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. 34th ed. CLSI supplement M100. Clinical and Laboratory Standards Institute; 2024.
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 Bacteria. 3rd ed. CLSI document M45; 2015.
Clinical and Laboratory Standards Institute (CLSI). Performance Standards for Susceptibility Testing of Mycobacteria, Norcardia spp. and other Aerobic Actinomycetes. 1st ed. CLSI document M62; 2018.
Clinical and Laboratory Standards Institute (CLSI). Methods for Antimicrobial Susceptibility Testing for Human Mycoplasmas; Approved Guideline. CLSI document M43-A; 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-23KB)
Drug |
Route of |
STIC for Drug |
Exceptions or |
---|---|---|---|
Amikacin | Injection | Yes | Yes |
Amoxicillin | Oral | Yes | No |
Amoxicillin and clavulanate |
Oral | Yes | Yes |
Ampicillin | Injection, Oral | Yes | No |
Ampicillin and sulbactam |
Injection | Yes | Yes |
Azithromycin | Injection, Oral | Yes | Yes |
Aztreonam | Injection | Yes | Yes |
Bacitracin* | Injection | No | No |
Bedaquiline* | Oral | No | No |
Bismuth subcitrate potassium, Metronidazole, and Tetracycline hydrochloride* | Oral | No | No |
Capreomycin* | Injection | No | No |
Cefaclor | Oral | Yes | Yes |
Cefadroxil | Oral | No | Yes |
Cefazolin | Injection | Yes | Yes |
Cefdinir | Oral | Yes | Yes |
Cefditoren pivoxil | Oral | Yes | Yes |
Cefepime | Injection | Yes | Yes |
Cefepime and Enmetazobactam | Injection | No | No |
Cefiderocol | Injection | Yes | Yes |
Cefixime | Oral | Yes | No |
Cefoperazone | Injection | Yes | Yes |
Cefotaxime | Injection | Yes | Yes |
Cefotetan | Injection | Yes | Yes |
Cefoxitin | Injection | Yes | Yes |
Cefpodoxime proxetil |
Oral | Yes | No |
Cefprozil | Oral | Yes | Yes |
Ceftaroline fosamil | Injection | Yes | No |
Ceftazidime | Injection | Yes | Yes |
Ceftazidime and avibactam |
Injection | Yes | No |
Ceftibuten | Oral | Yes | Yes |
Ceftobiprole medocaril sodium | Injection | No | No |
Ceftolozane and tazobactam |
Injection | Yes | Yes |
Ceftriaxone | Injection | Yes | Yes |
Cefuroxime axetil | Oral | Yes | No |
Cefuroxime | Injection | Yes | Yes |
Cephalexin | Oral | Yes | No |
Chloramphenicol | Injection | Yes | Yes |
Ciprofloxacin | Oral, Injection | Yes | Yes |
Clarithromycin | Oral | Yes | Yes |
Clindamycin | Injection, Oral | Yes | No |
Clofazimine* | Oral | No | No |
Colistimethate | Injection | Yes | Yes |
Dalbavancin | Injection | Yes | No |
Dapsone* | Oral | No | No |
Daptomycin | Injection | Yes | No |
Delafloxacin | Injection, Oral | No | Yes |
Demeclocycline | Oral | No | Yes |
Dicloxacillin | Oral | Yes | No |
Doripenem | Injection | Yes | Yes |
Doxycycline | Oral, Injection | Yes | Yes |
Eravacycline | Injection | No | Yes |
Ertapenem | Injection | Yes | Yes |
Erythromycin | Oral, Injection | Yes | No |
Erythromycin ethylsuccinate and sulfasoxazole acetyl* |
Oral | No | No |
Ethambutol* | Oral | No | No |
Ethionamide* | Oral | No | No |
Fidaxomicin* | Oral | No | No |
Fosfomycin tromethamine |
Oral | Yes | No |
Gemifloxacin | Oral | Yes | No |
Gentamicin | Injection | Yes | Yes |
Imipenem and cilastatin |
Injection | Yes | Yes |
Imipenem- cilastatin- relebactam |
Injection | Yes | Yes |
Isoniazid* | Oral | No | No |
Isoniazid, Pyrazinamide, and Rifampin* | Oral | No | No |
Kanamycin | Injection | Yes | Yes |
Lansoprazole, Amoxicillin, and Clarithromycin* | Oral | No | No |
Lefamulin | Oral, Injection | Yes | Yes |
Levofloxacin | Oral, Injection | Yes | Yes |
Lincomycin* | Injection | No | No |
Linezolid | Injection, Oral | Yes | No |
Loracarbef | Oral | Yes | Yes |
Meropenem | Injection | Yes | Yes |
Meropenem and vaborbactam |
Injection | Yes | No |
Methenamine Hippurate* |
Oral | No | No |
Metronidazole | Injection, Oral | Yes | No |
Minocycline | Oral, Injection | Yes | Yes |
Moxifloxacin | Oral, Injection | Yes | Yes |
Nafcillin* | Injection | No | No |
Neomycin sulfate* | Oral | No | No |
Nitrofurantoin | Oral | Yes | No |
Ofloxacin | Oral | Yes | Yes |
Omadacycline | Injection, Oral | No | Yes |
Omeprazole magnesium, Amoxicillin, and Rifabutin* | Oral | No | No |
Oritavancin diphosphate |
Injection | Yes | No |
Oxacillin | Injection | Yes | No |
Penicillin | Injection | Yes | No |
Penicillin V | Oral | Yes | No |
Piperacillin and tazobactam |
Injection | Yes | Yes |
Pivmecillinam | Oral | Yes | Yes |
Plazomicin | Injection | Yes | No |
Polymyxin B Sulfate |
Injection | Yes | Yes |
Pretomanid* | Oral | No | No |
Pyrazinamide* | Oral | No | No |
Quinupristin and dalfopristin |
Injection | Yes | Yes |
Rifabutin* | Oral | No | No |
Rifampin | Oral, Injection | Yes | Yes |
Rifapentine* | Oral | No | No |
Rifaximin* | Oral | No | No |
Spectinomycin | Injection | Yes | No |
Streptomycin | Injection | Yes | No |
Sulbactam and Durlobactam | Injection | Yes | No |
Tedizolid | Oral, Injection | Yes | No |
Telavancin | Injection | Yes | No |
Tetracycline | Oral | Yes | Yes |
Ticarcillin and clavulanate |
Injection | Yes | Yes |
Tigecycline | Injection | No | Yes |
Tobramycin | Injection | Yes | Yes |
Trimethoprim hydrochloride |
Oral | Yes | No |
Trimethoprim and sulfamethoxazole |
Oral, Injection | Yes | Yes |
Vancomycin | Injection | Yes | Yes |
Vancomycin* | Oral | No | No |
*No STIC are recognized by FDA for this drug at this time.