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.

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.

AI/ML Overview

The provide text describes the acceptance criteria and study results for chromID™ MRSA agar, a chromogenic medium for the qualitative detection of methicillin-resistant Staphylococcus aureus (MRSA).

Here's an analysis of the provided information:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are implied by the reported performance data for sensitivity and specificity. The device is expected to perform accurately in detecting MRSA from various specimen types.

Metric	Acceptance Criteria (Implied)	Reported Device Performance (Blood Culture)
Sensitivity	High (close to 100%)	100.0% (215/215) [98.3% – 100]%
Specificity	High (close to 100%)	98.9% (641/648) [97.8% – 99.5]%

Note: The provided text primarily focuses on the clinical performance for blood cultures. While analytical studies are mentioned, specific numerical acceptance criteria for those were not explicitly stated beyond achieving "expected results" or specific growth/detection rates.

2. Sample Size Used for the Test Set and Data Provenance

Clinical Study Sample Size (Blood Culture): 863 positive blood culture specimens (demonstrating Gram-positive cocci) were initially analyzed. 187 cultures were removed due to low prevalence of the target or protocol deviations, resulting in a final evaluated sample size.
Data Provenance: The study was conducted at four clinical sites. The geographical location of these sites (e.g., country of origin) is not specified. The clinical study is described as having "analyzed" specimens, suggesting a retrospective or prospective observational design where samples were collected and then tested. The phrase "clinical trial" is used, implying a prospective collection for evaluation. The "Analytical Studies" also mention the use of well-characterized strains, which would be laboratory-based rather than from clinical patients.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

The text does not explicitly state the number of experts used to establish the ground truth.
It also does not specify the qualifications of these experts.

4. Adjudication Method for the Test Set

The text describes a reference method for establishing ground truth, which involves:
- Growth on Tryptic Soy agar with 5% sheep blood (BAP).
- Testing of colonies suggestive of Staphylococcus species by Gram stain, catalase, and latex agglutination.
- Staphylococcus aureus isolates further tested for resistance to Oxacillin by the Cefoxitin Screen test.
- All Cefoxitin-resistant colonies tested for the presence of the mecA gene by PCR and by VITEK® MS for species confirmation.
For discordant specimens in the blood culture clinical study, "Two false positives were confirmed as MRSA positive" and "Five false positives that grew green colonies were not identified as MRSA." This implies a form of adjudication or re-evaluation for discordant results, likely by further expert review or follow-up testing, though a formal "2+1" or "3+1" structure isn't explicitly detailed.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, If So, What Was the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance

No, an MRMC comparative effectiveness study was not done.
This device (chromID™ MRSA agar) is a culture medium, not an AI-assisted diagnostic tool. Therefore, the concept of "human readers improve with AI vs. without AI assistance" does not apply.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

Yes, a standalone performance was done, but it's important to clarify the context. The "device" here is the chromID™ MRSA agar medium itself. The performance evaluation measures the ability of this agar to correctly identify MRSA based on color change, which is then interpreted by a laboratory user (a manual interpretation of the agar plate).
The clinical performance data for sensitivity and specificity (100.0% and 98.9% respectively for blood cultures) represent the standalone performance of the chromID™ MRSA agar in classifying samples as MRSA positive or negative, compared to the defined reference method.

7. The Type of Ground Truth Used

The ground truth for the clinical studies was established using a multi-faceted reference method, which includes:
- Culture on Tryptic Soy agar with 5% sheep blood (BAP).
- Gram stain, catalase, and latex agglutination for presumptive identification.
- Oxacillin resistance testing by Cefoxitin Screen test.
- Molecular testing (PCR for mecA gene) for definitive confirmation of methicillin resistance.
- Species confirmation by VITEK® MS.
- This combination represents a robust "expert consensus" or "gold standard" laboratory method, incorporating phenotypic and genotypic characteristics.

8. The Sample Size for the Training Set

The document does not explicitly mention a "training set" in the context of machine learning or AI development. Since this is a chromogenic culture medium, its development likely involved iterative formulation and testing, rather than a distinct machine learning training set as typically understood.
The "Analytical Reactivity (Challenge)" and "Cross Reactivity (Analytical Specificity)" studies, using specific well-characterized strains (80 mecA MRSA strains, 5 mecC MRSA strains, and 71 non-MRSA strains), could be seen as part of the developmental testing that helps "train" the understanding of the medium's performance, but not in the AI sense.

9. How the Ground Truth for the Training Set Was Established

As a "training set" for an AI algorithm is not applicable, the question of its ground truth establishment is also not directly applicable in the AI context.
However, for the analytical studies involving known strains, the ground truth was established by prior characterization of these strains (e.g., they are known mecA MRSA strains, mecC MRSA strains, or specific non-MRSA species), likely through established microbiological and molecular methods.

Summary

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Image /page/0/Picture/1 description: The image shows the logo for the U.S. Department of Health and Human Services. The logo consists of a stylized depiction of an eagle or bird-like figure with three curved lines representing its wings or feathers. The logo is surrounded by the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" arranged in a circular fashion around the emblem.

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 (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,

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 :

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)

CONTINUE ON A SEPARATE PAGE IF NEEDED.

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Form Approved: OMB No, 0910-0120 Expiration Date: January 31, 2017 See PRA Statement below.

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

A. 510(k) Submission Information:

Submitter's Name:	bioMérieux, Inc.
Address:	595 Anglum RoadHazelwood, MO 63042
Contact Person:	Karen RussellStaff 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, ExcludingMueller Hinton Agar21 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:

Substantial Equivalence

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

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	DevicechromID™ MRSA Agar	Predicate deviceRemel Spectra™ MRSA (K092407)
Similarities
Intended Use	chromID™ MRSA agar is aselective and differentialchromogenic medium for :A. The qualitative detection ofnasal colonization of methicillin-resistant Staphylococcus aureus(MRSA), to aid in the preventionand control of MRSA inhealthcare settings. The test isperformed on anterior nares swabspecimens from patients andhealthcare workers to screen forMRSA colonization. chromID™MRSA when used to detect nasalcolonization is not intended todiagnose, guide, or monitortherapy for MRSA infections, orprovide results of susceptibility tomethicillin.B. The qualitative detection ofMRSA from skin and skinstructure infections. chromID™MRSA is indicated for use inconjunction with other laboratorytests and clinical data available toaid in the identification anddiagnosis of MRSA infections.Concomitant cultures for skin andskin structure infections arenecessary to recover organismsfor further microbiologicalsusceptibility testing orepidemiological typing. Anegative result does not precludeMRSA infection. chromID™MRSA is not intended to monitortreatment for MRSA infections, orprovide results ofsusceptibility to methicillin.C. The qualitative detection ofMRSA from positive bloodcultures demonstrating Gram-positive cocci on Gram stain.	Remel Spectra™ MRSA is aselective and differentialchromogenic medium recommendedfor use in the qualitative detection ofnasal colonization of methicillin-resistant Staphylococcus aureus(MRSA) to aid in the prevention andcontrol of MRSA in healthcaresettings. The test is performed withanterior nares swab specimens frompatients and healthcare workers toscreen for MRSA colonization.Spectra™ MRSA is not intended todiagnose MRSA infection or toguide or monitor treatment forinfections.Spectra™ MRSA is also intended foruse in the qualitative detection ofMRSA from positive blood culturesdemonstrating Gram-positive coccion Gram stain. Spectra™ MRSA isindicated for use in conjunction withother laboratory tests and clinicaldata available to the clinician as anaid in the detection of MRSA frompatient positive blood cultures.Spectra™ MRSA is not intended tomonitor treatment for MRSAinfections, or provide results ofsusceptibility to methicillin. Allpositive blood bottles should be sub-cultured for further microbiological/susceptibility testing.
	Device	Predicate device
	chromIDTM MRSA Agar	Remel SpectraTM MRSA (K092407)
	chromIDTM MRSA is indicatedfor use in conjunction with otherlaboratory tests and clinical dataavailable to aid in theidentification and diagnosis ofMRSA infections. Sub-culturingfor positive blood cultures arenecessary to recover organismsfor further microbiologicalsusceptibility testing orepidemiological typing. Anegative result does not precludeMRSA infection. chromIDTMMRSA is not intended to monitortreatment for MRSA infections,or provide results ofsusceptibility to methicillin.
Test method	Manual	Manual
Specimen	Anterior nares specimens (Directspecimens)Positive blood cultures	Anterior nares specimens (Directspecimens)Positive blood cultures
Test Principle	chromIDTM MRSA agar consistsof a rich nutritive base combiningdifferent peptones. It alsocontains a chromogenic substrateof α-glucosidase and acombination of several antibioticsincluding cefoxitin, which favorthe growth of MRSA includinghetero-resistant strains and thedirect detection of MRSA strainsby revealing α-glucosidaseactivity (patient registered): greencolonies.	Remel SpectraTM MRSA is anopaque medium, which uses a novelchromogen that yields a denim-bluecolor as a result of phosphataseactivity. This enzyme is present in allStaphylococcus aureus , includingMRSA. To allow the medium todifferentiate MRSA accurately, itcontains a combination ofantibacterial compounds designed toinhibit the growth of a wide varietyof competitor organisms.
	The selective mixture ofantibiotics inhibits most bacterianot belonging to the genusStaphylococcus , as well as yeasts.The α-glucosidase produced by S. aureus cleaves the chromogenicsubstrate, which gives a greencolor to the S. aureus coloniesgrowing on the medium. Sincethe cefoxitin has inhibited non-methicillin-resistant S. aureusstrains, only the methicillin-resistant S. aureus strains grow	Also included are compounds thatencourage the production of MRSApathogenicity marker, ensuringexpression of the phosphataseenzyme and so providing enhancedsensitivity and specificity.
	Device	Predicate device
	chromID™ MRSA Agarand 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.
IncubationConditions	24h at 35-37°C aerobicconditions	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.

Staphylococcus aureus	ATCC 29213
Staphylococcus aureus	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 CultureInformation	Blood CultureBottle Type	Sensitivityn/N [%](95% Score CI)	Specificityn/N [%](95% Score CI)
BacT/ALERT®(vs. BAP)	FA (FAN®Aerobic)	32/32 [100.0%](89.3 - 100%)	14/14 [100.0%](78.5 - 100%)
	FA (FAN® PlusAerobic)	22/22 [100.0%](85.1 - 100%)	10/10 [100.0%](72.3 - 100%)
	FN (FAN®Anaerobic)	31/31 [100.0%](89.0 - 100%)	5/5 [100.0%](56.6 - 100%)
	FN (FAN® PlusAnaerobic)	20/20 [100.0%](83.9 - 100%)	7/7 [100.0%](64.6 - 100%)
	SA (StandardAerobic)	23/23 [100.0%](85.7 - 100%)	162/164 [98.8%](95.7 - 99.7%)
	SN (StandardAnaerobic)	25/25 [100.0%](86.7 - 100%)	95/96 [99.0%](94.3 - 99.8%)
	SYSTEM(Combined)	153/153 [100.0%](97.6 - 100%)	293/296 [99.0%](97.1 - 99.7%)
BACTEC™(vs. BAP)	Plus Aerobic/F	30/30 [100%](88.7 - 100%)	222/225 [98.7%](96.2 - 99.6%)
	Lytic/10Anaerobic/F	32/32 [100%](89.3 - 100%)	126/127 [99.2%](95.7 - 99.9%)
	SYSTEM(Combined)	62/62 [100.0%](94.2 - 100%)	348/352 [98.9%](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).

Regulation Number and Section

§ 866.1700 Culture medium for antimicrobial susceptibility tests.

(a)
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.(b)
Classification. Class II (performance standards).