Molecular Detection for Tuberculosis Drug Resistance [A Test in Focus]

This whole genome sequencing (WGS) testing provides molecular detection of well-characterized drug-resistance variants in Mycobacterium tuberculosis complex by sequencing Mycobacterium tuberculosis isolates. It is intended to aid in the detection of resistance to first- and second-line antituberculous agents including isoniazid, rifampin, ethambutol, pyrazinamide, the fluoroquinolones (moxifloxacin and ofloxacin) and the aminoglycosides (streptomycin, kanamycin, and amikacin). This testing evaluates selected genes of interest including:

Drug/Drug ClassGenes
IsoniazidahpC, fabG1, inhA, katG
RifampinrpoB
EthambutolembB
PyrazinamidepncA
FluoroquinolonesgyrA
Aminoglycosideseis, gidB, rpsL, rrs

Nancy Wengenack, Ph.D. gives an overview of this test available through Mayo Clinic Laboratories. She discusses when this testing should be ordered, how this testing compares to other testing approaches, and what clinical action can be taken due to the results of this testing.

Testing

Mycobacterium tuberculosis Complex, Molecular Detection of Drug Resistance Markers, Whole Genome Sequencing, Varies (Mayo ID: TBNGS)

Useful for:

Molecular detection of drug resistance variants in culture isolates of the Mycobacterium tuberculosis complex

May provide a more rapid detection of drug resistance than phenotypic, broth-based testing

Aiding in the resolution of discrepant results obtained using phenotypic methods testing for Mycobacterium tuberculosis isolates that are not sufficiently viable to allow for culture-based testing

Specimen Requirements

Supplies: Infectious Container, Large (T146)

Specimen Type: Mycobacterium tuberculosis complex isolate growing in pure culture. Isolates older than 5 weeks or not in a pure culture may require subculture for fresh, isolated growth so the turnaround time for results may be delayed.

Container/Tube: Middlebrook (7H10 or 7H11) medium slant; growth in broth medium (eg, Mycobacteria Growth Indicator Tube [7H9] broth) or on a Lowenstein-Jensen medium slant can be sent but turnaround time for results may be delayed because subculture to Middlebrook agar medium may be required. Organisms received in mixture may result in additional charges for isolation and identification.

Specimen Volume: Isolate with visible growth on solid media; if broth is sent, > or =3 mL of broth culture required.

Collection Instructions: 

  1. Organism must be in pure culture, actively growing. Do not submit mixed cultures.
  2. Place specimen in a large infectious container (T146) and label as an etiologic agent/infectious substance.

Special Instructions: Infectious Specimen Shipping Guidelines

Performance Information

Day(s) and Time(s) Performed

Tuesday, Thursday

Analytic Time

7–14 days

Emily Linginfelter

Emily Linginfelter

Emily Linginfelter is a Marketing Associate at Mayo Clinic Laboratories. She supports marketing strategies for product management and specialty testing. Emily has worked at Mayo Clinic since 2018.