What is the treatment for infections caused by Mycobacterium (mycobacterium) and Mycoplasma (mycoplasma)?

Treatment of Mycobacterium and Mycoplasma Infections

For Mycobacterium infections, treat with rifampicin and ethambutol for 24 months as the foundational regimen, while Mycoplasma pneumoniae respiratory infections require macrolides (azithromycin or clarithromycin) or doxycycline as first-line therapy.

Mycoplasma Infections

Mycoplasma pneumoniae (Respiratory Tract Infections)

• Doxycycline is FDA-approved for respiratory tract infections caused by Mycoplasma pneumoniae 1
• Azithromycin is FDA-approved for community-acquired pneumonia due to Mycoplasma pneumoniae in patients appropriate for oral therapy 2
• Standard dosing: Doxycycline 100 mg twice daily or azithromycin 500 mg once daily 1, 2

Important caveat: Azithromycin should not be used in patients with pneumonia who have moderate to severe illness, cystic fibrosis, nosocomial infections, bacteremia, require hospitalization, are elderly/debilitated, or have immunodeficiency 2

QT Prolongation Risk with Macrolides

• Azithromycin carries risk of QT prolongation and torsades de pointes, which can be fatal 2
• Avoid in patients with: known QT prolongation, history of torsades de pointes, congenital long QT syndrome, bradyarrhythmias, uncompensated heart failure, or those on Class IA/III antiarrhythmics 2
• Elderly patients are more susceptible to QT interval effects 2

Mycobacterium Infections

Non-Tuberculous Mycobacteria (NTM)

M. avium Complex (MAC) - Pulmonary Disease

• First-line treatment: rifampicin (450 mg if <50 kg, 600 mg if >50 kg) plus ethambutol (15 mg/kg) for 24 months 3
• Isoniazid may be added but offers no proven additional benefit 3
• Treatment success rate approximately 72% (28% failure/relapse rate) 3
• For treatment failures: add ciprofloxacin (750 mg twice daily), clarithromycin (500 mg twice daily), or streptomycin (0.75-1 g IM daily) until culture negative for 12 months 3
• Surgery (resection) is an option for unilateral disease in fit patients who fail medical therapy 3

MAC - Extrapulmonary Disease (Lymph Nodes in Children)

• Complete surgical excision is the treatment of choice 3
• Avoid aspiration, incision, or drainage due to risk of discharging sinus and scarring 3
• Chemotherapy with rifampicin, ethambutol, and clarithromycin for up to 2 years only if: disease recurs, excision incomplete/impossible, or to debulk before excision 3
• For non-lymph node sites: chemotherapy for 18-24 months 3

M. malmoense - Pulmonary Disease

• Treatment: rifampicin and ethambutol for 24 months 3
• This regimen offers best balance between cure and adverse effects 3
• 10% remain culture-positive or relapse after 2 years of treatment 3
• Surgery for unilateral disease in patients not responding to chemotherapy who are fit enough 3
• Continue chemotherapy for at least 18 months post-surgery 3

M. xenopi - Pulmonary Disease

• Treatment: ethambutol and rifampicin for 2 years 3
• Surgery for treatment failures in surgical candidates 3
• Critical warning: 55% five-year mortality rate, with 7% directly attributable to M. xenopi infection 3
• Adding ethionamide and cycloserine increases toxicity and poor compliance without improving outcomes 3

Rapidly Growing Mycobacteria (M. chelonae, M. fortuitum, M. abscessus)

Pulmonary disease:

• Surgery should be employed if possible 3
• Regimen: rifampicin (450 mg if <50 kg, 600 mg if >50 kg), ethambutol (15 mg/kg), and clarithromycin (500 mg twice daily) taken together each morning 3
• Quinolones, sulphonamides, amikacin, cefoxitin, and imipenem may have adjunctive roles 3
• Cure may not be attainable 3

Wound infections (M. fortuitum or M. chelonae):

• Surgical debridement followed by ciprofloxacin (750 mg twice daily) plus aminoglycoside or imipenem 3
• Some clinicians add clarithromycin (500 mg twice daily) 3

M. marinum skin infections:

• May heal spontaneously 3
• Treatment options: cotrimoxazole, tetracycline, or rifampicin plus ethambutol in standard doses 3

Duration of therapy: If response to initial 6 months is suboptimal, prolong chemotherapy up to 2 years 3

Tuberculosis (M. tuberculosis)

Drug-Susceptible TB

• Standard regimen: isoniazid, rifampicin, pyrazinamide, and ethambutol 4, 5, 6
• Ethambutol should not be used as sole antituberculous drug but combined with at least one other agent 4
• Treatment duration typically 6 months for pulmonary TB 7, 5

Isoniazid-Resistant TB

• Treat with isoniazid, rifampin, pyrazinamide, and ethambutol daily for 6 months 7
• This regimen produced successful outcomes with no treatment failures in clinical practice 7
• 95% of patients with pulmonary involvement converted sputum cultures to negative within 2 months 7

Multidrug-Resistant TB (MDR-TB)

• Combine residual first-line drugs (ethambutol, pyrazinamide, streptomycin) with second-line drugs based on susceptibility patterns 8
• Fluoroquinolones represent the most significant therapeutic advance for MDR-TB 8
• If local drug resistance >4% or unknown, add fourth drug (ethambutol or streptomycin) 6
• Treatment requires considerable expertise and should follow hierarchy based on intrinsic activity and clinical efficacy 8

TB Meningitis

• Minimum 12 months therapy recommended by ATS/CDC 6
• Initial regimen: isoniazid, pyrazinamide, rifampin, plus ethambutol or streptomycin 6
• Corticosteroids recommended for Stage II (confused/neurologic signs) and Stage III (comatose) patients 6
• Dexamethasone 6-12 mg/day or prednisone 60-80 mg/day tapered over 4-8 weeks 6
• Extend therapy to 18 months if cultures remain positive or slow response 6

HIV-Positive Patients with Mycobacterial Infections

MAC in HIV/AIDS

• Treatment: rifampicin (or rifabutin 300 mg daily), ethambutol (15 mg/kg daily), and clarithromycin (500 mg twice daily) or azithromycin (500 mg daily) 3
• Continue lifelong therapy as discontinuation results in recurrence 3
• For treatment failures: add ciprofloxacin (750 mg twice daily) or amikacin (15 mg/kg daily in two divided doses) 3
• Drug interaction warning: Rifamycins decrease protease inhibitor levels; consider rifabutin substitution or protease inhibitor-free regimens 3

M. kansasii Disseminated Disease in HIV

• Treatment: rifampicin, ethambutol, and clarithromycin, possibly with isoniazid, for as long as patient lives 3