From the Guidelines
Moraxella catarrhalis infections should be treated with amoxicillin with clavulanic acid 625 mg three times a day for 14 days as the first-line antibiotic therapy. This recommendation is based on the British Thoracic Society guideline for bronchiectasis in adults, which suggests this treatment regimen for Moraxella catarrhalis infections 1.
Key Considerations
- The guideline also recommends alternative treatment options, including clarithromycin 500 mg twice daily, doxycycline 100 mg twice daily, and ciprofloxacin 500 mg or 750 mg twice daily, in case of resistance or allergy to amoxicillin with clavulanic acid 1.
- It is essential to note that over 90% of M. catarrhalis strains produce beta-lactamase, making them resistant to plain amoxicillin and penicillin.
- Treatment should be started promptly, especially in patients with underlying respiratory conditions like COPD where M. catarrhalis infections can cause exacerbations.
- Symptoms typically improve within 48-72 hours of starting appropriate antibiotics, and if symptoms persist beyond this timeframe, reevaluation may be necessary to confirm the diagnosis or consider alternative pathogens.
Treatment Options
- First-line treatment: amoxicillin with clavulanic acid 625 mg three times a day for 14 days
- Alternative treatments:
- Clarithromycin 500 mg twice daily for 14 days
- Doxycycline 100 mg twice daily for 14 days
- Ciprofloxacin 500 mg or 750 mg twice daily for 14 days It is crucial to choose the most appropriate antibiotic based on the patient's specific condition, allergy status, and potential resistance patterns, as highlighted in the British Thoracic Society guideline 1.
From the FDA Drug Label
1.1 Acute Bacterial Exacerbation of Chronic Bronchitis Clarithromycin extended-release tablets are indicated in adults for the treatment of mild to moderate infections caused by susceptible isolates due to Haemophilus influenzae, Haemophilus parainfluenzae, Moraxella catarrhalis,or Streptococcus pneumoniae 1.1 Lower Respiratory Tract Infections – caused by beta-lactamase–producing isolates of Haemophilus influenzae and Moraxella catarrhalis. The treatment options for Moraxella catarrhalis infections with antibiotics are:
- Clarithromycin: for mild to moderate infections in adults, with a recommended dosage of 1 gram every 24 hours for 7-14 days, depending on the infection type 2
- Amoxicillin-clavulanate: for infections caused by beta-lactamase–producing isolates of Moraxella catarrhalis, in conditions such as lower respiratory tract infections, acute bacterial otitis media, and sinusitis 3
From the Research
Treatment Options for Moraxella catarrhalis Infections with Antibiotics
- The choice of antibiotic for treating Moraxella catarrhalis infections should be based on sensitivity reports to ensure rapid response and recovery of patients 4.
- Moraxella catarrhalis isolates have shown high resistance to ampicillin, penicillin, and cotrimoxazole, but are generally susceptible to cefotaxime, ciprofloxacin, erythromycin, and amoxicillin/clavulanic acid 4, 5, 6, 7.
- Cefuroxime, cefotaxime, and ceftazidime have been used to treat Moraxella catarrhalis bacteremia, often followed by oral amoxicillin/clavulanate or cefuroxime axetil 8.
- Amoxicillin/clavulanic acid and cephalosporins appear to be reliable first-line therapies for Moraxella catarrhalis infections, especially in cases where beta-lactamase production is suspected 5, 6.
- Other antibiotics that have shown effectiveness against Moraxella catarrhalis include chloramphenicol, doxycycline, tetracycline, fusidic acid, clarithromycin, and rifampin 7.
Antibiotic Resistance Patterns
- Moraxella catarrhalis isolates have been found to produce beta-lactamase, which confers resistance to ampicillin and other beta-lactam antibiotics 4, 5, 6, 7.
- Resistance to trimethoprim, sulfamethoxazole, and tetracycline has also been reported in some Moraxella catarrhalis isolates 6, 7.
- The use of antibiotic sensitivity testing is crucial in guiding the selection of effective antibiotics for treating Moraxella catarrhalis infections 4, 7.