Available Isolates and Antimicrobial Susceptibility Testing

At a glance

Isolates for Active Bacterial Core surveillance (ABCs) pathogens are available upon request by year with certain demographic and clinical data and laboratory testing results. Information on antimicrobial susceptibility is also available for three pathogens.

Part of the antimicrobial susceptibility testing chart

Isolate Request Process

CDC isolate bank custodians review requests for isolates prior to approval and release.

There may be a cost associated with isolate requests from for-profit institutions. All requestors are required to pay shipping fees.

Keep Reading: Isolate and Data Requests

Isolates available as of June 3, 2024

Isolates are available between 1995–2021 with certain demographic and clinical data and laboratory testing results.

Age groups: < 1 year, 1 year, 2–4 years, 5–17 years, 18–34 years, 35–49 years, 50–64 years, ≥ 65 years

Infection type/syndrome:

  • Cellulitis
  • Bacteremia without focus
  • Pneumonia
  • Necrotizing fasciitis
  • Streptococcal toxic shock syndrome
  • Other infection type/syndrome

Source:

  • Cerebrospinal fluid
  • Blood
  • Other sterile site

Laboratory testing results:

  • emm type
  • Presence or absence of serum opacity factor
  • Minimum inhibitory concentration for select antibiotics (see table below)

Age groups: < 1 year, 1 year, 2–4 years, 5–17 years, 18–34 years, 35–49 years, 50–64 years, ≥ 65 years

Additional age groupings available for young infant cases <90 days old:

  • Early-onset disease (0–6 days)
  • Late-onset disease (7–89 days)

Infection type/syndrome:

  • Bacteremia without focus
  • Meningitis
  • Pneumonia
  • Other infection type/syndrome

Source:

  • Cerebrospinal fluid
  • Blood
  • Other sterile site

Laboratory testing results:

  • Serotype
  • Minimum inhibitory concentration for select antibiotics (see table below)

Age groups: < 1 year, 1 year, 2–4 years, 5–17 years, 18–34 years, 35–49 years, 50–64 years, ≥ 65 years

Infection type/syndrome:

  • Bacteremia without focus
  • Meningitis
  • Pneumonia
  • Other infection type/syndrome

Source:

  • Cerebrospinal fluid
  • Blood
  • Other sterile site

Laboratory testing result: Serotype

Age groups: < 1 year, 1 year, 2–4 years, 5–17 years, 18–34 years, 35–49 years, 50–64 years, ≥ 65 years

Infection type/syndrome:

  • Bacteremia without focus
  • Meningitis
  • Other infection type/syndrome

Source:

  • Cerebrospinal fluid
  • Blood
  • Other sterile site

Laboratory testing results: Serogroup

Age groups: < 1 year, 1 year, 2–4 years, 5–17 years, 18–34 years, 35–49 years, 50–64 years, ≥ 65 years

Infection type/syndrome:

  • Bacteremia without focus
  • Meningitis
  • Pneumonia
  • Other infection type/syndrome

Source:

  • Cerebrospinal fluid
  • Blood
  • Other sterile site

Laboratory testing results:

  • Serotype
  • Minimum inhibitory concentration for select antibiotics (see table below)

Isolate antimicrobial susceptibility testing

Minimum inhibitory concentration (MIC) of antibiotics are

  • Determined by phenotypic antimicrobial susceptibility testing (AST)
  • Inferred from whole-genome sequencing (WGS)

MIC results were determined

  • Prior to 2015: Solely on AST results from phenotypic testing
  • In 2015: Using both phenotypic- and WGS-based methods
  • From 2016 through present: Primarily inferred from WGS (conventional MIC testing is performed on selected isolates)
Isolate antimicrobial susceptibility testing
Antibiotic Group A Streptococcus Group B Streptococcus Streptococcus pneumoniae
Amoxicillin 3 3 2
Ampicillin 2 2 3
Cefazolin 2* 2* 3
Cefotaxime 1 1 1
Cefoxitin 2* 2* 3
Ceftizoxime 2* 2* 3
Ceftriaxone 2 2 2
Cefuroxime 3 3 2
Chloramphenicol 2 2 2
Clindamycin 1 1 2
Doxycycline 3 3 2
Dtest: ERY/CM 2 2 2
Erythromycin 1 1 1
Levofloxacin 2 2 1
Linezolid 2 2 2
Meropenem 2 2 2
Penicillin 1 1 1
Rifampin 2* 2* 2
Synercid 2 2 2
Tetracycline 1 2 1
Trimethoprim/Sulfamethoxasole 2* 2* 1
Vancomycin 1 1 1
Isolate antimicrobial susceptibility testing key
1 Results are aggregated and publicly available in BactFacts Interactive and/or surveillance reports
2 Results are not routinely reported to the public
2* Results don't have Clinical and Laboratory Standards Institute (CLSI) breakpoints
3 Not routinely tested for the pathogen

Resource

CDC & FDA Antibiotic Resistance (AR) Isolate Bank
Additional isolate resource for other non-ABCs pathogens

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Content Source:
National Center for Immunization and Respiratory Diseases; Division of Bacterial Diseases