Who is the manufacturer of VITEK 2 AST- Streptococcus Cefotaxime ( 8 ug/mL)?

bioMerieux, Inc. filed the 510(k) submission for VITEK 2 AST- Streptococcus Cefotaxime ( 8 ug/mL) (K210287).

What is the FDA product code for VITEK 2 AST- Streptococcus Cefotaxime ( 8 ug/mL)?

LON. It is classified under 21 CFR 866.1645 as a Class 2 device in the Microbiology panel.

What is the regulatory pathway for VITEK 2 AST- Streptococcus Cefotaxime ( 8 ug/mL)?

510(k) clearance (submission type: Traditional).

Does VITEK 2 AST- Streptococcus Cefotaxime ( 8 ug/mL) use AI or machine learning?

Yes. VITEK 2 AST- Streptococcus Cefotaxime ( 8 ug/mL) (K210287) is flagged as an AI/ML-enabled medical device in the FDA's AI/ML device list.

What are the predicate devices for VITEK 2 AST- Streptococcus Cefotaxime ( 8 ug/mL)?

Vitek 2 AST-ST Cefotaxime (K121863).

Who can help prepare an FDA 510(k) submission like VITEK 2 AST- Streptococcus Cefotaxime ( 8 ug/mL)?

Innolitics — a medical-device software consultancy — provides regulatory and engineering support for FDA 510(k) submissions. See https://innolitics.com/services/510ks/ or contact https://innolitics.com/contact.

Can an AI/ML device like VITEK 2 AST- Streptococcus Cefotaxime ( 8 ug/mL) get a guaranteed FDA 510(k) clearance?

Yes. Innolitics offers a guaranteed FDA 510(k) clearance engagement for AI/ML Software as a Medical Device — combining engineering and regulatory execution under one agreement with a guaranteed clearance outcome. Eligibility: the device must be an AI/ML Software as a Medical Device (SaMD), and its performance must meet the criteria Innolitics determines during an initial regulatory strategy engagement to be necessary for FDA clearance. See https://innolitics.com/services/end-to-end-samd/ or contact https://innolitics.com/contact.

VITEK 2 AST- Streptococcus Cefotaxime (<=0.125 - =>8 ug/mL)

K210287 · bioMerieux, Inc. · LON · Oct 28, 2021 · Microbiology

Device Facts

Record ID	K210287
Device Name	VITEK 2 AST- Streptococcus Cefotaxime (<=0.125 - =>8 ug/mL)
Applicant	bioMerieux, Inc.
Product Code	LON · Microbiology
Decision Date	Oct 28, 2021
Decision	SESE
Submission Type	Traditional
Regulation	21 CFR 866.1645
Device Class	Class 2
Attributes	AI/ML

Intended Use

VITEK® 2 AST-Streptococcus Cefotaxime is designed for antimicrobial susceptibility testing of Streptococcus spp. and is intended for use with the VITEK® 2 and VITEK® 2 Compact Systems as a laboratory aid in the determination of in vitro susceptibility to antimicrobial agents. VITEK® 2 AST- Streptococcus Cefotaxime is a quantitative test.

Device Story

VITEK 2 AST-Streptococcus Cefotaxime is an in vitro diagnostic test for determining antimicrobial susceptibility of Streptococcus species. Input: clinical isolate diluted in saline. Principle: miniaturized, automated microdilution MIC technique. Device consists of 64-well cards containing premeasured antibiotic and culture media. VITEK 2 systems automatically fill, seal, and incubate cards; VITEK 2 Compact requires manual loading. System monitors growth in wells over time. Output: quantitative MIC value and interpretive category. Used in clinical laboratories by technicians/microbiologists. Results assist clinicians in selecting appropriate antibiotic therapy for patients with streptococcal infections.

Clinical Evidence

External evaluation conducted using contemporary clinical isolates, stock isolates, and challenge strains. Performance compared to CLSI broth microdilution reference method. Results: Essential Agreement (EA) ranged from 97.3% to 100.0% across Streptococcus species. Category Agreement (CA) ranged from 89.5% to 100.0%. No Very Major Errors (VME) observed. Minor errors (mE) and Major Errors (ME) were within acceptable limits.

Technological Characteristics

Miniaturized, automated doubling-dilution AST card; 64 microwells. Sensing principle: optical light transmittance/attenuation. Energy source: electrical (VITEK 2/Compact systems). Connectivity: networked system. Software: automated growth-based detection algorithm. Reporting range: ≤0.125 - ≥8 μg/mL.

Indications for Use

Indicated for antimicrobial susceptibility testing of Streptococcus pneumoniae, Streptococcus pyogenes (Group A β-hemolytic), Streptococcus spp. (Viridans group), and Streptococcus spp. β-Hemolytic Group (other than S. pyogenes).

Regulatory Classification

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.

Special Controls

*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.”

Predicate Devices

Vitek 2 AST-ST Cefotaxime (K121863)

Related Devices

K121863 — VITEK 2 AST-ST CEFOTAXIME · bioMerieux, Inc. · Aug 16, 2012
K122359 — VITEK 2 STRPTOCOCCUS CEFTRIAXONE · bioMerieux, Inc. · Aug 28, 2012
K121100 — VITEK 2 AST STREPTOCOCUS VANCOMYCIN · bioMerieux, Inc. · Nov 19, 2012
K232201 — VITEK 2 AST-Streptococcus Penicillin (<=0.06 - =>8 µg/mL), VITEK 2 Streptococcus Penicillin (<=0.06 - >=8 µg/mL), VITEK 2 Streptococcus Penicillin · bioMerieux, Inc. · Oct 23, 2023

Submission Summary (Full Text)

{0}------------------------------------------------ Image /page/0/Picture/0 description: The image contains the logo of the U.S. Food and Drug Administration (FDA). On the left is the Department of Health & Human Services logo. To the right of that is the FDA logo, which is a blue square with the letters "FDA" in white. To the right of the blue square is the text "U.S. FOOD & DRUG ADMINISTRATION" in blue. October 28, 2021 bioMérieux, Inc Cherece L Jones Staff Regulatory Affairs Specialist 595 Anglum Rd. Hazelwood, Missouri, 63042 USA. Re: K210287 Trade/Device Name: VITEK 2 AST- Streptococcus Cefotaxime (<0.125 - >8 ug/mL) Regulation Number: 21 CFR 866.1645 Regulation Name: Fully Automated Short-Term Incubation Cycle Antimicrobial Susceptibility System Regulatory Class: Class II Product Code: LON, LTW, LTT Dated: January 29, 2021 Received: February 2, 2021 Dear Cherece Jones: 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. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. 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 Part {1}------------------------------------------------ 801 and Part 809); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or post marketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4. Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050. 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 https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems. For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100). Sincerely, Ribhi Shawar, Ph.D. (ABMM) Chief General Bacteriology and Antimicrobial Susceptibility Branch Division of Microbiology Devices OHT7: Office of In Vitro Diagnostics and Radiological Health Office of Product Evaluation and Quality Center for Devices and Radiological Health Enclosure {2}------------------------------------------------ ## Indications for Use 510(k) Number (if known) K210287 Device Name VITEK® 2 AST- Streptococcus Cefotaxime (≤0.125 - ≥8 µg/mL) #### Indications for Use (Describe) VITEK® 2 AST-Streptococcus Cefotaxime is designed for antimicrobial susceptibility testing of Streptococcus spp. and is intended for use with the VITEK® 2 and VITEK® 2 Compact Systems as a laboratory aid in the determination of in vitro susceptibility to antimicrobial agents. VITEK® 2 AST- Streptococcus Cefotaxime is a quantitative test. Cefotaxime has been shown to be active against most strains of the microorganisms listed below, according to the FDA label for this antimicrobial. #### Active in vitro and in clinical infections: Streptococcus pneumoniae Streptococcus pyogenes (Group A beta-hemolytic streptococci)* Streptococcus spp. (Viridans group streptococci) *The VITEK® 2 Streptococus Susceptibility Card also reports the susceptibility of the following additional organisms as listed on the FDA Susceptibility Test Interia website (STIC): Streptococcus spp. B-Hemolytic Group (other than S. pyogenes). The VITEK® 2 Streptococcus Susceptibility Card is intended for use with the VITEK® 2 Systems in clinical laboratories as an in vitro test to determine the susceptibility of S. pneumoniae, beta-hemolytic Streptococcus, and Viridans Streptococcus to antimicrobial agents when used as instructed. Type of Use (Select one or both, as applicable) | ☑ Prescription Use (Part 21 CFR 801 Subpart D) | ☐ Over-The-Counter Use (21 CFR 801 Subpart C) | |-------------------------------------------------------------|------------------------------------------------------------| |-------------------------------------------------------------|------------------------------------------------------------| #### CONTINUE ON A SEPARATE PAGE IF NEEDED. This section applies only to requirements of the Paperwork Reduction Act of 1995. #### *DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW! * The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to: > Department of Health and Human Services Food and Drug Administration Office of Chief Information Officer Paperwork Reduction Act (PRA) Staff PRAStaff@fda.hhs.gov "An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number." {3}------------------------------------------------ Image /page/3/Picture/0 description: The image shows the logo for bioMérieux. The logo is a circle that is split into two halves. The top half is blue and contains the word "BIOMÉRIEUX" in white, sans-serif font. The bottom half of the circle is yellow and green. ### 510(k) SUMMARY ## VITEK® 2 AST-Streptococcus Cefotaxime (≤0.125 - ≥8 µg/mL) ### A. 510(k) Submission Information: | Submitter's Name: | bioMérieux, Inc. | |----------------------|----------------------------------------------------------------------------------------------------------------------------| | Address: | 595 Anglum Road Hazelwood, MO 63042 | | Contact Person: | Cherece L. Jones Staff Regulatory Affairs Specialist | | Phone Number: | 314 -731-8684 | | Fax Number: | 314-731-8689 | | Date of Preparation: | January 29, 2021 | | B. Device Name: | | | Formal/Trade Name: | VITEK® 2 AST- Streptococcus Cefotaxime (≤0.125 - ≥8 µg/mL) | | Classification Name: | 21 CFR 866.1645 Fully Automated Short-Term Incubation Cycle Antimicrobial Susceptibility System Product Code: LON | | Common Name: | VITEK® 2 AST-ST Cefotaxime (≤0.125 - ≥8 µg/mL) | | C. Predicate Device: | VITEK® 2 AST-Streptococcus Cefotaxime (≤0.125 - ≥8 µg/mL) (K121863) | ### D. Device Description: The principle of the VITEK® 2 AST cards is based on the microdilution minimum inhibitory concentration (MIC) technique reported by MacLowry and Marsh(1) and Gerlach(0). The VITEK @ 2 AST card is essentially a miniaturized, abbreviated and automated version of the doubling dilution technique(3). {4}------------------------------------------------ Image /page/4/Picture/0 description: The image shows the logo for bioMérieux. The logo consists of a blue circle on top and a yellow-green circle on the bottom, separated by a white line. The word "BIOMÉRIEUX" is written in white letters in the center of the blue circle. Each VITEK® 2 AST card contains 64 wells. A control well which only contains microbiological culture media is resident on all cards. The remaining wells contain premeasured portions of a specific antibiotic combined with culture media. The isolate to be tested is diluted to a standardized concentration with 0.45 - 0.5% saline before being used to rehydrate the antimicrobial medium within the card. The VITEK® 2 System automatically fills, seals and places the card into the incubator/reader. The VITEK® 2 Compact has a manual filling, sealing and loading operation. The VITEK® 2 Systems monitor the growth of each well in the card over a defined period of time. 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. ### E. Substantial Equivalence Information: The similarities and differences of the VITEK® 2 AST- Streptococcus Cefotaxime (≤0.125 - ≥8 ug/mL) when compared to the predicate device, VITEK® 2 AST-Streptococcus Cefotaxime (<0.125 - ≥8 µg/mL) (K121863), are described in Table 1 below. | Item | Device: VITEK® 2 AST- Streptococcus Cefotaxime (≤0.125 - ≥8 µg/mL) (K210287) | Predicate: VITEK® 2 AST-Streptococcus Cefotaxime (≤0.125 - ≥8 µg/mL) (K121863) | |--------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------| | General Device Characteristic Similarities | | | | Intended Use/Indications for Use | VITEK® 2 AST-Streptococcus Cefotaxime is designed for antimicrobial susceptibility testing of Streptococcus spp. and is intended for use with the VITEK® 2 and VITEK® 2 Compact Systems as a laboratory aid in the determination of in vitro susceptibility to antimicrobial agents. VITEK® 2 AST- Streptococcus Cefotaxime is a quantitative test. | Same | | Test Methodology | Automated quantitative antimicrobial susceptibility test for use with the VITEK® 2 and VITEK® 2 Compact Systems to determine the in vitro susceptibility of microorganisms | Same | | Antimicrobial Agent | Cefotaxime | Same | | Inoculum | Saline suspension of organism | Same | | Test Card | Streptococcus (AST-ST) Susceptibility Card | Same | | Analysis Algorithms | Discriminate Analysis | Same | | Instrument | VITEK® 2 and VITEK® 2 Compact Systems | Same | ### Table 1: Substantial Equivalence {5}------------------------------------------------ Image /page/5/Picture/0 description: The image shows the logo for bioMérieux, a French multinational biotechnology company. The logo consists of a circle divided into two sections. The top section is a dark blue color and contains the company name "BIOMÉRIEUX" in white, sans-serif font. The bottom section is a gradient that transitions from yellow to green. | | Device: | Predicate: | |-------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | Item | VITEK® 2 AST- Streptococcus Cefotaxime (≤0.125 - ≥8 µg/mL) (K210287) | VITEK® 2 AST-Streptococcus Cefotaxime (≤0.125 - ≥8 µg/mL) (K121863) | | Concentrations | 0.25, 0.5, 1, 2 | Same | | General Device Characteristic Differences | | | | Indicated Organisms | Cefotaxime has been shown to be active against most strains of the microorganisms listed below, according to the FDA label for this antimicrobial. Active in vitro and in clinical infections: Streptococcus pneumoniae Streptococcus pyogenes (Group A beta-hemolytic streptococci)* Streptococcus spp. (Viridans group streptococci) *The VITEK® 2 Streptococcus Susceptibility Card also reports the susceptibility of the following additional organisms as listed on the FDA Susceptibility Test Interpretative Criteria website (STIC): Streptococcus spp. ß- Hemolytic Group (other than S. pyogenes ). The VITEK® 2 Streptococcus Susceptibility Card is intended for use with the VITEK® 2 Systems in clinical laboratories as an in vitro test to determine the susceptibility of S. pneumoniae , beta-hemolytic Streptococcus , and Viridans Streptococcus to antimicrobial agents when used as instructed | Cefotaxime has been shown to be active against most strains of the microorganism listed below, according to the FDA label for this antimicrobial. Active in vitro and in clinical infections: Streptococcus pneumoniae , Streptococcus pyogenes (Group A beta-hemolytic streptococci), Streptococcus spp. The VITEK® 2 Antimicrobial Susceptibility Test (AST) is intended to be used with the VITEK® 2 and VITEK 2 Compact Systems for the automated quantitative or qualitative susceptibility testing of isolated colonies for the most clinically significant aerobic gram-negative bacilli, Staphylococcus spp., Enterococcus spp., Streptococcus agalactiae , and S. pneumoniae . | ## F. Performance Overview and Conclusion: VITEK® 2 AST-ST Cefotaxime (≤0.125 - ≥8 µg/mL) demonstrated substantially equivalent performance when compared with the CLSI broth microdilution reference method, as defined in the FDA Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA (Issued August 28, 2009). {6}------------------------------------------------ Image /page/6/Picture/0 description: The image shows the logo for bioMérieux. The logo consists of a blue circle on top of a green and yellow circle. The word "BIOMÉRIEUX" is written in white letters in the center of the blue circle. The Premarket Notification (510|k]) presents data in support of VITEK® 2 AST-ST Cefotaxime. An external evaluation was conducted with contemporary and stock clinical isolates, as well as a set of challenge strains. The external evaluations were designed to confirm the acceptability of AST-ST Cefotaxime by comparing its performance with the CLSI broth microdilution reference method incubated at 20-24 hrs (i.e. Streptococcus). The data is representative of performance on both the VITEK® 2 and VITEK® 2 Compact instrument platforms. The VITEK® 2 AST-ST Cefotaxime (≤0.125 - ≥8 µg/mL) demonstrated acceptable performance as presented in Table 2 below: | Antimicrobial | Antimicrobial Code | Antibiotic Version | Bp1 | Comment2 | Essential Agreement Category | | | | Category Agreement | | | | % Repr du cibilit | |---------------|-----------------------|-----------------------|---------------|------------------------------------------------------------------------------------------|------------------------------|-----|-----|-----|--------------------|---------------|----------------|------------------|-------------------| | | | | | | % Error | | | | % Error | | | | | | | | | | | %EA | VME | ME | mE | %CA | VME | ME | mE | | | Cefotaxime* | CTX | (ctx01n) | FDA (CLSI) | #, E Streptococcus pneumoniae (meningitis) | (346/351) 98.6 | N/A | N/A | N/A | (314/351) 89.5 | (0/54) 0.0 | (2/243) 0.8 | (35/351) 10.0 | | | | | | | #, E Streptococcus pneumoniae (non - meningitis) | (346/351) 98.6 | N/A | N/A | N/A | (315/351) 89.7 | (0/23) 0.0 | (1/297) 0.3 | (35/351) 10.0 | | | | | | | #, E Streptococcus pyogenes (Group A β- Hemolytic GroupNS | (310/310) 100.0 | N/A | N/A | N/A | (310/310) 100.0 | (0/0) 0.0 | (0/310) 0.0 | N/A | 100.0 | | | | | | #, E Streptococcus spp. β- Hemolytic Group (other than S. pyogenes) NS | (554/554) 100.0 | N/A | N/A | N/A | (554/554) 100.0 | (0/0) 0.0 | (0/554) 0.0 | N/A | | | | | | | #, E Streptococcus spp. Viridans Group | (397/408) 97.3 | N/A | N/A | N/A | (396/408) 97.1 | (0/12) 0.0 | (0/381) 0.0 | (12/408) 2.9 | | # Toble 21 VITEV® 2 AST ST Cafatoximo Porformonea The VITEK 2 Cefotaxime MC values for Streptococus spp Viridans Group ended to be at least one than the reference method and may contibute to the occurrence of very major errors. NS - The current absence of resistant isolates defining any results other than susceptible. Isolates pieding MC results suggestive of Nonsuceptible category should be submitted to a reference laboratory for further testing. {7}------------------------------------------------ Image /page/7/Picture/0 description: The image shows the logo for bioMérieux. The logo is a circle with the top half being blue and the bottom half being yellow-green. The word "BIOMÉRIEUX" is written in white letters in the center of the blue portion of the circle. *For specific information regarding succession and associaed test methods and quality contriss standards recognized by FDA for his drug, pleas sec https://www.fda.gov/STIC Kev: # = US Food and Drug Administration 510(k) cleared E = External performance data Quality Control demonstrated acceptable results. ### G. Limitations: The ability of the AST card to detect resistance with the following combination(s) is unknown because resistant strains were either not available or an insufficient number were encountered at the time of comparative testing: - Cefotaxime (ctx01n): Streptococcus pyogenes (Group A ß-hemolytic streptococci) and ● Streptococcus spp ß-Hemolytic Group (other than S. pyogenes) #### H. References: - MacLowry, J.D. and Marsh, H.H., Semi-automatic Microtechnique for Serial Dilution Antibiotic 1. Sensitivity Testing in the Clinical laboratory, Journal of Laboratory Clinical Medicine, 72:685-687, 1968. - Gerlach, E.H., Microdilution 1: A Comparative Study, p. 63-76. Current Techniques for 2. Antibiotic Susceptibility Testing. A. Balows (ed.), Charles C. Thomas, Springfield, IL, 1974. - Barry, A.L., The Antimicrobic Susceptibility Test, Principles and Practices, Lea and Febiger, 3. Philadelphia, PA, 1976.