What antibiotic is recommended for bronchitis of bacterial origin?

Antibiotic Treatment for Bacterial Bronchitis

For acute bronchitis in otherwise healthy adults, antibiotics should NOT be prescribed as this is primarily a viral illness with no proven benefit from antibiotic therapy. 1, 2

When Antibiotics Are NOT Indicated

• Acute bronchitis in healthy adults: Routine antibiotic treatment is not justified and should not be offered, as acute bronchitis is primarily viral in origin 1, 2
• Simple chronic bronchitis exacerbations: Immediate antibiotic therapy is not recommended, even if fever is present 1
• Purulent or discolored sputum (green/yellow) does NOT indicate bacterial infection and is not an indication for antibiotics 2

When Antibiotics ARE Indicated

Antibiotics should be prescribed in the following specific scenarios:

1. Chronic Obstructive Bronchitis with Anthonisen Criteria

• Prescribe antibiotics when at least 2 of 3 Anthonisen criteria are present: increased sputum volume, increased sputum purulence, and increased dyspnea 1, 2
• This applies to patients with FEV1 between 35% and 80% 2

2. Chronic Respiratory Insufficiency

• Immediate antibiotic therapy is recommended for patients with FEV1 <35% and hypoxemia at rest during exacerbations 1, 2

3. Persistent Fever

• Consider antibiotics if fever >38°C persists for more than 3 days, suggesting bacterial superinfection or pneumonia 1, 2

4. Confirmed Pertussis (Whooping Cough)

• A macrolide antibiotic is necessary for confirmed or suspected pertussis, with patient isolation for 5 days from treatment start 1

First-Line Antibiotic Recommendations

For bacterial bronchitis requiring treatment, amoxicillin is the preferred first-line agent. 2

• Amoxicillin: First-line choice for suspected bacterial bronchitis 2
• Azithromycin: Alternative first-line option, particularly effective with 500 mg once daily for 3 days 2, 3
  • Clinical cure rates of 85-88% in acute exacerbations of chronic bronchitis 3, 4
  • Well-tolerated with lower gastrointestinal side effects compared to some alternatives 4, 5
• Doxycycline or other macrolides: For patients with penicillin allergy 2

Second-Line Antibiotic Options

If first-line therapy fails, use amoxicillin-clavulanate as the reference second-line therapy. 2

• Amoxicillin-clavulanate: 625 mg three times daily for 7-10 days 1, 2
• Second or third-generation cephalosporins: Cefuroxime-axetil, cefpodoxime-proxetil (8 mg/kg/day in two doses), or cefotiam-hexetil 1, 2
• Respiratory fluoroquinolones: Levofloxacin or moxifloxacin (NOT ciprofloxacin or ofloxacin, which lack adequate pneumococcal coverage) 2, 6

Target Pathogens

Antibiotic selection must cover the three primary bacterial pathogens:

• Streptococcus pneumoniae 2
• Haemophilus influenzae 2
• Moraxella catarrhalis 2

Treatment Duration

• Azithromycin: 3-5 days (500 mg day 1, then 250 mg days 2-5, or 500 mg daily for 3 days) 2, 3
• Amoxicillin-clavulanate: 7-10 days 1, 2
• Clarithromycin: 7-10 days 7, 4

Critical Pitfalls to Avoid

• Do NOT prescribe antibiotics for acute bronchitis in healthy adults without clear bacterial indicators—this is the most common error 1, 2
• Do NOT assume purulent sputum indicates bacterial infection—sputum color alone is not diagnostic 2
• Do NOT use fluoroquinolones inactive against pneumococci (ciprofloxacin, ofloxacin) or cefixime 2
• Do NOT use cotrimoxazole due to inconsistent pneumococcal activity and poor benefit/risk ratio 1, 2
• Do NOT use aminopenicillins alone, first-generation cephalosporins, or macrolides as monotherapy in areas with high resistance rates 1
• Always distinguish bronchitis from pneumonia, which requires chest imaging and different management 2

Clinical Decision Algorithm

1. Assess patient category: Healthy adult vs. chronic obstructive bronchitis vs. chronic respiratory insufficiency
2. If healthy adult with acute bronchitis: Do NOT prescribe antibiotics 1, 2
3. If chronic bronchitis: Count Anthonisen criteria—need ≥2 of 3 to justify antibiotics 1, 2
4. If chronic respiratory insufficiency (FEV1 <35%): Start immediate antibiotic therapy 2
5. Check for fever persistence: If >38°C for >3 days, consider bacterial superinfection 1, 2
6. Associated ENT symptoms (rhinorrhea, nasal obstruction) suggest viral etiology—avoid antibiotics 1, 2