Isolate Bank – C. difficile Infection Tracking

Overview

The C. difficile Isolate Bank is a collection of isolates obtained through the C. difficile infection (CDI) Surveillance Program. This program is a population- and laboratory-based surveillance system operating in ten EIP sites. It draws from a population of roughly 12 million people, and it launched in 2009.

How the Isolate Bank receives samples

Stool aliquots or stool swabs are sent to partner reference laboratories for culture. C. difficile isolates obtained from these cultures are sent to CDC for molecular typing and characterization by whole genome sequencing including:

• Multilocus sequence typing (MLST).
• Detection of tcdA, tcdB, cdtA and cdtB toxin genes.
• Assessment of deletions in the tcdC gene.

Isolates currently available

• C. difficile isolates from a subset of cases in EIP sites, collected since 2009.
• A panel of 30 highly characterized C. difficile isolates that represent the ten most prevalent PCR ribotypes, collected in 2016. Made available through the CDC & FDA Antibiotic Resistance Isolate Bank (AR Isolate Bank).
• A sample of C. difficile isolates (based on geographic distribution across the EIP sites) collected during 2010-2011. Made available through BEI Resources and includes the following metadata for all isolates:
  • Basic demographic information.
  • Year of specimen collection.
  • Geographical region.
  • Hospitalization.
  • Outcome.
  • Epidemiologic classification.
  • Molecular data.

Requesting isolates

Requesting isolates from AR Isolate Bank and BEI Resources

• Request isolates from AR Isolate Bank and BEI Resources using the AR Isolate Bank ordering platform and BEI Resources ordering platform.
• If isolates from the above sources do not meet researchers' needs, additional isolates can be requested from CDC using the process below.

Requesting isolates from CDC

1. Verify if the isolates you need are available by sending a short request (3-5 sentences) to HAIC@cdc.gov that includes:
   1. The number of isolates needed.
   2. Associated specific epidemiologic data needed.
2. If CDC confirms availability, submit a formal request, no longer than 2 pages, to HAIC@cdc.gov. This formal request should be a summary of the proposed project, on an official letterhead, which includes the following information:
   1. Objective of the project.
   2. Public health importance.
   3. Scientific methods.
   4. Authorship plans.
   5. Confidentiality.
   6. Biohazard issues.
   7. Projected timelines.
   8. Requestor's current association or affiliation and complete contact information.
   9. Number of isolates needed and associated specific epidemiologic data.
   10. Shipping account number.
3. CDC will send a User Fee Agreement for you or other researchers to sign.
4. Pay user fee, if applicable.

Following these steps, CDC then sends isolates to the requestor.

Requirements of use

Prohibited uses

• Duplicate activities already conducted as part of “core” CDI surveillance project activities.
• Duplicate already-approved projects for which permission is granted to another investigator.

How CDC ensures proper use

• Sharing all isolate requests with the appropriate CDC and EIP site staff for approval by email.
• Notifying the requestor if the request is approved or denied.
• Requiring requestors to submit modifications to their initially proposed use of isolates for approval.

User fee agreement

CDC will send a User Fee agreement for completion. The document outlines and requires agreement on:

• The limit on the distribution of isolates.
• The source of these isolates.
• The stated use of isolates detailed in the original request.
• Standardized format when acknowledging EIP CDI surveillance: Centers for Disease Control and Prevention's Emerging Infections Program Clostridioides difficile infection (CDI) surveillance.
• Requestor to share any abstracts or manuscripts containing EIP isolate data with CDC prior to submission to scientific conferences or peer-reviewed journals. This is to ensure that the EIP CDI Surveillance Program has been appropriately acknowledged, and that the use of the isolates is consistent with the proposal submitted by the requestor.

Fees for approved requests

• For-profit institutions: $150 per isolate.
• Non-profit institutions requesting 11 or more isolates: $50 per isolate.
• Non-profit institutions requesting 10 or fewer isolates: free of charge.

Contacts

For all questions, please email HAIC@cdc.gov.