MYCOBACTERIOLOGY - TB GENOTYPING
The Wyoming Public Health Laboratory (WPHL) has recently been approved by the Centers for Disease Control and Prevention (CDC) to participate in the CDC Tuberculosis Genotyping Program. Genotyping methods at the molecular level will allow further classification of Mycobacterium tuberculosis isolates, the causative agent of tuberculosis, and will enhance the epidemiological capacity for the TB Program.
WPHL Quick Reference Downloadable Forms
TB Genotyping Isolate Submission Form
TB Genotyping Isolate Submission Protocol
Supply Order Form
What is Genotyping?
Genotyping can potentially determine the origin of a TB strain. If two patients have isolates with the same genotype, they would be considered “linked epidemiologically” and most likely became infected from a common source. Wyoming will also be collaborating with surrounding states, which will enable us to detect possible transmissions between patients in other jurisdictions. The recognized benefits of TB genotyping are: enhanced contact investigations, earlier outbreak detection, identifying false positive cultures, and the ability to share TB data with neighboring state public health departments.
Where is Genotyping Done?
The CDC has established the Microbial Diseases Laboratory within the California Department of Health Services in Richmond, California as our reference laboratory. They will be performing three genotyping methods; spoligotyping, mycobacterial interspersed repetitive units (MIRU) analysis, and IS6110-based restriction fragment length polymorphism (RFLP) analysis. Spoligotyping and MIRU will be PCR methods and all isolates will be tested by these two methods. RFLP will be reserved for select isolates that have identical PCR genotypes and may require or benefit from further characterization.
How are laboratories doing testing for Wyoming citizens involved in the TB Genotyping Program?
All laboratories within the State of Wyoming, and all reference laboratories performing cultures for Wyoming patients will be eligible and are encouraged to participate. Isolates must be sent to the WPHL for submission to the genotyping laboratory. There are strict requirements for submission of isolates to the WPHL and the appropriate paperwork must be completed prior to shipment. Turnaround time for reporting to the TB program should be within 10 days of receipt of the isolates unless testing capacity is exceeded or unexpected technical delays are experienced. The genotyping results will be reported to the WDH - TB program, not the submitting laboratory, unless isolates represent false-positive cultures.
Due to the low number of TB cases each year in the state, the WPHL will be sending one isolate from every patient with a culture positive specimen. The database of results will be kept by the TB Program. Submitting laboratories should incur no expenses for participation in this program, and postage paid shipping containers for infectious substances will be provided upon request to the WPHL.
How do we send in an isolate of MTB for Genotyping?
To submit an isolate for genotyping call the WPHL at 307-777-7431 and talk to the mycobacteriologist or the Microbiology Supervisor. Once they have confirmed the isolate meets the requirements for submission, a shipping kit with all necessary supplies and forms will be sent to the submitter.
Cultures must be viable, pure, and identified as M. tuberculosis complex. Broth, in a leak-proof vial or solid medium culture such as LJ, is acceptable. Petri dishes are not acceptable.
Laboratorians can preview the submission protocol and the form from this website.
For additional information on TB Genotyping call the WPHL during business hours at 307-777-7431