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Disseminated Mycobacterium avium Complex (MAC) Infection


General Information


  • disseminated multiorgan disease caused by nontuberculous mycobacteria M. avium , M. intracellulare , and M. chimaera1,2
  • opportunistic infection typically seen in patients with1,2,3
    • HIV infection with < 50 CD4 T cells/mcL
    • hematopoietic stem cell or solid organ transplants
    • chronic corticosteroid use
    • hairy cell leukemia or other hematologic malignancies
    • genetic defects in interferon-gamma or interleukin-12 pathways
  • species differentiation not clinically relevant1

Also called

  • MAC infection
  • Mycobacterium avium-intracellulare complex infection
  • MAI infection
  • DMAC


General references used

  1. Griffith DE, Aksamit T, Brown-Elliott BA, et al. An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases. Am J Respir Crit Care Med. 2007 Feb 15;175(4):367-416OpenInNew, correction in Am J Respir Crit Care Med 2007 Apr 1;175(7):744, commentary can be found in Am J Respir Crit Care Med 2007 Aug 15;176(4):418OpenInNew
  2. Corti M, Palmero D. Mycobacterium avium complex infection in HIV/AIDS patients. Expert Rev Anti Infect Ther. 2008 Jun;6(3):351-63OpenInNew
  3. Henkle E, Winthrop KL. Nontuberculous mycobacteria infections in immunosuppressed hosts. Clin Chest Med. 2015 Mar;36(1):91-9OpenInNew
  4. Egelund EF, Fennelly KP, Peloquin CA. Medications and Monitoring in Nontuberculous Mycobacteria Infections. Clin Chest Med. 2015 Mar;36(1):55-66OpenInNew
  5. Panel on Opportunistic Infections in HIV-Infected Adults and Adolescents. Guidelines for the prevention and treatment of opportunistic infections in HIV-infected adults and adolescents: recommendations from the Centers for Disease Control and Prevention, the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America. AIDSinfo 2018 May 29OpenInNewPDFPictureAsPdf

Recommendation grading systems used

  • American Thoracic Society/Infectious Disease Society of America (ATS/IDSA) rating system adapted from Infectious Disease Society/United States Public Health Service rating system
    • strength of recommendation
      • Grade A - good evidence to support recommendation for use
      • Grade B - moderate evidence to support recommendation for use
      • Grade C - poor evidence to support recommendation for or against use
      • Grade D - moderate evidence to support recommendation against use
      • Grade E - good evidence to support recommendation against use
    • quality of evidence
      • Level I - evidence from at least 1 properly randomized, controlled trial
      • Level II - evidence from at least 1 well-designed clinical trial without randomization, from cohort or case-controlled analytic studies (preferably from more than 1 center), from multiple time-series studies or from dramatic results in uncontrolled experiments
      • Level III - evidence from opinion of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees
  • Centers for Disease Control and Prevention/National Institutes of Health/HIV Medicine Association of Infectious Diseases Society of America (CDC/NIH/IDSA) grading system for recommendations
    • strength of recommendation
      • A - strong recommendation for the statement
      • B - moderate recommendation for the statement
      • C - optional recommendation
    • quality of evidence for recommendation
      • I - 1 or more randomized trials with clinical outcomes and/or validated laboratory endpoints
      • II - 1 or more well-designed, nonrandomized trials or observational cohort studies with long-term clinical outcomes
      • III - expert opinion

Synthesized Recommendation Grading System for DynaMed

  • DynaMed systematically monitors clinical evidence to continuously provide a synthesis of the most valid relevant evidence to support clinical decision-making (see 7-Step Evidence-Based MethodologyOpenInNew).
  • Guideline recommendations summarized in the body of a DynaMed topic are provided with the recommendation grading system used in the original guideline(s), and allow DynaMed users to quickly see where guidelines agree and where guidelines differ from each other and from the current evidence.
  • In DynaMed (DM), we synthesize the current evidence, current guidelines from leading authorities, and clinical expertise to provide recommendations to support clinical decision-making in the Overview & Recommendations section.
  • We use the Grading of Recommendations Assessment, Development and Evaluation (GRADE)OpenInNew to classify synthesized recommendations as Strong or Weak.
    • Strong recommendations are used when, based on the available evidence, clinicians (without conflicts of interest) consistently have a high degree of confidence that the desirable consequences (health benefits, decreased costs and burdens) outweigh the undesirable consequences (harms, costs, burdens).
    • Weak recommendations are used when, based on the available evidence, clinicians believe that desirable and undesirable consequences are finely balanced, or appreciable uncertainty exists about the magnitude of expected consequences (benefits and harms). Weak recommendations are used when clinicians disagree in judgments of relative benefit and harm, or have limited confidence in their judgments. Weak recommendations are also used when the range of patient values and preferences suggests that informed patients are likely to make different choices.
  • DynaMed (DM) synthesized recommendations (in the Overview & Recommendations section) are determined with a systematic methodology:
    • Recommendations are initially drafted by clinical editors (including ≥ 1 with methodological expertise and ≥ 1 with content domain expertise) aware of the best current evidence for benefits and harms, and the recommendations from guidelines.
    • Recommendations are phrased to match the strength of recommendation. Strong recommendations use "should do" phrasing, or phrasing implying an expectation to perform the recommended action for most patients. Weak recommendations use "consider" or "suggested" phrasing.
    • Recommendations are explicitly labeled as Strong recommendations or Weak recommendations when a qualified group has explicitly deliberated on making such a recommendation. Group deliberation may occur during guideline development. When group deliberation occurs through DynaMed-initiated groups:
      • Clinical questions will be formulated using the PICO (Population, Intervention, Comparison, Outcome) framework for all outcomes of interest specific to the recommendation to be developed.
      • Systematic searches will be conducted for any clinical questions where systematic searches were not already completed through DynaMed content development.
      • Evidence will be summarized for recommendation panel review including for each outcome, the relative importance of the outcome, the estimated effects comparing intervention and comparison, the sample size, and the overall quality rating for the body of evidence.
      • Recommendation panel members will be selected to include at least 3 members that together have sufficient clinical expertise for the subject(s) pertinent to the recommendation, methodological expertise for the evidence being considered, and experience with guideline development.
      • All recommendation panel members must disclose any potential conflicts of interest (professional, intellectual, and financial), and will not be included for the specific panel if a significant conflict exists for the recommendation in question.
      • Panel members will make Strong recommendations if and only if there is consistent agreement in a high confidence in the likelihood that desirable consequences outweigh undesirable consequences across the majority of expected patient values and preferences. Panel members will make Weak recommendations if there is limited confidence (or inconsistent assessment or dissenting opinions) that desirable consequences outweigh undesirable consequences across the majority of expected patient values and preferences. No recommendation will be made if there is insufficient confidence to make a recommendation.
      • All steps in this process (including evidence summaries which were shared with the panel, and identification of panel members) will be transparent and accessible in support of the recommendation.
    • Recommendations are verified by ≥ 1 editor with methodological expertise, not involved in recommendation drafting or development, with explicit confirmation that Strong recommendations are adequately supported.
    • Recommendations are published only after consensus is established with agreement in phrasing and strength of recommendation by all editors.
    • If consensus cannot be reached then the recommendation can be published with a notation of "dissenting commentary" and the dissenting commentary is included in the topic details.
    • If recommendations are questioned during peer review or post publication by a qualified individual, or reevaluation is warranted based on new information detected through systematic literature surveillance, the recommendation is subject to additional internal review.

DynaMed Editorial Process

Special acknowledgements

  • DynaMed topics are written and edited through the collaborative efforts of the above individuals. Deputy Editors, Section Editors, and Topic Editors are active in clinical or academic medical practice. Recommendations Editors are actively involved in development and/or evaluation of guidelines.
  • Editorial Team role definitions
    Topic Editors define the scope and focus of each topic by formulating a set of clinical questions and suggesting important guidelines, clinical trials, and other data to be addressed within each topic. Topic Editors also serve as consultants for the internal DynaMed Editorial Team during the writing and editing process, and review the final topic drafts prior to publication.
    Section Editors have similar responsibilities to Topic Editors but have a broader role that includes the review of multiple topics, oversight of Topic Editors, and systematic surveillance of the medical literature.
    Recommendations Editors provide explicit review of DynaMed Overview and Recommendations sections to ensure that all recommendations are sound, supported, and evidence-based. This process is described in "Synthesized Recommendation Grading."
    Deputy Editors are employees of DynaMed and oversee DynaMed internal publishing groups. Each is responsible for all content published within that group, including supervising topic development at all stages of the writing and editing process, final review of all topics prior to publication, and direction of an internal team.

How to cite

National Library of Medicine, or "Vancouver style" (International Committee of Medical Journal Editors):

  • DynaMed [Internet]. Ipswich (MA): EBSCO Information Services. 1995 - . Record No. T116948, Disseminated Mycobacterium avium Complex (MAC) Infection; [updated 2018 Nov 30, cited place cited date here]. Available from Registration and login required.
  • KeyboardArrowRight

    Overview and Recommendations

    • Background

    • Evaluation

    • Management

    • Prevention

  • Related Summaries

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    General Information

    • Description

    • Also called

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    • Incidence/Prevalence

    • Risk factors

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    Etiology and Pathogenesis

    • Pathogen

    • Transmission

    • Pathogenesis

    • Immune response

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    History and Physical

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      • Chief concern (CC)

      • History of present illness (HPI)

    • Physical

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    • Making the diagnosis

    • Differential diagnosis

    • Testing overview

    • General laboratory testing

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      Microbiologic testing

      • Specimen collection

      • Smear for acid-fast bacilli (AFB)

      • Culture

      • Species identification

      • Antimicrobial susceptibility testing

    • Imaging studies

    • Other diagnostic testing

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    • Management overview

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      • Recommendations

      • Efficacy

      • Selected adverse effects of antimicrobials

      • Considerations for patients with HIV

      • Treatment failure

    • Follow-up

  • KeyboardArrowRight

    Complications and Prognosis

    • Complications

    • Prognosis

  • KeyboardArrowRight

    Prevention and Screening

    • KeyboardArrowRight


      • Recommendations

      • Efficacy

      • Discontinuation

      • Limiting environmental exposure

    • Screening

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    Guidelines and Resources

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      • United States guidelines

      • United Kingdom guidelines

      • Asian guidelines

    • Review articles

    • MEDLINE search

  • Patient Information

  • KeyboardArrowRight

    ICD Codes

    • ICD-10 codes

  • KeyboardArrowRight


    • General references used

    • Recommendation grading systems used

    • Synthesized Recommendation Grading System for DynaMed

    • DynaMed Editorial Process

    • Special acknowledgements

    • How to cite

Topic Editor
Renee Ridzon MD

Adjunct Associate Professor, Boston University School of Public Health; Massachusetts, United States

Conflicts of Interest

Dr. Ridzon declares no relevant financial conflicts of interest.

Recommendations Editor
Esther Jolanda van Zuuren MD

Head of Allergy, Dermatology, and Venereology, Leiden University Medical Centre; Netherlands

Conflicts of Interest

Dr. van Zuuren declares no relevant financial conflicts of interest.

Deputy Editor
Alan Ehrlich MD, FAAFP

Executive Editor, DynaMed; Associate Professor of Family Medicine, University of Massachusetts Medical School; Massachusetts, United States

Conflicts of Interest

Dr. Ehrlich declares no relevant financial conflicts of interest.

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