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Antibacterial Susceptibility Test Interpretive Criteria

This web page provides information about the in vitro susceptibility of bacteria to certain drugs.

The safety and efficacy of these drugs in treating clinical infections due to such bacteria may or may not have been established in adequate and well-controlled clinical trials and the clinical significance of such susceptibility information in those instances is unknown.

The approved product labeling for specific drugs provides the uses for which the product is approved.

Labeling for these products can be found at Drugs@FDA or FDA Online Label Repository.

Recognized Standards

Performance Methods and Quality Control

FDA recognizes consensus standards for performance standards, methods standards, and quality control parameter standards including ranges for antimicrobial susceptibility testing.

Susceptibility Test Interpretive Criteria

The table below lists antibacterial drugs and indicates which, if any, susceptibility test interpretive criteria, also known as “breakpoints” (abbreviated as STIC), are recognized or identified by FDA for that drug.

With certain exceptions and additions, identified in the table, FDA recognizes the standard published in:

  • Clinical and Laboratory Standards Institute (CLSI). Performance Standards for Antimicrobial Susceptibility Testing. 29th ed. CLSI supplement M100. Wayne, PA: Clinical and Laboratory Standards Institute; 2019. (CLSI M100disclaimer icon)

If the table indicates that STIC for a drug are included in CLSI M100 and there are no additions or exceptions, CLSI M100 contains all of the STIC recognized by FDA for that drug.

For specific drug/bacteria combinations, FDA recognizes in part the standards published in:

  • Clinical and Laboratory Standards Institute (CLSI). Methods for Antimicrobial Dilution and Disk Susceptibility Testing of Infrequently Isolated or Fastidious Bacteriai. 3rd ed. CLSI guideline M45. Wayne, PA: Clinical and Laboratory Standards Institute; 2015.
  • Clinical and Laboratory Standards Institute (CLSI). Susceptibility Testing of Mycobacteria, Nocardiae, and Other Aerobic Actinomycetes; Approved Standard. 2nd ed. CLSI guideline M24-A2. Wayne, PA: Clinical and Laboratory Standards Institute; 2011.
  • Clinical and Laboratory Standards Institute (CLSI). >Methods for Antimicrobial Susceptibility Testing for Human Mycoplasmas; Approved Guideline. CLSI guideline M43-A. Wayne, PA: Clinical and Laboratory Standards Institute; 2011.

If one of these three standards is recognized in part, that information is provided in the hyperlinked information for the specific drug listed in the table below.

FDA recognition of STIC standard(s) for a drug does not include recognition of epidemiological cutoff values (ECVs) for that drug.

FDA recognition of STIC standard(s) for a drug and bacterial family or genus/species does include recognition of surrogate testing methods included in recognized standards for that drug and bacterial family or genus/species.

Susceptibility Test Interpretive Criteria Recognized or Otherwise Identified by FDA

The hyperlinks included for certain antibacterial drugs in the table below lead to information concerning:

  • Recognitions, Exceptions, or Additions to the recognized standard of CLSI M100
  • Additional STIC recognized in part from standards CLSI M45, M24-A2, and M43-A
  • Additional FDA-identified STIC for certain drug-bacteria combinations not included in a recognized standard

Downloadable File (XLS-16KB)


Route of

STIC for Drug
Included in

Exceptions or
Additions to

Last Updated

Amikacin Injection Yes Yes 12/13/17
Amoxicillin Oral Yes No 12/13/17
and clavulanate
Oral Yes Yes 12/13/17
Ampicillin Injection, Oral Yes No 12/13/17
Ampicillin and
Injection Yes Yes 12/13/17
Azithromycin Injection, Oral Yes Yes 6/10/19
Aztreonam Injection Yes Yes 12/13/17
Bacitracin* Injection No No 12/13/17
Bedaquiline* Oral No No 12/13/17
Bismuth subcitrate potassium, Metronidazole, and Tetracycline hydrochloride* Oral No No 02/09/18
Capreomycin* Injection No No 12/13/17
Cefaclor Oral Yes Yes 12/13/17
Cefadroxil Oral No Yes 12/13/17
Cefazolin Injection Yes Yes 12/13/17
Cefdinir Oral Yes Yes 12/13/17
Cefditoren pivoxil Oral Yes Yes 12/13/17
Cefepime Injection Yes Yes 12/13/17
Cefiderocol Injection Yes Yes 9/25/20
Cefixime Oral Yes No 12/13/17
Cefoperazone Injection Yes Yes 12/13/17
Cefotaxime Injection Yes Yes 12/13/17
Cefotetan Injection Yes Yes 12/13/17
Cefoxitin Injection Yes Yes 12/13/17
Oral Yes No 12/13/17
Cefprozil Oral Yes Yes 12/13/17
Ceftaroline fosamil Injection Yes Yes 4/16/20
Ceftazidime Injection Yes Yes 12/13/17
Ceftazidime and
Injection Yes No 06/26/18
Ceftibuten Oral Yes Yes 12/13/17
Ceftolozane and
Injection Yes Yes 06/10/19
Ceftriaxone Injection Yes Yes 12/13/17
Cefuroxime axetil Oral Yes Yes 12/13/17
Cefuroxime Injection Yes Yes 6/10/19
Cephalexin Oral Yes No 12/13/17
Chloramphenicol Injection Yes Yes 12/13/17
Ciprofloxacin Oral, Injection Yes Yes 2/28/20
Clarithromycin Oral Yes Yes 02/09/18
Clindamycin Injection, Oral Yes No 12/13/17
Clofazimine* Oral No No 12/13/17
Colistimethate Injection Yes Yes 6/10/19
Dalbavancin Injection Yes No 06/26/18
Dapsone* Oral No No 12/13/17
Daptomycin Injection Yes Yes 8/25/20
Delafloxacin Injection, Oral No Yes 10/06/20
Demeclocycline Oral No Yes 12/13/17
Dicloxacillin Oral Yes No 12/13/17
Doripenem Injection Yes Yes 12/13/17
Doxycycline Oral, Injection Yes Yes 12/13/17
Eravacycline Injection No Yes 8/28/2018
Ertapenem Injection Yes Yes 12/13/17
Erythromycin Oral, Injection Yes No 12/13/17
ethylsuccinate and
Oral No No 12/13/17
Ethambutol* Oral No No 12/13/17
Ethionamide* Oral No No 12/13/17
Fidaxomicin* Oral No No 12/13/17
Oral Yes No 12/13/17
Gemifloxacin Oral Yes No 12/13/17
Gentamicin Injection Yes Yes 12/13/17
Imipenem and
Injection Yes Yes 12/13/17
Injection No Yes 6/04/20
Isoniazid* Oral No No 12/13/17
Isoniazid, Pyrazinamide, and Rifampin* Oral No No 02/09/18
Kanamycin Injection Yes Yes 12/13/17
Lansoprazole, Amoxicillin, and Clarithromycin* Oral No No 02/09/18
Lefamulin Oral, Injection No Yes 8/29/19
Levofloxacin Oral, Injection Yes Yes 2/28/20
Lincomycin* Injection No No 12/13/17
Linezolid Injection, Oral Yes No 12/13/17
Loracarbef Oral Yes Yes 12/13/17
Meropenem Injection Yes Yes 01/02/20
Meropenem and
Injection Yes No 6/10/19
Oral No No 12/13/17
Metronidazole Injection, Oral Yes No 12/13/17
Minocycline Oral, Injection Yes Yes 12/13/17
Moxifloxacin Oral, Injection Yes Yes 12/13/17
Nafcillin* Injection No No 12/13/17
Neomycin sulfate* Oral No No 12/13/17
Nitrofurantoin Oral Yes No 12/13/17
Ofloxacin Oral Yes Yes 2/28/20
Omadacycline Injection, Oral No Yes 8/25/20
Omeprazole magnesium, Amoxicillin, and Rifabutin* Oral No No 11/18/19
Injection Yes No 12/13/17
Oxacillin Injection Yes No 12/13/17
Penicillin Injection Yes No 12/13/17
Penicillin V Oral Yes No 12/13/17
Piperacillin and
Injection Yes Yes 06/26/18
Plazomicin Injection No Yes 06/26/18
Polymyxin B
Injection Yes Yes 12/13/17
Pretomanid* Oral No No 8/29/19
Pyrazinamide* Oral No No 12/13/17
Quinupristin and
Injection Yes Yes 12/13/17
Rifabutin* Oral No No 4/26/18
Rifampin Oral, Injection Yes Yes 12/13/17
Rifapentine* Oral No No 02/09/18
Rifaximin* Oral No No 02/09/18
Spectinomycin Injection Yes No 12/13/17
Streptomycin Injection Yes Yes 12/13/17
Tedizolid Oral, Injection Yes Yes 06/26/18
Telavancin Injection Yes No 12/13/17
Telithromycin Oral Yes Yes 12/13/17
Tetracycline Oral Yes Yes 12/13/17
Ticarcillin and
Injection Yes Yes 12/13/17
Tigecycline Injection No Yes 12/13/17
Tobramycin Injection Yes Yes 12/13/17
Oral Yes No 12/13/17
Trimethoprim and
Oral, Injection Yes Yes 12/13/17
Vancomycin Injection Yes Yes 12/13/17
Vancomycin* Oral No No 12/13/17

*No STIC are recognized by FDA for this drug at this time.

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