What antibiotics are recommended for a patient with infected pulmonary tuberculosis (PTB) and bronchiectasis according to Infectious Diseases Society of America (IDSA) guidelines?

Antibiotic Recommendations for Infected Pulmonary Tuberculosis with Bronchiectasis

For patients with infected pulmonary tuberculosis (PTB) and bronchiectasis, the British Thoracic Society guidelines recommend targeted antibiotic therapy based on pathogen identification, with specific regimens for Pseudomonas aeruginosa and other common pathogens. 1

Antibiotic Selection Based on Pathogen

Pseudomonas aeruginosa Infection

• First-line treatment: Inhaled colistin for patients with chronic Pseudomonas aeruginosa infection who experience three or more exacerbations per year 1, 2
• Second-line alternative: Inhaled gentamicin if colistin is not tolerated 1, 2
• Alternative oral option: Azithromycin or erythromycin if patient cannot tolerate inhaled antibiotics 1
• Consider combination therapy: Adding azithromycin or erythromycin to inhaled antibiotics for patients with high exacerbation frequency 1

Non-Pseudomonas Infections

• First-line treatment: Azithromycin or erythromycin for patients with non-Pseudomonas infections 1
• Second-line alternative: Inhaled gentamicin 1
• Third-line option: Doxycycline for patients intolerant to macrolides or when macrolides are ineffective 1

Specific Antibiotic Regimens for Common Pathogens

Streptococcus pneumoniae

• First-line: Amoxicillin 500 mg three times daily for 14 days 1
• Alternative: Doxycycline 100 mg twice daily for 14 days 1

Haemophilus influenzae

• Beta-lactamase negative: Amoxicillin 500 mg three times daily for 14 days 1
• Beta-lactamase positive: Amoxicillin with clavulanic acid 625 mg three times daily for 14 days 1

Eradication Therapy for New Pathogens

New Pseudomonas aeruginosa Growth

• First-line eradication: Ciprofloxacin 500-750 mg twice daily for 2 weeks 1
• Second-line eradication: IV anti-pseudomonal beta-lactam ± IV aminoglycoside for 2 weeks, followed by 3 months of nebulized colistin, gentamicin, or tobramycin 1

New MRSA Growth

• Eradication therapy is recommended, especially due to infection control concerns 1

Treatment Approach Based on Exacerbation Frequency

Patients with ≥3 Exacerbations/Year

• Step 1: Optimize airway clearance with physiotherapy and consider mucoactive treatments 1
• Step 2: If Pseudomonas aeruginosa present, use long-term inhaled anti-pseudomonal antibiotic or long-term macrolide 1
• Step 3: If other potentially pathogenic microorganisms present, use long-term macrolides or targeted antibiotics 1
• Step 4: If no pathogen identified, use long-term macrolides 1

Important Safety Considerations

• Perform antimicrobial stewardship to prevent resistance development 1
• Before starting long-term macrolides: ensure no active NTM infection with at least one negative respiratory NTM culture 1
• Use aminoglycosides with caution in patients with significant hearing loss or balance issues 1
• Avoid inhaled aminoglycosides if creatinine clearance <30ml/min 1
• Avoid concomitant nephrotoxic medications with inhaled aminoglycosides 1
• Monitor patients on long-term antibiotics every 6 months to assess efficacy, toxicity, and continuing need 1, 2
• Regularly monitor sputum culture and sensitivity, although in vitro resistance may not affect clinical efficacy 1

Special Considerations for PTB with Bronchiectasis

• The current use of LAMAs/SAMAs (long-acting/short-acting muscarinic antagonists) is relatively safe regarding PTB or pneumonia risks 3
• Use LABAs/SABAs (long-acting/short-acting beta-agonists) and steroids cautiously as they may increase risk of PTB or pneumonia in patients with bronchiectasis-asthma combinations 3

Remember that antibiotic selection should be guided by sputum culture and sensitivity results whenever possible, and treatment should be adjusted based on clinical response 1.