chromID™ MRSA agar is a selective and differential chromogenic medium for the qualitative detection of nasal colonization by methicillin-resistant S. aureus (MRSA) to aid in the prevention and control of MRSA infections in healthcare settings. The test is performed on anterior nares swab specimens from patients and healthcare workers to screen for MRSA colonization. chromID™ MRSA agar is not intended to diagnose MRSA infection nor to guide or monitor treatment for infections.

Device Description

chromID™ MRSA agar is a selective and differential chromogenic medium for the qualitative detection of MRSA from anterior nares swab specimens.

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, which favor the growth of MRSA including hetero-resistant strains. The antibiotics include: cefoxitin (4 mg/l), aztreonam (64 mg/l), and amphotericin B (3 mg/l). 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-qlucosidase activity of S. aureus. The a-ducosidase produced by S. aureus cleaves the chromogenic substrate, which gives a green color to the S. aureus colonies growing on the medium. This chromogen is identified as "Green a-glucoside" (5-Bromo-4-chloro-3-indoxyl-N-methyl-α-D-glucoside) (patent registered).

AI/ML Overview

Table of Acceptance Criteria and Reported Device Performance:

Method Comparison	Acceptance Criteria (Stated)	chromID™ MRSA Reported Performance (95% CI)
cMRSA	(Not explicitly stated as criteria in this document section, but implied by clinical performance demonstration)	94.7% (304/321) [91.7 – 96.9%]
TSAB	(Not explicitly stated)	91.6% (294/321) [88.0 – 94.4%]
cMRSA vs. Latex Agglutination	(Not explicitly stated)	96.3% (309/321) [93.6 – 98.1%]
cMRSA vs. Cefoxitin Screen	(Not explicitly stated)	96.3% (309/321) [93.6 – 98.1%]
cMRSA vs. mecA PCR	(Not explicitly stated)	100.0% (321/321) [98.9 – 100%]
Non-MRSA (across all methods)	(Not explicitly stated)	Ranging from 97.9% to 100.0% (918/938 to 938/938)
Overall Agreement	(Not explicitly stated)	98.6% (1242/1259) at 24h

Note: The document states "Clinical studies were performed and demonstrate acceptable performance of chromID™ MRSA," but specific pre-defined acceptance criteria values are not explicitly listed in this excerpt.

Sample Size Used for the Test Set and Data Provenance:
- Test Set Sample Size:
  - MRSA positive samples: 321
  - Non-MRSA samples: 938
  - Total samples in clinical performance comparison: 1259 (321 + 938)
- Data Provenance: Not explicitly stated in the provided text (e.g., country of origin, retrospective or prospective).
Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
- The document implies that "conventional methods including the identification and susceptibility testing" and other specific molecular/phenotypic tests (Latex Agglutination, Cefoxitin Screen, mecA PCR) were used to establish ground truth. However, the exact number of experts involved in analyzing these conventional methods or establishing the final ground truth, nor their specific qualifications, are explicitly mentioned.
Adjudication Method for the Test Set:
- The document does not explicitly describe an adjudication method for conflicting results. The "Performance is based on the number of true positives detected from either medium during the trial (true positives = number of samples positive by TSAB + number of samples that are false negative by TSAB and positive by chromID™ MRSA)" suggests a hierarchical or combined approach to defining true positives, but not a formal expert adjudication process.
Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
- No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study focusing on how much human readers improve with AI vs. without AI assistance was not mentioned. This device is a diagnostic culture medium, not an AI-assisted diagnostic tool for human readers.
Standalone Performance Study:
- Yes, the clinical performance data presented (e.g., "Clinical Performance Compared to Conventional Methods after 24 h Incubation") represents the standalone performance of the chromID™ MRSA agar against established conventional laboratory methods. The device itself (the agar medium) is the 'algorithm' in this context.
Type of Ground Truth Used:
- The ground truth was established using a combination of "conventional methods including the identification and susceptibility testing" for S. aureus, and specific tests like TSAB (Trypticase Soy Agar with 5% Sheep Blood), Latex Agglutination, Cefoxitin Screen, and mecA PCR. This indicates a laboratory-based, microbiology ground truth (culture, susceptibility testing, molecular diagnostics).
Sample Size for the Training Set:
- The document does not provide details on a separate "training set" as this is a traditional diagnostic medium, not a machine learning algorithm that typically requires a distinct training phase with labeled data. The clinical performance data appears to be from the validation/test set.
How the Ground Truth for the Training Set Was Established:
- As no separate training set is explicitly mentioned or relevant for this type of device (a diagnostic culture medium), there is no information on how its ground truth would have been established.

Summary

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JUL 1 7 2009

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chromID ™ MRSA Agar Traditional 510(k) Submission

SECTION 2: EXECUTIVE SUMMARY

Intended Use:

Device Description:

chromID™ MRSA agar is a selective and differential chromogenic medium for the qualitative detection of MRSA from anterior nares swab specimens.

Device Comparison Table:

Item	DevicechromIDTM MRSA Agar	PredicateBBLTM CHROMagarTM MRSA
Similarities
Intended Use	chromIDTM MRSA agar is aselective and differentialchromogenic medium for thequalitative detection of nasalcolonization by methicillin-resistant S. aureus (MRSA) to aidin the prevention and control ofMRSA infections in healthcaresettings. The test is performed onanterior nares swab specimensfrom patients and healthcareworkers to screen for MRSAcolonization. chromIDTM MRSAagar is not intended to diagnoseMRSA infection nor to guide ormonitor treatment for infections.	BBLTM CHROMagarTM MRSA is a selectiveand differential medium for the qualitativedirect detection of nasal colonization bymethicillin resistant Staphylococcus aureus(MRSA) to aid in the prevention and controlof MRSA infections in healthcare settings.The test is performed on anterior naresswab specimens from patients andhealthcare workers to screen for MRSAcolonization. BBLTM CHROMagarTM MRSAis not intended to diagnose MRSA infectionnor to guide or monitor treatment forinfections.
Test method	Manual	Manual
Inoculum	Direct Specimen	Direct Specimen
Specimen	Anterior nares specimens	Anterior nares specimens

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

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chromID ™ MRSA Agar

IFUX

Traditional 510(k) Submission

Item	DevicechromID™ MRSA Agar	PredicateBBL™ CHROMagar™ MRSA
Differences
Detection method	chromID™ MRSA contains achromogenic substrate and acombination of severalantibiotics including cefoxitin.The chromogenic substrateprovides for the direct detectionof MRSA by revealing α-glucosidase activity whichproduces green colonies(patent registered).	BBL™ CHROMagar™ MRSA containsspecific chromogenic substrates andcefoxitin. MRSA strains growing in thepresence of these substrates willproduce mauve-colored coloniesresulting from hydrolysis of thechromogenic substrate.
IncubationConditions	24h at 35-37°C in aerobicconditions	24-48 h in 33-37°C in aerobic conditions

Discussion:

Both devices have similar Intended Use statements. The technological characteristics are similar but not identical. Both devices, chromID™ MRSA agar and BBL™ CHROMagar™ MRSA, are chromogenic media incorporated with cefoxitin for the direct detection of methicillin resistant Staphylococcus aureus from anterior nares specimens. Both devices incorporate selective agents in the agar to most bacteria not belonging to the genus Staphylococcus, as well as yeasts. chromID™ MRSA agar contains chromogenic substrates that reveal a-glucosidase activity of MRSA strains and produce green colonies. BBL™ CHROMagar™ MRSA contains specific chromogenic substrates. MRSA strains growing in the presence of these substrates will produce mauve-colored colonies resulting from hydrolysis of the chromogenic substrate

The safety and effectiveness of the chromID™ MRSA agar is not impacted by the technology differences. The chromID™ MRSA agar utilizes nutrient agar medium that contains selective and differential agents and is very similar to the BBL™ CHROMagar™ MRSA agar. The significant technological difference between the two media is the type of chromogenic substrate incorporated in the media to indicate the presence of MRSA colonies.

Clinical studies were performed and demonstrate acceptable performance of chromID™ MRSA. The overall agreement for detection of MRSA and non-MRSA by chromiD™ MRSA compared to conventional methods including the identification and susceptibility testing was 98.6% (12421259) at 24 h. Performance comparisons to confirmed MRSA and non-MRSA strains can be found in the following table:

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------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ﻜ --------------------------------------------------------------------------------------------------------------------------------------------------------------------------chromID ™ MRSA Agar

Traditional 510(k) Submission

Methods	MRSA	Non-MRSA
cMRSA	94.7% (304/321)95% CI = 91.7 – 96.9%	100.0% (938/938)95% CI = 99.6 – 100%
TSAB	91.6% (294/321)95% CI = 88.0 – 94.4%	100.0% (938/938)95% CI = 99.6 – 100%
cMRSA vs. Latex Agglutination	96.3% (309/321)95% CI = 93.6 – 98.1%	98.4% (923/938)95% CI = 97.4 – 99.1%
cMRSA vs. Cefoxitin Screen	96.3% (309/321)95% CI = 93.6 – 98.1%	98.4% (923/938)95% CI = 97.4 – 99.1%
cMRSA vs. mecA PCR	100.0% (321/321)95% CI = 98.9 – 100%	97.9% (918/938)95% CI = 96.7 – 98.7%

Clinical Performance Compared to Conventional Methods after 24 h Incubation:

Cl = Confidence Interval

Performance is based on the number of true positives detected from either medium during the trial (true positives = number of samples positive by TSAB + number of samples that are false negative by TSAB and positive by chromID™ MRSA).

Conclusion:

The analytical and clinical performance data presented in this submission support a substantial equivalence decision. Based on the Substantial Equivalence Decision Tree, the chromID™ MRSA agar is substantially equivalent to the BBL™ CHROMagar™ MRSA agar.

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DEPARTMENT OF HEALTH & HUMAN SERVICES

Public Health Service

Food and Drug Administration 10903 New Hampshire Avenue Building 66 Silver Spring, MD 20993

Biomerieux, Inc. c/o Nancy Weaver Director, Regulatory Affairs 595 Anglum Rd Hazelwood, Missouri 63042

Re: K091024

Trade/Device Name: chromID™M MRSA Agar Regulation Number: 21 CFR 866.1700 Regulation Name: Antimicrobial susceptibility test Regulatory Class: II Product Code: JSO Dated: July 8, 2009 Received: July 9, 2009

Dear Ms. Weaver,

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.

JUL 1 7 2009

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to such additional controls. Existing major regulations affecting your device can be found in Title 21, Code of Federal Regulations (CFR), Parts 800 to 895. 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); and good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820). This letter will allow you to begin marketing your device as described in your Section 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

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Page 2 - Ms. Nancy Weaver

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Office or In Vitro Diagnostic Device Evaluation and Safety at 240-276-0450. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). For questions regarding postmarket surveillance, please contact CDRH's Office of Surveillance and Biometric's (OSB's) Division of Postmarket Surveillance at 240-276-3474. For questions regarding the reporting of device adverse events (Medical Device Reporting (MDR)), please contact the Division of Surveillance Systems at 240-276-3464. You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (240) 276-3150 or at its Internet address http://www.fda.gov/cdrh/industry/support/index.html.

Sincerely yours,

Foil, arthyx

Sally A. Hojvat, M.Sc., Ph.D. Director Division of Microbiology Devices Office of In Vitro Diagnostic Device Evaluation and Safety Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known):_|KD9 102 Y

Device Name: chromID™ MRSA Agar

Indications For Use:

Prescription Use × (Part 21 CFR 801 Subpart D) AND/OR

Over-The-Counter Use (21 CFR 807 Subpart C)

(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of In Vitro Diagnostic Devices (OIVD)

Ludella Poole

Division Sign-Off

Office of In Vitro Diagnostic Device Evaluation and Safety

S10(k) K091024

Page 1 of 1

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).