TB genotyping is a laboratory-based approach used to analyze the genetic material (e.g., DNA) of Mycobacterium tuberculosis, the bacterium that cause TB disease. The total genetic content is referred to as the genome. Specific sections of the M. tuberculosis genome form distinct genetic patterns that help distinguish different strains of M. tuberculosis.
Why use TB genotyping?
TB genotyping results, when combined with epidemiologic data, help identify persons with TB disease involved in the same chain of recent transmission. In the same way, TB genotyping helps distinguish between persons whose TB disease is the result of TB infection that was acquired in the past, as compared to recently or newly acquired infection with development of TB disease. TB genotyping is a tool that can add value to conventional contact investigation.
Since TB prevention and control efforts directed at preventing TB transmission are fundamentally different from efforts to prevent activation of latent TB infection, genotyping offers a powerful tool to help direct the application of appropriate efforts. Furthermore, TB genotyping allows us to monitor our progress toward eliminating TB transmission more accurately.
- Tuberculosis WGS Training ModuleCdc-pdf In 2018, CDC’s Division of TB Elimination (DTBE) began universal whole-genome sequencing (WGS) (i.e., sequencing an M. tuberculosis isolate for each U.S. case of culture-confirmed TB). Increasingly, state and local programs are using results of WGS and phylogenetic analyses to help guide TB cluster and outbreak investigations. A training module on “Whole-genome sequencing for investigation of recent TB transmission in the United States: Current uses and future plans” is available here.
- Prioritizing Tuberculosis Genotype Clusters for Further Investigation and Public Health ActionCdc-pdf Routine, systematic review of clusters of TB cases with matching genotypes can help determine which clusters to prioritize for public health action. This guidance document can assist state and local TB programs in developing policies and procedures for prioritizing TB genotype clusters for further investigation. Prioritization is especially important for jurisdictions where investigating all TB genotype clusters may be too resource intensive.
- TB Genotyping (Fact sheet)
- Introduction to TB Genotyping (slide set)
- Best Practices for Genotyping-Based Tuberculosis Outbreak DetectionCdc-pdf(PDF – 582KB)
- Tuberculosis Genotyping in the United States 2004 – 2010Cdc-pdf (PDF – 6.3M)
- Genotyping Laboratory Information
- Guide to the Application of Genotyping to Tuberculosis Prevention and Control (June 2004)This provides an introduction to the application of TB genotyping to TB control practices and to the CDC TB Genotyping Program. It is intended for TB controllers, epidemiologists, laboratorians, and other program staff members who will be involved in submitting isolates for genotyping, analyzing and responding to genotyping results, or using genotyping data to monitor TB transmission trends.
TB Genotyping Information Management System (TB GIMS)
The TB Genotyping Information Management System (TB GIMS) is a secure web-based system designed to improve access and dissemination of genotyping information nationwide. TB GIMS was released in March 2010.