BD BBL™ CHROMagar™ 0157 is a selective medium for the isolation, differentiation and presumptive identification of Escherichia coli 0157:H7 from clinical human stool specimens.

Device Description

BBL™ CHROMagar™ O157 formulation incorporates chromogenic substrates, which allow colonies of E. coli O157:H7 to produce a mauve color for presumptive identification from the primary isolation plate and differentiation from other organisms. Specially selected Difco™ peptones are incorporated to supply nutrients. The addition of potassium tellurite, cefixime and cefsulodin reduces the number of bacteria other than E. coli O157:H7 that grow on this medium. The chromogen mix consists of artificial substrates (chromogens), which release an insoluble colored compound when hydrolyzed by a specific enzyme. E. coli O157:H7 utilizes one of the chromoqenic substrates producing mauve colonies. The growth of mauve colonies is considered presumptive for E. coli 0157:H7 on BBL™ CHROMagar™ 0157. Non-E. coli O157:H7 bacteria may utilize other chromogenic substrates resulting in blue-green colored colonies or, if none of the chromogenic substrates are utilized, colonies may appear as their natural color. These visually distinct colored colonies facilitate the detection and differentiation of E. coli 0157:H7 from other organisms.

AI/ML Overview

Here's an analysis of the provided text regarding the acceptance criteria and study for the BBL™ CHROMagar™ O157 device:

BBL™ CHROMagar™ O157 Device Study Summary

1. Acceptance Criteria and Reported Device Performance

The direct acceptance criteria are not explicitly stated as numerical thresholds in the provided text. However, the study aims to demonstrate that BBL™ CHROMagar™ O157 performs "as well as" the predicate device (SMAC) and another commercially available medium (SMAC-CT) in presumptively identifying E. coli O157:H7. The results from the external clinical study provide the performance metrics against the predicate device.

Table of Performance:

Metric	Reported Device Performance (BBL™ CHROMagar™ O157 vs. SMAC)
Positive Percent Agreement	86.4%
Negative Percent Agreement	99.8%

2. Sample Size and Data Provenance

Test Set Sample Size: 3,136 stool specimens were initially cultured, with 2,855 providing acceptable results for the study.
Data Provenance: The external clinical study was conducted at "an external centralized regional clinical laboratory that routinely tests for E. coli O157:H7 in stool specimens." The country of origin is not explicitly stated, but the context (FDA 510(k) submission, Department of Health & Human Services USA) strongly suggests it was conducted in the United States.
Retrospective or Prospective: The study describes specimens being "inoculated onto Sorital-MacConkey (SMAC) and BBL CHROMagar O157 media," implying a prospective collection and testing of new specimens at the time of the study, rather than analyzing existing archived data.

3. Number of Experts and Qualifications for Ground Truth

Number of Experts: "Each Plate was read by an independent technologist." The exact number of technologists involved is not specified, but it implies at least two (one for SMAC, one for CHROMagar, though it might have been the same technologist reading both, followed by confirmatory testing). It doesn't appear that multiple experts independently read the same plates to establish a consensus ground truth at the reading stage.
Qualifications of Experts: The experts are referred to as "independent technologist(s)." Specific qualifications (e.g., years of experience, certifications) are not detailed in the provided text.

4. Adjudication Method for the Test Set

The primary method for establishing the definitive ground truth (beyond the initial technologist reading) was: "confirmatory testing (indole and serotyping) was conducted on all suspected colony samples." This indicates that any suspected positive result from either the SMAC or BBL CHROMagar O157 plates underwent further definitive laboratory testing. This is a form of confirmatory testing adjudication, where definitive lab tests serve as the ultimate arbiter, rather than a consensus among human readers of the primary plates.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No, a multi-reader multi-case (MRMC) comparative effectiveness study was not conducted in the typical sense of measuring human reader improvement with or without AI assistance. This device is a culture medium, not an AI-powered diagnostic tool for interpretation. The comparison is between the BBL™ CHROMagar™ O157 medium and predicate media, both of which are interpreted manually by a technologist.

6. Standalone Performance Study

Yes, a standalone study was performed in the sense that the performance of the BBL™ CHROMagar™ O157 medium was evaluated independently. The "External Studies" section details its performance (Positive Percent Agreement and Negative Percent Agreement) in comparison to the SMAC medium based on the final confirmatory testing. The "Internal Studies" also included a Limit of Detection study and a cross-reactivity study, which assess the medium's inherent performance.

7. Type of Ground Truth Used

The ground truth used for the external clinical study was primarily confirmatory laboratory testing, specifically "indole and serotyping" performed on "all suspected colony samples." This represents a high-level, definitive laboratory identification of E. coli O157:H7.

8. Sample Size for the Training Set

The document does not mention a training set size. This is because the BBL™ CHROMagar™ O157 is a traditional in-vitro diagnostic culture medium, not a machine learning or artificial intelligence algorithm that requires a training set.

9. How Ground Truth for the Training Set Was Established

As there is no training set for this type of device, this question is not applicable. The device's formulation and chromogenic properties are based on biological principles, not on learned patterns from a dataset.

Summary

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K070691

510(k) SUMMARY

SUBMITTED BY:

BECTON, DICKINSON AND COMPANY 7 LOVETON CIRCLE SPARKS, MD 21152 Phone: 410-316-4099 410-316-4499 Fax:

Dennis Mertz, Sr. Manager, Regulatory Affairs CONTACT NAME: NOV # 0 2007 DATE PREPARED: November 8, 2007 DEVICE TRADE NAME: BBL™ CHROMagar™ 0157 Differential Culture Medium DEVICE COMMON NAME: DEVICE CLASSIFICATION:

PREDICATE DEVICES: BBL ™ MacConkey II Agar with Sorbitol (K871855)

INTENDED USE:

BBL ™ CHROMagar™ 0157 is a selective medium for the isolation, differentiation and presumptive identification of Escherichia coli 0157:H7 from clinical human stool specimens.

21 CFR § 866.2360 Class I

DEVICE DESCRIPTION:

DEVICE COMPARISON:

The BBL™ CHROMagar™ 0157 medium differs from the BBL™ MacConkey II Agar with Sorbitol medium in the following ways:

. BBL CHROMagar 0157 utilizes a chromogenic mix to differentiate E. coli 0157:H7 from other E. coli and fecal organisms, whereas BBL MacConkey II Agar with Sorbitol utilizes sorbitol and neutral red indicator to differentiate E. coli 0157:H7 from other E. coli strains.
. BBL CHROMagar O157 utilizes tellurite, cefixime and cefsulodin as selective agents to reduce and/or inhibit bacterial growth other than E. coli 0157:H7, whereas BBL MacConkey II Agar with Sorbitol utilizes bile salts and crystal violet as selective agents to reduce and/or inhibit bacterial growth.
. BBL CHROMagar 0157 presumptively identifies E. coli 0157:H7 by its ability to hydrolyze a specific substrate that produces a mauve color, whereas BBL MacConkey II Agar with Sorbitol presumptively identifies E. coli 0157:H7 by its inability to ferment sorbitol thereby producing a colorless colony.

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CONFIDENTIAL - BD Diagnostic Systems

Although there are some differences between the BBL™ CHROMagar™ 0157 device and its predicate device (BBL™ MacConkey II Agar with Sorbitol), these differences do not present new issues of safety and effectiveness. The impact of these differences on the safety and effectiveness of the BBL ™ CHROMagar™ O157 device can be assessed by using accepted scientific methods. Comparative performance data are presented in this submission.

The following table shows the comparison of device characteristics of BBL CHROMagar 0157 to BBL MacConkey II Agar with Sorbitol.

Device Characteristic	BBL CHROMagar O157	BBL MacConkey II Agar with Sorbitol(SMAC) (K871855)
Intended Use	BBL CHROMagar 0157 is a selectivemedium for the isolation, differential andpresumptive identification of Escherichiacoli O157:H7 from clinical stool sources.	BBL MacConkey II Agar with Sorbitol isused as a selective and differentialmedium for the detection of Escherichiacoli serotype 0157:H7 associated withhemorrhagic colitis.
Specimen type	Clinical specimens	Clinical specimens
Inoculation	Direct from specimen or specimencollection device.	Direct from specimen or specimencollection device
Storage Conditions	Refrigeration at 2 - 8°C away from light	Refrigeration at 2 - 8°C
Incubation Temperature	Incubation at 35 ± 2°C, protected fromlight	Incubation at 35 ± 2°C, protected fromlight
Incubation Length	18-24 h.	18-24 h.
Selective Inhibitory agents	Tellurite, Cefixime, and Cefsulodin	Bile salt and Crystal Violet
Testing Method	Manual	Manual
Growth Detection	Identification at 18-24 h.	Identification at 18-24 h.
Organism Differentiation	Chromogen mix substrates facilitatevisual differentiation of E. coli O157:H7from other E. coli and other fecalorganisms.	Sorbitol and Neutral red indicatorfacilitate visual differentiation of E. coli0157:H7 from other E. coli and otherfecal organisms.
Shelf Life	12 weeks	12 weeks

Table 1:	Device Characteristics Comparison of BBL CHROMagar O157 to BBL MacConkey II
	Agar with Sorbitol (SMAC)

SUMMARY OF PERFORMANCE DATA:

ANALYTICAL STUDIES:

Internal Studies:

An internal evaluation of BBL™ CHROMagar™ 0157 was performed in the Research & Development Laboratory of BD Diagnostic Systems. Testing included 1) a study comparing the performance of BBL ™ CHROMagar™ O157 to two commercially available, selective and differential media used for the presumptive identification for E. coli O157:H7 [BBL™ MacConkey II Agar with Sorbitol (SMAC) and BBL™ Sorbitol MacConkey II Agar with Cefixime and Tellurite (SMAC-CT)], 2) a Limit of Detection study, and 3) a verification study of product performance using a latex agglutination test. These tests demonstrate that BBL CHROMagar 0157 performs as well as the predicate device, SMAC and another commercially available medium (SMAC-CT) in presumptively identifying E. coli 0157:H7.

Additional analytical studies were conducted with BBL CHROMagar 0157 to demonstrate the performance of the medium under a number of variable conditions. This testing included 1) a cross reactivity study using fifty-nine (59) non-E. coli 0157:H7 organisms including various species from the following Geneses: Salmonella, Shigella, Yersinia, Vibrio, Aeromonas, Campylobacter and Plesiomonas, and 2) an interference study using fourteen (14) substances that may be present in stool or rectal specimens. These substances included lubricants, water, soap, laxatives, suppositories and various hemorrhoidal treatments.

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The results for the cross reactivity study indicated that only one of the 59 organisms, Salmonella serotype Heidelberg, exhibited mauve colonies when plated on BBL. CHROMagar 0157. The results of the interference study showed that none of the substances tested interfered with the performance of the BBL CHROMagar 0157 medium.

External Studies:

A clinical study was conducted at an external centralized regional clinical laboratory that rountinely tests for E. coli 0157:H7 in stool specimens were inoculated onto Sorital-MacConkey (SMAC) and BBL CHROMagar 0157 media and incubated aerobically for 18-24 hours at 35°C. Each Plate was read by an independent technologist and confirmatory testing (indole and serotyping) was conducted on all suspected colony samples. A total of 3,136 stool specimens were cultured, of which 2,855 specimens provided acceptable results for this study while 281 specimens were determined to the noncompliant to the required testing matrix. The following table shows the breakdown of the results from this study:

	SMAC Result
CHROMagar Result	Positive	Negative
Positive	19	5
Negative	3	2828
Totals	22	2833

Positive Percent Agreement: 86.4% Negative Percent Agreement: 99.8%

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DEPARTMENT OF HEALTH & HUMAN SERVICES

Image /page/3/Picture/1 description: The image shows the seal of the Department of Health & Human Services USA. The seal is circular, with the words "DEPARTMENT OF HEALTH & HUMAN SERVICES USA" arranged around the perimeter. In the center of the seal is an abstract symbol that resembles an eagle or bird-like figure. The symbol is composed of three curved lines that converge at the bottom.

Public Health Service

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

NOV 2 0 2007

Mr. Dennis Mertz Senior Manager, Regulatory Affairs Becton, Dickinson and Company 7 Loveton Circle Sparks, MD 21152

K070691 Re:

Trade/Device Name: BBLIM CHROMagar TM 0157 Regulation Number: 21 CFR 866.2360 Regulation Name: Differential Culture Medium Regulatory Class: Class I Product Code: JSI Dated: October 10 2007 Received: October 11, 2007

Dear Mr. Mertz:

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 advice for your device on our labeling regulation (21 CFR Part 801), please contact the Office of 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 vours,

Sally attayna

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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Indication for Use

510(k) Number: K070691

BD BBL™ CHROMagar™ 0157 Device Name:

Indication For Use:

BD BBL™ CHROMagar™ 0157 is a selective medium for the isolation, differentiation and presumptive identification of Escherichia coli 0157:H7 from clinical human stool specimens.

X Prescription Use (21 CFR Part 801 Subpart D)

And/Or

Over the Counter Use (21 CFR Part 801 Subpart C)

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

Concurrence of CDRH, Office of In Vitro Diagnostic Device Evaluation and Safety (OIVD)

Freddie M. Poole

Msion Sign-Off Office of In Vitro Diagnostic Device Evaluation and Safety

510(k) K070691

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Regulation Number and Section

§ 866.2360 Selective culture medium.

(a)
Identification. A selective culture medium is a device that consists primarily of liquid or solid biological materials intended for medical purposes to cultivate and identify certain pathogenic microorganisms. The device contains one or more components that suppress the growth of certain microorganisms while either promoting or not affecting the growth of other microorganisms. The device aids in the diagnosis of disease caused by pathogenic microorganisms and also provides epidemiological information on these diseases.(b)
Classification. Class I (general controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 866.9.