Test Catalog

Test ID: TBIDS    
Culture Referred for Identification, Mycobacterium and Nocardia with Antimicrobial Susceptibility Testing, Varies

Method Description Describes how the test is performed and provides a method-specific reference

The Gen-Probe AccuProbe system uses an acridinium-labeled, single-stranded DNA probe that is complementary to the ribosomal RNA of the target organism. After the ribosomal RNA is released from the organism, the labeled DNA probe combines with the target organism's ribosomal RNA to form a stable DNA:RNA hybrid. Chemiluminescence is used as an indicator to detect specific hybrids.(Musial CE, Tice LS, Stockman L, Roberts GD: Identification of Mycobacteria from culture by using Gen-Probe rapid diagnostic system for Mycobacterium avium complex and Mycobacterium tuberculosis complex. J Clin Microbiol. 1988 Oct;26[10]:2120-2123)


The DNA sequence analysis utilizes a 500-base pair region of the 16S rRNA gene as the target for identification of mycobacteria and is performed using the MicroSeq kit from Applied Biosystems. Sequence data generated is compared to several different databases of known mycobacterial and aerobic actinomycete sequences to obtain organism identification. These include MicroSeq, NCBI GenBank, and Mayo Clinic Mycobacteria database. A 100% agreement with a database strain is needed for an acceptable identification to the species level.(Hall L, Doerr KA, Wohlfiel SL, Roberts GD: Evaluation of the MicroSeq system for identification of mycobacteria by 16S ribosomal DNA sequencing and its integration into a routine clinical mycobacteriology laboratory. J Clin Microbiol. 2003 Apr;41[4]:1447-1453)


Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI TOF MS) analysis is done using the Bruker BioTyper platform and the Bruker BDAL library, Bruker Mycobacterial Library, and the Mayo Clinic Library. A spectral score of 2.0 or greater is required for identification to the species level.


The method employed in this assay is broth microtiter dilution using a commercially available plate from Trek Diagnostics. Antimicrobials included in the assay are tested according to the Clinical and Laboratory Standards Institute (CLSI) guidelines.(CLSI: Susceptibility Testing of Mycobacteria, Nocardiae, and Other Aerobic Actinomycetes. 2nd ed. CLSI document M24-A2. CLSI; 2011; Woods GL, Lin SYG, Desmond EP: Susceptibility test methods: Mycobacteria, Nocardia, and Other Actinomycetes. In: Jorgensen JH, Pfaller MA, Carroll KC, et al, eds. Manual of Clinical Microbiology. Vol 1. 11th ed. ASM Press; 2015:1356-1378)


M tuberculosis first-line susceptibilities are tested with the presence of critical concentrations of the antimycobacterial drugs isoniazid, rifampin, and ethambutol. One of 2 FDA-cleared platforms may be used. Second-line susceptibilities utilize the MycoTB broth microtiter dilution plate.(Trek Diagnostic Systems Inc.)


Antimicrobials included in the assay are tested according to the CLSI guidelines. The plate contains lyophilized antimicrobials, which are rehydrated prior to testing. A standardized suspension of the M tuberculosis isolate is added to the plate wells and the plate is incubated at 36 degrees C in 5% to 10% CO2 for up to 14 days. The first drug-containing well with no visible growth is determined to be the endpoint.(CLSI: Susceptibility Testing of Mycobacteria, Nocardiae, and Other Actinomycetes; Approved Standard. CLSI document M24-A2, 2011; Hall L, Jude KP, Clark SL, et al: Evaluation of the Sensititre MycoTB plate for susceptibility testing of the Mycobacterium tuberculosis complex against first- and second-line agents. J Clin Microbiol. 2012;50:3732-3734)

PDF Report Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Sunday

Report Available The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

60 to 70 days

Performing Laboratory Location Indicates the location of the laboratory that performs the test