VITEK® 2 Gram Positive Linezolid is designed for antimicrobial susceptibility testing of Enterococcus faecalis, E. faecium, Staphylococcus aureus, S. epidermidis, S. haemolyticus and Streptococcus agalactiae. It is intended for use with the VITEK® 2 System as a laboratory aid in the determination of in vitro susceptibility to antimicrobial agents.

Device Description

The VITEK 2 AST Cards are essentially miniaturized versions of the doubling dilution technique for determining the minimum inhibitory concentration (MIC) my microdilution methodology. The bacterial isolate to be tested is diluted to a standardized concentration in 0.45% saline before being used to rehydrate the antimicrobial medium within the card. The VITEK 2 automatically fills, seals and places the card into the incubator/reader. The VITEK 2 monitors the growth of each well in the card over a defined period of time (up to 18 hours). At the completion of the incubation cycle, a report is generated that contains the MIC value along with the interpretive category result for each antibiotic contained on the card.

AI/ML Overview

The VITEK 2 Gram Positive Linezolid device's acceptance criterion for performance is defined as 98.7% overall Essential Agreement when compared to the NCCLS microbroth dilution reference method.

The study proving the device meets this criterion is an external evaluation conducted with fresh and stock clinical isolates and stock challenge strains.

Here's the detailed information requested:

1. Table of Acceptance Criteria and Reported Device Performance

Acceptance Criteria	Reported Device Performance
Overall Essential Agreement ≥ 98.7% (with NCCLS microbroth dilution reference method)	98.7% Overall Essential Agreement

2. Sample size used for the test set and the data provenance

Sample Size for Test Set: The document states that an "external evaluation was conducted with fresh and stock clinical isolates and stock challenge strains." However, the exact number of isolates or strains used in this test set is not specified within the provided text.
Data Provenance: The data is described as from "fresh and stock clinical isolates and stock challenge strains," indicating a prospective and retrospective mix for the clinical isolates, and prospective for stock challenge strains. The country of origin is not specified.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

The document does not specify the number of experts or their qualifications. The ground truth method used is the NCCLS microbroth dilution reference method, which is a standardized laboratory procedure, not typically relying on expert interpretation in the same way, for example, a medical imaging diagnosis would.

4. Adjudication method for the test set

None specified. The ground truth is established by the NCCLS microbroth dilution reference method, which is a standardized laboratory method, not typically requiring an adjudication process for its results.

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. This device is an automated antimicrobial susceptibility testing system, not an AI-assisted diagnostic tool that involves human readers interpreting results in the way an MRMC study would evaluate. Therefore, this type of study was not performed, and there is no mention of improvement in human reader performance with AI assistance.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done

Yes. The VITEK 2 system is a "Fully Automated Short-Term Incubation Cycle Antimicrobial Susceptibility Device." The performance evaluation compares the device's results directly to a reference method, which inherently describes its standalone, algorithm-only performance. The "human-in-the-loop" would be the initial preparation of the isolate and loading the card, but the interpretation and MIC determination are automated by the device.

7. The type of ground truth used

The ground truth used is the NCCLS microbroth dilution reference method. This is a laboratory-based, standardized methodology for determining minimum inhibitory concentrations (MICs) of antimicrobial agents. It is considered the gold standard for antimicrobial susceptibility testing.

8. The sample size for the training set

The document does not explicitly state a sample size for a training set. The described study is an "external evaluation" for performance confirmation. For a device incorporating a proprietary algorithm, training data would typically be used during development, but this information is not provided in the 510(k) summary.

9. How the ground truth for the training set was established

As the training set sample size is not specified, the method for establishing its ground truth is also not described in the provided text. If a training set were used, it would likely also rely on the NCCLS microbroth dilution reference method or similar standardized laboratory methods to establish ground truth for MIC values.

Summary

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K032766

OCT 3 1 2003

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510(k) SUMMARY

VITEK® 2 Gram Positive Linezolid

A. Submitter Information:

Submitter's Name:	bioMérieux, Inc.
Address:	595 Anglum RoadHazelwood, MO 63042
Contact Person:	Nancy WeaverStaff Regulatory Affairs Specialist
Phone Number:	(314) 731-8695
Fax Number:	(314) 731-8689
Date of Preparation:	September 3, 2003

B. Device Name:

Formal/Trade Name:	VITEK® 2 Gram Positive Linezolid (0.5 - 2.0 µg/ml)
Classification Name:	Fully Automated Short-Term Incubation Cycle AntimicrobialSusceptibility Device, 21 CFR 866.1645
Common Name:	VITEK 2 AST-GP Linezolid
Predicate Device:	VITEK® 2 Gram Positive Susceptibility Test for Norfloxacin(N50510/S110)

D. 510(k) Summary:

VITEK® 2 Gram Positive Linezolid is designed for antimicrobial susceptibility testing of Enterococcus faecalis, E. faecium, Staphylooocus aureus, S. epidermidis, S. haemolyticus and Streptococus agalactiae. It is intended for use with the VITEK 2 System as a laboratory aid in the determination of in vitro susceptibility to antimicrobial agents. The antimicrobial presented in VITEK 2 AST Cards is in concentrations equivalent by efficacy to standard method concentrations in mcg/ml. The VITEK 2 AST Cards are essentially miniaturized versions of the doubling dilution technique for determining the minimum inhibitory concentration (MIC) my microdilution methodology.

The bacterial isolate to be tested is diluted to a standardized concentration in 0.45% saline before being used to rehydrate the antimicrobial medium within the card. The VITEK 2 automatically fills, seals and places the card into the incubator/reader. The VITEK 2 monitors the growth of each well in the card over a defined period of time (up to 18 hours). At the completion of the incubation cycle, a report is generated that contains the MIC value along with the interpretive category result for each antibiotic contained on the card.

VITEK 2 Gram Positive Linezolid demonstrated substantially equivalent performance when compared with the NCCLS reference agar dilution method, as defined in the Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; guidance for Industry and FDA. Issued February 5, 2003.

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The Premarket Notification (510[k]) presents data in support of VITEK 2 Gram Positive Quinupristin/ dalfopristin. An external evaluation was conducted with fresh and stock clinical isolates and stock challenge strains. The external evaluations were designed to confirm the acceptability of VITEK 2 Gram Positive Linezolid by comparing its performance with the NCCLS microbroth dilution reference method. VITEK 2 Gram Positive Linezolid demonstrated acceptable performance of 98.7% overall Essential Agreement when compared to the microbroth dilution reference method. Reproducibility and Quality Control demonstrated acceptable results.

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Public Health Service

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OCT 3 1 2003

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

Ms. Nancy Weaver Staff Regulatory Affairs Specialist BioMerieux, Inc. 595 Anglum Road Hazelwood, MO 63042-2320

K032766 Re:

Trade/Device Name: VITEK 2® Gram Positive Linezolid (0.5-2.0 ug/ml) Regulation Number: 21 CFR 866.1645 Regulation Name: Fully Automated Short-Term Incubation Cycle Antimicrobial Susceptibility Devices Regulatory Class: Class II Product Code: LON Dated: September 3, 2003 Received: September 5, 2003

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.

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).

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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.

If you desire specific information about the application of labeling requirements to your device, or questions on the promotion and advertising of your device, please contact the Office of In Vitro Diagnostic Device Evaluation and Safety at (301) 594-3084. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html.

Sincerely yours,

Steven Sutman

Steven I. Gutman, M.D., M.B.A. Director Office of In Vitro Diagnostic Device Evaluation and Safety Center for Devices and Radiological Health

Enclosure

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Indications for Use Statement

510(k) Number (if known): KO327bb

Device Name: VITEK® 2 Gram Positive Linezolid (0.5 – 2.0 µg/ml)

Indications for Use:

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

Concurrence of CDRH, Office of Device Evaluation (ODE)

Luddi h. Poole

Division Sign-Off

Office of In Vitro Diagnostic Device Evaluation and Safety

510(k) K032764

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Pherymin me

Regulation Number and Section

§ 866.1645 Fully automated short-term incubation cycle antimicrobial susceptibility system.

(a)
Identification. A fully automated short-term incubation cycle antimicrobial susceptibility system is a device that incorporates concentrations of antimicrobial agents into a system for the purpose of determining in vitro susceptibility of bacterial pathogens isolated from clinical specimens. Test results obtained from short-term (less than 16 hours) incubation are used to determine the antimicrobial agent of choice to treat bacterial diseases.(b)
Classification. Class II (special controls). The special control for this device is FDA's guidance document entitled “Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA.”