From the Guidelines
Bacterial bronchitis is most commonly caused by Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, as indicated by the most recent and highest quality study 1. These bacteria typically infect the bronchial tubes after a viral respiratory infection has already damaged the protective lining of the airways, creating an opportunity for bacterial invasion. Other causes include Mycoplasma pneumoniae, Chlamydia pneumoniae, and Bordetella pertussis. Risk factors that increase susceptibility include:
- Smoking
- Exposure to air pollutants
- Weakened immune systems
- Chronic conditions like COPD or cystic fibrosis Bacterial bronchitis often develops as a secondary infection following a viral illness, when symptoms worsen after initial improvement or persist beyond 10-14 days. The bacterial infection triggers inflammation in the bronchial tubes, leading to increased mucus production, which causes the characteristic productive cough with yellow or green sputum. Treatment typically involves antibiotics such as amoxicillin (500mg three times daily for 5-7 days), amoxicillin-clavulanate (875/125mg twice daily for 5-7 days), or doxycycline (100mg twice daily for 5-7 days), depending on suspected pathogens and local resistance patterns, as recommended by 1 and supported by older studies like 1 and 1. However, it's essential to note that not all cases of bronchitis are bacterial in nature, and the use of antibiotics should be guided by clinical judgment and evidence of bacterial infection, as emphasized by 1. In cases where bacterial infection is suspected, the choice of antibiotic should be based on effective treatment of the most commonly reported bacterial pathogens, as stated in 1. It's also crucial to consider the potential for antibiotic resistance and to use antibiotics judiciously, as highlighted by 1. Overall, the management of bacterial bronchitis requires a thoughtful and evidence-based approach, taking into account the most recent and highest quality research, such as 1.
From the FDA Drug Label
- 5 Acute Bacterial Exacerbation of Chronic Bronchitis Levofloxacin tablets are indicated for the treatment of acute bacterial exacerbation of chronic bronchitis due to methicillin-susceptible Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, Haemophilus parainfluenzae, or Moraxella catarrhalis. (2) Lower respiratory tract infections, including pneumonia, caused by Streptococcus pneumoniae (formerly Diplococcus pneumoniae), Streptococcus pyogenes* (Group A streptococci) and other streptococci (excluding enterococci, e.g., Enterococcus faecalis), Staphylococcus aureus (penicillinase and non-penicillinase producing), Escherichia coli, Klebsiella species, Haemophilus influenzae (including ampicillin resistant strains), Haemophilus parainfluenzae, Proteus mirabilis, Serratia marcescens*, Enterobacter species, indole positive Proteus and Pseudomonas species (including P. aeruginosa).
The common causes of bacterial bronchitis include:
- Methicillin-susceptible Staphylococcus aureus
- Streptococcus pneumoniae
- Haemophilus influenzae
- Haemophilus parainfluenzae
- Moraxella catarrhalis
- Escherichia coli
- Klebsiella species
- Proteus mirabilis
- Serratia marcescens
- Enterobacter species
- Pseudomonas species 2 3
From the Research
Common Causes of Bacterial Bronchitis
The common causes of bacterial bronchitis include:
- Haemophilus influenzae 4, 5, 6, 7
- Moraxella catarrhalis 4, 5, 6, 7
- Streptococcus pneumoniae 4, 5, 8, 6, 7
- Pseudomonas aeruginosa 4, 8
- Staphylococcus aureus 6
- Chlamydia pneumoniae 5
- Branhamella catarrhalis 8
Risk Factors for Bacterial Bronchitis
Risk factors for bacterial bronchitis include:
- Chronic obstructive pulmonary disease (COPD) 4
- Co-morbid illness 4
- Severe obstruction (FEV1 < 50%) 4
- Old age (> 65 years) 4
- Recurrent exacerbations 4
- Immunocompromised patients 5
Diagnosis and Treatment
Diagnosis of bacterial bronchitis is often based on clinical impression, although suspicion of bacterial infection can be enhanced by quantitative Gram's stains from appropriately obtained sputum specimens 4. Treatment involves non-drug interventions (e.g. smoking cessation) and antibiotic treatment 4. The selection of an antibiotic for treatment of an infectious episode must consider underlying patient co-morbidities, likely pathogens, resistance issues, and individual antibiotic properties 4.