cobas® MAI

Mycobacterium avium complex (MAC) detection

 

Nontuberculous mycobacteria (NTM) are mycobacterial species other than M. tuberculosis and M. leprae. NTMs are found ubiquitously in the environment, including soil and water. Although NTM can colonise body surfaces and secretions without causing disease, they have been associated with four distinct clinical syndromes; progressive pulmonary disease (MAC, M. kansasii, M. abscessus), superficial lymphadenitis, seen commonly in pediatric populations, (MAC, M. scrofulaceum, M. malmoense), disseminated disease in severely immunocompromised patients, and skin and soft tissue infection usually as a consequence of direct inoculation.1,2 M. avium and M. intracellulare are two closely related, distinct species of nontuberculous mycobacteria (NTM), which comprise the M. avium complex (MAC), and may also be grouped together as M. avium-intracellulare (MAI). MAC is primarily a pulmonary pathogen that affects individuals who are immune compromised (e.g., patients with AIDS, cancer, receiving hematologic and solid organ transplants, or on immunosuppressive chemotherapy).4 NTMs, including MAC, should be identified to species level.1,3 cobas® MAI provides a solution to detect and differentiate M. avium and M. intracellulare DNA in human respiratory specimens providing important information for patient care decisions. This test is intended for use in conjunction with culture as an aid in the diagnosis of M. avium-intracellulare complex (MAC) infection.

cobas MAI The bacteria can be found in places such as:

cobas® MAI is a duplex test designed to detect and differentiate M. avium and M. intracellulare DNA. Selective amplification of target nucleic acid from the sample is achieved by the use of target-specific forward and reverse primer for the M. avium complex which is selected from a highly-conserved region within the respective target organism. MAC is detected by one selective set of primers and M. avium and M. intracellulare are differentiated by two distinct probes within the amplification region.

Molecular diagnostic algorithm

Enabling a complete diagnosis is critical to ensure proper therapy is initiated. When patient presents with symptoms of tuberculosis, the cobas® MTB test is performed. If positive, patient should be evaluated for drug resistance using cobas® MTB-RIF/INH test. If negative, the cobas® MAI test can be used to detect a nontuberculosis infection.

Molecular Diagnostics Algorithm
Intended use

cobas® MAI for use on the cobas® 6800/8800 Systems is an automated, qualitative in vitro diagnostic test, that utilises real-time polymerase chain reaction (PCR), for the direct detection and differentiation of Mycobacterium avium and Mycobacterium intracellulare DNA in human respiratory specimens including inactivated raw sputum, and inactivated digested and decontaminated (N-acetyl-L-cysteine/NaOH [NALC-NaOH]-treated) sputum inactivated, digested and decontaminated (NALC-NaOH-treated) bronchoalveolar lavage (BAL) samples. This test is intended for use in conjunction with culture as an aid in the diagnosis of M. avium-intracellulare complex (MAC) infection.

 

Ordering information

 Material Number

 Product Name

 Tests Per Unit

 08412138190

 cobas® MAI

 384 test cassette

 07544863190

 cobas® MAI Positive Control Kit

 16 controls x 1mL each

 07002238190

 cobas® 6800/8800 Buffer Negative Control Kit

 16 controls x 1mL each

 08185476001

 cobas® Microbial Inactivation Solution

 16 bottles x 30mL each

Registration status

CE-IVD

Package inserts

Access package inserts through your country’s Roche Diagnostics Website.

References

 

 
  1. Griffith DE, Aksamit T, Brown-Elliott BA, et al. An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases. AmericanJ Respir Crit Care Med. 2007;175:367-416.
  2. Center for Disease Control and Prevention. Biosafety in microbiological and biomedical laboratories, 5th ed. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institutes of Health HHS Publication No. (CDC) 21-1112, revised December 2009.
  3. Haworth CS, Floto RA. Introducing the new BTS Guideline: Management of non-tuberculous mycobacterial pulmonary disease (NTM-PD). Thorax. 2017 Nov;72(11):969-970
  4. Henkle E and Winthrop K. Nontuberculous Mycobacteria Infections in Immunosuppressed Hosts. Clin Chest Med. 2015 March ; 36(1): 91–99. Thorax. 2017 Nov;72(11):969-970

Specifications and Analytical Performance

  • Sample Volume

    Sputum ≥ 0.4mL, Sediment ≥ 0.2mL

  • Specimen Types

    Raw Sputum, Sputum Sediment, Bronchoalveolar lavage (BAL)

  • Patient Collection

    Providing sufficient patient sample was collected, the cobas® MAI test can be run in conjunction with cobas® MTB and cobas® MTB-RIF/INH tests without the duplication of the pre-analytic processing

  • Sample Processing

    Manual liquefaction and inactivation followed by sonication and automated amplification and detection on the cobas® 6800/8800 Systems

  • PCR Target Regions

    Selective amplification of target nucleic acid is achieved by the use of target-specific primers for the M. avium complex which is selected from a highly-conserved region within the respective target organism. MAC is detected by one selective set of primers and M. avium and M. intracellulare are differentiated by two distinct probes within the amplification region (16S rRNA gene).

  • Controls

    Internal Control ensures sample validity. Test specific Positive Control and buffer Negative Control ensures run validity.

  • Inclusivity

    The inclusivity for eleven members of the M. avium complex was confirmed by testing a total of 25 strains.

  • Analytical Specificity

    A panel of 173 bacteria, fungi and viruses, including those commonly found in respiratory tract did not interfere with the test by generating false positive results

  • Analytical Sensitivity (Limit of Detection)

    M. intracellulare
        42.5 CFU/mL (sputum/BAL sediment)
        46.6 CFU/mL (raw sputum)
    M. avium
        43.5 CFU/mL (sputum/BAL sediment)
        44.9 CFU/mL (raw sputum)

  • Endogenous Interference

    Not affected by the presence of elevated levels of gastric juice, hemoglobin, human whole blood, human DNA, mucin, pus and saliva

  • Exogenous Interference

    Not affected by the presence of 48 drugs and over-the-counter substances

Clinical Performance
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cobas® 6800 and cobas® 8800 Systems

 

The fully automated cobas 6800/8800 Systems offer the fastest time to results with the highest throughput and the longest walk-away time available among automated molecular platforms, providing laboratories with improved operating efficiency and the flexibility to adapt to changing testing demands.

 

Ready-to-use reagents are stored at appropriate temperatures on the system with their expiration monitored. This enables the complete mycobacteria menu comprising cobas® MTB, cobas® MAI, and cobas® MTB-RIF/INH to be seamlessly run with available menu (HIV, hepatitis, HPV and STI’s) for quality results that help speed proper treatment and reduce the spread of infection.