What is the treatment for atypical mycobacterium (atypical Mycobacterium) lung disease?

From the Guidelines

The treatment for atypical mycobacterium lung disease typically involves a multidrug antibiotic regimen tailored to the specific mycobacterial species and disease severity. For Mycobacterium avium complex (MAC), the most common regimen includes a macrolide (clarithromycin 500-1000 mg daily or azithromycin 250-500 mg daily), ethambutol (15 mg/kg daily), and rifampin (600 mg daily) or rifabutin (300 mg daily) 1. This three-drug combination is usually continued for at least 12 months after sputum cultures become negative, typically resulting in an 18-24 month total treatment duration. Some key points to consider in the treatment of atypical mycobacterium lung disease include:

• For more severe or cavitary disease, an initial phase may include injectable amikacin or streptomycin.
• For M. abscessus, treatment often includes a macrolide plus intravenous medications such as amikacin, imipenem, and cefoxitin during an initial intensive phase, followed by oral medications 1.
• Treatment success requires consistent medication adherence despite common side effects like gastrointestinal disturbances, liver toxicity, and vision changes.
• Regular monitoring of drug levels, liver function, and visual acuity is essential.
• Adjunctive treatments may include airway clearance techniques, bronchoscopy for mucus plugging, and sometimes surgical resection of localized disease.
• Treatment is challenging due to the bacteria's natural antibiotic resistance and biofilm formation in the airways. It's also important to note that the treatment regimen may vary depending on the specific mycobacterial species and disease severity, and that expert consultation is recommended for patients who have difficulty tolerating treatment regimens or who do not respond to therapy 1. Additionally, the most recent guidelines from the British Thoracic Society recommend a multidrug regimen for the treatment of M. abscessus lung disease, including an initial phase with intravenous antibiotics followed by a continuation phase with oral antibiotics 1. The US Cystic Fibrosis Foundation and European Cystic Fibrosis Society also recommend a multidrug regimen for the treatment of NTM lung disease in individuals with cystic fibrosis, including a macrolide, rifampin, and ethambutol for MAC, and a macrolide, amikacin, and cefoxitin or imipenem for M. abscessus 1.

From the FDA Drug Label

Antivirals: Atazanavir Use With Caution Atazanavir: When clarithromycin is co-administered with atazanavir, the dose of clarithromycin should be decreased by 50% [see Clinical Pharmacology (12. 3)]. Since concentrations of 14-OH clarithromycin are significantly reduced when clarithromycin is co-administered with atazanavir, alternative antibacterial therapy should be considered for indications other than infections due to Mycobacterium aviumcomplex. Etravirine Etravirine: Clarithromycin exposure was decreased by etravirine; however, concentrations of the active metabolite, 14-OH-clarithromycin, were increased Because 14-OH-clarithromycin has reduced activity against Mycobacterium aviumcomplex (MAC), overall activity against this pathogen may be altered; therefore alternatives to clarithromycin should be considered for the treatment of MAC

The treatment for atypical mycobacterium lung disease may include clarithromycin, but the dose may need to be adjusted based on concomitant medications, such as atazanavir or etravirine. Alternative antibacterial therapies should be considered for indications other than infections due to Mycobacterium avium complex 2. Clarithromycin is an option, but its effectiveness may be altered when co-administered with certain medications.

From the Research

Treatment for Atypical Mycobacterium Lung Disease

The treatment for atypical mycobacterium lung disease varies depending on the specific type of mycobacterium.

• For Mycobacterium kansasii infection, the current standard of care therapy is isoniazid (300 mg/day), rifampin (600 mg/day), and ethambutol (15 mg/kg/day) for 12 months after achieving sputum culture negativity 3.
• For Mycobacterium avium complex (MAC) lung disease, a regimen consisting of macrolides (clarithromycin or azithromycin) with rifampin and ethambutol has been recommended, and this regimen should be maintained for at least 12 months after negative sputum culture conversion 4.
• Azithromycin-containing regimens have also been shown to be effective in treating MAC lung disease, with treatment success rates ranging from 55% to 65% 5.
• Standardized combination antibiotic therapy, consisting of clarithromycin, rifampicin, and ethambutol, with or without initial use of streptomycin, is also effective in treating patients with newly diagnosed MAC lung disease, with an overall favorable microbiologic response rate of 79% 6.

Factors Affecting Treatment Outcome

• A positive sputum acid-fast bacillus smear at the start of treatment is an independent predictor of an unfavorable microbiologic response 6.
• Prognostic factors for the progression of MAC pulmonary disease include low body mass index, poor nutritional status, presence of cavitary lesion(s), extensive disease, and a positive acid-fast bacilli smear 4.

New Therapies and Treatment Outcomes

• New therapies, including clofazimine, inhaled amikacin, and bedaquiline, have shown promising results for the treatment of MAC pulmonary disease, especially in patients with treatment failure or macrolide-resistant MAC pulmonary disease 4.
• Surgical lung resection can improve treatment outcomes in some refractory cases, but should be carefully performed in a well-equipped center and based on a rigorous risk-benefit analysis in a multidisciplinary setting 4.