Mycobacterium avium complex infection

Last updated: November 1, 2023

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Summarytoggle arrow icon

Mycobacterium avium complex (MAC) infection is caused by the Mycobacterium avium complex (M. avium and M. intracellulare). It more commonly occurs in patients with advanced immunosuppression and is considered an AIDS-defining condition. Diagnosis is based on isolation of the organism (acid-fast bacilli) on culture and treatment consists of at least two anti-mycobacterial drugs (e.g., a macrolide with ethambutol).

Etiologytoggle arrow icon

References: [2]

Clinical featurestoggle arrow icon

MAC infection often manifests as disseminated disease and typically occurs in patients with advanced immunosuppression (CD4 counts < 50). [2]

Diagnosticstoggle arrow icon

Diagnosis of disseminated MAC is based on isolation of the organism in a patient with characteristic clinical features. [2]

Disseminated MAC may mimic disseminated TB. Findings that favor MAC include elevated alkaline phosphatase and gamma-glutamyl transpeptidase, hepatosplenomegaly, and leukopenia. [3]

Treatmenttoggle arrow icon

Manage all patients in consultation with an infectious disease specialist. In patients with HIV, initiate ART (if not already started) concurrently with MAC treatment.

Referencestoggle arrow icon

  1. $Contributor Disclosures - Mycobacterium avium complex infection. None of the individuals in control of the content for this article reported relevant financial relationships with ineligible companies. For details, please review our full conflict of interest (COI) policy: URL:
  2. Guidelines for the Prevention and Treatment of Opportunistic Infections in Adults and Adolescents with HIV. Updated: August 18, 2020. Accessed: December 18, 2020.
  3. Karakousis PC, Moore RD, Chaisson RE. Mycobacterium avium complex in patients with HIV infection in the era of highly active antiretroviral therapy. Lancet Infect Dis. 2004; 4 (9): p.557-565.doi: 10.1016/s1473-3099(04)01130-2 . | Open in Read by QxMD

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