What is the recommended antibiotic for treating bronchitis (inflammation of the bronchial tubes) with a suspected bacterial cause?

Antibiotic Treatment for Bronchitis

In most cases of acute bronchitis in otherwise healthy adults, antibiotics should NOT be prescribed, as acute bronchitis is typically viral and antibiotics provide no proven benefit. 1, 2

When Antibiotics Are NOT Indicated

• Acute bronchitis in healthy adults: The American College of Physicians and American Thoracic Society strongly recommend against antibiotic use, as clinical trials have not demonstrated benefit over placebo 2
• Simple chronic bronchitis exacerbation: Immediate antibiotic therapy is not recommended, even with fever present 1, 2
• Purulent sputum alone does NOT indicate bacterial infection and should not trigger antibiotic prescription 2

When Antibiotics ARE Indicated

Antibiotics should be prescribed only in specific clinical scenarios:

COPD Exacerbations with Bacterial Signs

• Prescribe antibiotics when at least 2 of 3 Anthonisen criteria are present: increased sputum purulence, increased dyspnea, and/or increased sputum volume 1
• Limit treatment duration to 5 days for COPD exacerbations with bacterial signs 1

Severe Chronic Obstructive Bronchitis

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

Persistent Fever

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

First-Line Antibiotic Selection

When antibiotics are indicated for suspected bacterial bronchitis:

Primary Recommendation

• Amoxicillin is the first-line agent for acute bacterial bronchitis 2
• Alternative: First-generation cephalosporins 2

For Penicillin Allergy

• Azithromycin (macrolide) is the preferred alternative 2, 3
• Other options: Doxycycline or pristinamycin 2

Dosing for Azithromycin

• 500 mg once daily for 3 days for acute exacerbations of chronic bronchitis 3
• FDA-approved for acute bacterial exacerbations of COPD due to H. influenzae, M. catarrhalis, or S. pneumoniae 3

Second-Line Options (Treatment Failure)

If first-line therapy fails after 2-3 days:

• Amoxicillin-clavulanate (reference second-line therapy) 1, 2
• Second-generation cephalosporins (cefuroxime-axetil) or third-generation (cefpodoxime-proxetil) 1, 2
• Respiratory fluoroquinolones (levofloxacin, moxifloxacin) for severe cases 2

Target Pathogens

Antibiotic selection should cover the most common bacterial causes:

• Streptococcus pneumoniae 2, 3
• Haemophilus influenzae 2, 3
• Moraxella catarrhalis 2, 3

Treatment Duration

• 5 days is sufficient for COPD exacerbations with bacterial signs 1
• 7-10 days for more severe chronic bronchitis exacerbations 1
• Extension beyond 5 days should be guided by clinical stability, not routine practice 1

Critical Clinical Pitfalls to Avoid

• Do not prescribe antibiotics for acute bronchitis in healthy adults - this is the most common error and contributes to antibiotic resistance 1, 2
• Do not assume purulent or colored sputum indicates bacterial infection - this is often viral 2
• Avoid fluoroquinolones as first-line therapy due to serious adverse effects, especially in elderly patients 4
• Do not use ciprofloxacin or ofloxacin - inadequate pneumococcal coverage 2
• Avoid cotrimoxazole - inconsistent pneumococcal activity and poor benefit/risk ratio 1, 2
• Distinguish bronchitis from pneumonia - pneumonia requires different management and chest radiography 2

Reassessment Strategy

• Evaluate clinical response after 2-3 days of antibiotic therapy 1
• If fever persists beyond 3 days or symptoms worsen, consider bacterial superinfection, pneumonia, or alternative diagnosis 1, 2
• Associated upper respiratory symptoms (rhinorrhea, nasal obstruction) suggest viral rather than bacterial etiology 1