Approach

To maximise effectiveness of antibiotic therapy and avoid the development of resistance, combination therapy is essential.

Mycobacterium avium complex (MAC) pulmonary disease

For MAC pulmonary disease, treatment recommendations take into consideration the severity of disease as well as the radiographical appearance.

For mild to moderate nodular bronchiectatic disease, intermittent, treatment with a macrolide (azithromycin or clarithromycin) plus ethambutol plus rifampicin or rifabutin is recommended.[39]​ Azithromycin has fewer drug interactions and may be better tolerated than clarithromycin. Macrolides have rarely been associated with altered cardiac conduction (e.g., QT interval prolongation, arrhythmias including torsades de pointes). For cavitary disease, the recommended regimen consists of the same drugs, but given daily rather than intermittently. Furthermore, the US guidelines recommend the addition of a parenteral aminoglycoside (amikacin or streptomycin) for the initial 2 to 3 months in cavitary or advanced/severe bronchiectatic or macrolide-resistant MAC pulmonary disease.[39][40]​ Aminoglycosides are associated with ototoxicity and nephrotoxicity, and monitoring of serum drug levels and renal function is recommended.

Patients will require treatment until sputum cultures are consecutively negative for at least 12 months.[39]

The addition of amikacin liposomal inhalation is recommended for patients who have failed therapy after at least 6 months of guideline-based therapy.[39]

Lung resection (lobectomy/pneumonectomy) may be considered in patients:

  • With localised disease, especially upper lobe cavitary disease

  • Who failed to convert the sputum culture to negative after 6 months of continuous medical therapy

  • Who cannot tolerate medical therapy.

Surgical excision is an option for patients who have localised disease and who have either failed or not tolerated medical therapy, provided that a surgical team experienced in such procedures is available.

MAC disseminated disease

A macrolide (clarithromycin or azithromycin) plus ethambutol form the cornerstone of therapy. Azithromycin can be substituted for clarithromycin where drug interactions and/or tolerability are an issue. A third or fourth drug may be added in patients with advanced immunosuppression (CD4 count <50 cells/microlitre) or high mycobacterial load, or in the absence of effective antiretroviral therapy (ART). Options for the third or fourth drug may include rifabutin, a fluoroquinolone (e.g., levofloxacin or moxifloxacin), or an injectable aminoglycoside (e.g., amikacin or streptomycin).[8]

Systemic fluoroquinolone antibiotics may cause serious, disabling, and potentially long-lasting or irreversible adverse events. These include, but is not limited to: tendinopathy/tendon rupture; peripheral neuropathy; arthropathy/arthralgia; aortic aneurysm and dissection; heart valve regurgitation; dysglycaemia; and central nervous system effects including seizures, depression, psychosis, and suicidal thoughts and behaviour.[41]

  • Prescribing restrictions apply to the use of fluoroquinolones, and these restrictions may vary between countries. In general, fluoroquinolones should be restricted for use in serious, life-threatening bacterial infections only. Some regulatory agencies may also recommend that they must only be used in situations where other antibiotics, that are commonly recommended for the infection, are inappropriate (e.g., resistance, contraindications, treatment failure, unavailability).

  • Consult your local guidelines and drug formulary for more information on suitability, contraindications, and precautions.

In patients with HIV infection, treatment is discontinued after a course of at least 12 months in patients who remain asymptomatic with respect to MAC signs and symptoms and have a sustained increase in their CD4 T-lymphocyte counts to over 100 cells/microlitre for longer than 6 months.

HIV-infected patients need to be on effective ART.

Attention needs to be paid to drug interactions between antiretroviral drugs: in particular, protease inhibitors and non-nucleoside reverse transcriptase inhibitors and rifamycins (rifabutin and rifampicin).[8]

Consult your local drug information source for detailed information on drug interactions.

MAC lymphadenitis

Treatment is with prompt total surgical excision of the involved lymph nodes. If extensive disease, or poor response to surgical therapy, antimycobacterial therapy can be initiated.[30]

MAC hypersensitivity pneumonitis

Abstinence from hot tubs is adequate for many.

Prednisolone tapered over 4 to 8 weeks is the treatment of choice. Antimycobacterial drugs may be needed if extensive disease and symptoms progress, although the use of these is still debated.[30]

Macrolide-resistant MAC

The treatment of macrolide-resistant MAC disease is complex, and a specialist experienced in MAC therapy should be consulted before therapy is started. Guidelines suggest that extensive use of additional agents before referral to a specialist may compromise the patient's chance for an optimal therapeutic response; therefore, prompt referral is important.[39]

Use of this content is subject to our disclaimer