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Test ID: MTBPZ Mycobacterium tuberculosis Complex, Pyrazinamide Resistance by pncA DNA Sequencing, Varies

Infectious

Reporting Name

Mtb PZA Resistance, pncA Sequencing

Useful For

Detection of genotypic resistance to pyrazinamide by Mycobacterium tuberculosis complex isolates

Specimen Type

Varies


Shipping Instructions


1. See Infectious Specimen Shipping Guidelines in Special Instructions.

2. Place specimen in a large infectious container (T146) and label as an etiologic agent/infectious substance.



Necessary Information


Specimen source and suspected organism identification are required.



Specimen Required


Specimen Type: Organism

Supplies: Infectious Container, Large (T146)

Container/Tube: Middlebrook 7H10 agar slant

Specimen Volume: Isolate

Collection Instructions: Organism must be in pure culture, actively growing.


Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Ambient (preferred)
  Refrigerated 

Reference Values

Pyrazinamide resistance not detected

Day(s) Performed

Varies

Test Classification

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

87153-Mtb PZA Confirmation, pncA Sequence

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MTBPZ Mtb PZA Resistance, pncA Sequencing 46245-7

 

Result ID Test Result Name Result LOINC Value
MTBPZ Mtb PZA Resistance, pncA Sequencing 46245-7

Clinical Information

The protein product of the Mycobacterium tuberculosis complex pncA gene is an enzyme that is responsible for activation of the prodrug pyrazinamide (PZA). DNA sequencing of the Mycobacterium tuberculosis complex pncA gene can be used to detect mutations that correlate with in vitro PZA resistance.(1,2) The sequencing result can be available in as little as 1 day after the Mycobacterium tuberculosis complex isolate grows in culture, thereby providing a more rapid susceptibility result than the average 10 to 14 days required by phenotypic broth methods.

Interpretation

Polymorphisms in the pncA gene that have been previously correlated in our laboratory with pyrazinamide (PZA) resistance will be reported as "Mutation was detected in pncA suggesting resistance to pyrazinamide."

 

Wild-type pncA or a silent pncA gene polymorphism (ie, no change in the amino acid translation) will be reported as "No mutation was detected in pncA."

 

New polymorphisms in the pncA gene that have not previously been seen in our laboratory will require additional testing using a reference broth method to determine their correlation with PZA resistance.

Clinical Reference

1. Somoskovi A, Dormandy J, Parson LM, et al: Sequencing of the pncA Gene in members of the Mycobacterium tuberculosis complex has important diagnostic applications: identification of a species-specific pncA mutation in "Mycobacterium canettii" and the reliable and rapid predictor of pyrazinamide resistance. J Clin Microbiol 2007;45:595-599

2. Dormandy J, Somoskovi A, Kreiswirth BN, et al: Discrepant results between pyrazinamide susceptibility testing by the reference BACTEC 460TB method and pncA DNA sequencing in patients infected with multi-drug resistant W-Beijing Mycobacterium tuberculosis strains. Chest 2007;131:497-501

3. Somoskovi A, Parson LM, Salfinger M: The molecular basis of resistance to isoniazid, rifampin, and pyrazinamide in Mycobacterium tuberculosis. Respir Res 2001;2:164-168

Report Available

7 to 21 days

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
MTBVP Mtb PZA Confirmation, pnc A Sequence No, (Bill Only) No

Testing Algorithm

When this test is ordered, the reflex test may be performed and charged.

Method Name

DNA Sequencing

Forms

If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.

Mayo Clinic Laboratories | Microbiology and Infectious Disease Catalog Additional Information:

mml-mycobacteria