - For blood culture specimens tested in the presence of hemoglobin, triglyceride, conjugated and non-conjugated bilirubin, y-globulin, and sodium polyanethol sulfonate, all the MRSA strains were recovered. For blood culture bottles, there was no negative effect on the growth of MRSA strains on chromID MRSA. The bottles tested in the study included BacT/ALERT® aerobic FA. FA Plus, SA and anaerobic FN, FN Plus, SN and BacTEC™ aerobic Standard, Plus, Peds Plus and anaerobic Standard, Plus and Lytic.

Incubation - The incubation times required for three MRSA strains, at an organism concentration of 10 CFU/mL, to produce positive chromID™ MRSA results was 20 hours for two strains and 27 hours for one strain.

Expression of Resistance - Twenty eight well-characterized S. aureus (10 MRSA low level methicillin-resistant, 10 high level methicillin-resistant, 5 BORSA, and 3 MSSA strains) were evaluated with chromID™ MRSA. All low level and high level methicillinresistant strains were detected at an inoculum ≥ 10° CFU/mL. At lower concentrations some strains can give colorless colonies after 24 hours of incubation.

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# Clinical studies

chromID™ MRSA was evaluated at four clinical sites. chromID™ MRSA performance was determined by the presence or absence of green colonies. All green colonies were tested by Gram stain, catalase and latex agglutination, and Staphylococcus aureus colonies were tested for resistance to oxacillin by the Cefoxitin Screen test. All green colonies were also tested for the presence of the mecA gene by PCR, and species identification was confirmed by VITEK® MS.

Positive results were defined for chromID™ MRSA as the growth of green colonies. All other results, including the growth of white colonies and no growth, were considered negative.

Every sample was also tested by the reference method, which included growth on Tryptic Soy agar with 5% sheep blood (BAP). Colonies suggestive of Staphylococcus species were tested by Gram stain, catalase and latex agglutination. Staphylococcus aureus isolates were further tested for resistance to Oxacillin by the Cefoxitin Screen test. All colonies resistant to Oxacillin by the Cefoxitin Screen test were tested for the presence of the mecA gene by PCR and by VITEK® MS for species confirmation.

Positive results for BAP were defined as growth of Cefoxitin resistant Staphylococcus aureus present in the media up to 48 hours. All other results, including the growth of Cefoxitin susceptible Staphylococcus aureus, growth of other species and no growth, were considered negative.

| Blood Culture<br>Information | Blood Culture<br>Bottle Type | Sensitivity<br>n/N [%]<br>(95% Score CI) | Specificity<br>n/N [%]<br>(95% Score CI) |
|------------------------------|------------------------------|------------------------------------------|------------------------------------------|
| BacT/ALERT®<br>(vs. BAP) | FA (FAN®<br>Aerobic) | 32/32 [100.0%]<br>(89.3 - 100%) | 14/14 [100.0%]<br>(78.5 - 100%) |
| | FA (FAN® Plus<br>Aerobic) | 22/22 [100.0%]<br>(85.1 - 100%) | 10/10 [100.0%]<br>(72.3 - 100%) |
| | FN (FAN®<br>Anaerobic) | 31/31 [100.0%]<br>(89.0 - 100%) | 5/5 [100.0%]<br>(56.6 - 100%) |
| | FN (FAN® Plus<br>Anaerobic) | 20/20 [100.0%]<br>(83.9 - 100%) | 7/7 [100.0%]<br>(64.6 - 100%) |
| | SA (Standard<br>Aerobic) | 23/23 [100.0%]<br>(85.7 - 100%) | 162/164 [98.8%]<br>(95.7 - 99.7%) |
| | SN (Standard<br>Anaerobic) | 25/25 [100.0%]<br>(86.7 - 100%) | 95/96 [99.0%]<br>(94.3 - 99.8%) |
| | SYSTEM<br>(Combined) | 153/153 [100.0%]<br>(97.6 - 100%) | 293/296 [99.0%]<br>(97.1 - 99.7%) |
| BACTEC™<br>(vs. BAP) | Plus Aerobic/F | 30/30 [100%]<br>(88.7 - 100%) | 222/225 [98.7%]<br>(96.2 - 99.6%) |
| | Lytic/10<br>Anaerobic/F | 32/32 [100%]<br>(89.3 - 100%) | 126/127 [99.2%]<br>(95.7 - 99.9%) |
| | SYSTEM<br>(Combined) | 62/62 [100.0%]<br>(94.2 - 100%) | 348/352 [98.9%]<br>(97.1 - 99.6%) |

Blood Culture Bottle-System Type Performance Summary

A total of 863 positive blood culture specimens (demonstrating Gram-positive cocci) were analyzed during the clinical trial. One hundred eighty-seven cultures were removed

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due to low prevalence of target (in specific blood culture bottle type) and protocol deviations.

In the clinical study, MRSA was identified in 215 positive blood cultures by the reference method and 222 positive blood cultures by chromID™ MRSA (at 24 hours). Seven discordant specimens (MRSA positive result by chromID™: MRSA negative result by reference method) were observed. Two false positives were confirmed as MRSA positive. Five false positives that grew green colonies were not identified as MRSA as per latex agglutination and Cefoxitin screen results.

| chromID™ MRSA (24 hours) versus BAP Reference Method (48 | | |
|----------------------------------------------------------|------------------|-----------------|
| | Performance | 2-sided 95% CI |
| Sensitivity | 100.0% (215/215) | [98.3% – 100]% |
| Specificity | 98.9% (641/648) | [97.8% – 99.5]% |

chromID™ MRSA Clinical Performance Data hours) ch

The prevalence of MRSA detected by BAP plus confirmatory testing for MRSA was 24.9% (215/863), and the prevalence detected by chromID™ MRSA at 24 hours was 25.7% (222/863).