What are the recommended antibiotics for treating pneumococcal infections?

Recommended Antibiotics for Pneumococcal Infections

For pneumococcal infections, beta-lactam antibiotics remain the first-line treatment, with penicillin or amoxicillin as the preferred agents for susceptible strains, while fluoroquinolones or combination therapy should be reserved for severe infections or resistant strains. 1

First-Line Treatment Options by Setting

Outpatient Treatment

• Mild to moderate pneumococcal pneumonia:
  • First choice: Amoxicillin 90 mg/kg/day in 2 doses (maximum 4 g/day) 2
  • Alternative: Amoxicillin-clavulanate 2
  • For penicillin-allergic patients: Doxycycline or a respiratory fluoroquinolone (levofloxacin, moxifloxacin) 1

Hospitalized Patients (Non-ICU)

• Recommended regimen:
  • Beta-lactam (cefotaxime, ceftriaxone, or ampicillin-sulbactam) plus a macrolide 1
  • Alternative: Respiratory fluoroquinolone monotherapy (levofloxacin 750 mg daily or moxifloxacin) 3

Severe Pneumonia (ICU)

• Recommended regimen:
  • Beta-lactam (cefotaxime, ceftriaxone, or ampicillin-sulbactam) plus either:
    • A macrolide (clarithromycin or azithromycin) OR
    • A respiratory fluoroquinolone 1

Treatment Based on Penicillin Susceptibility

Penicillin-Susceptible Strains (MIC ≤2 mg/L)

• First choice: Penicillin G or amoxicillin 1, 4
• Dosing for severe infections:
  • Penicillin G: 3 million unit loading dose followed by 10-12 million units every 12 hours as continuous infusion 5
  • Amoxicillin: 1g every 8 hours 1

Intermediate Resistance (MIC 2-4 mg/L)

• Recommended: Higher doses of beta-lactams 6
  • Cefotaxime 2g IV q8h or
  • Ceftriaxone 2g IV q24h or
  • High-dose amoxicillin (1g every 8h) 1

High-Level Resistance (MIC ≥4 mg/L)

• Recommended options:
  • Respiratory fluoroquinolones (levofloxacin, moxifloxacin) 6
  • Vancomycin 1
  • Linezolid (for MRSA) 1

Duration of Therapy

• Uncomplicated pneumococcal pneumonia: 5-7 days 1
• Bacteremic pneumococcal pneumonia: 10-14 days 1
• Severe pneumonia: 10 days, extended to 14-21 days for complicated cases 1

Special Considerations

Risk of Drug-Resistant Strains

• In areas with high prevalence of drug-resistant pneumococci (DRSP), consider:
  • Higher doses of beta-lactams
  • Combination therapy with a beta-lactam plus a macrolide
  • Respiratory fluoroquinolones 1, 6

Bacteremic Pneumococcal Pneumonia

• Recommended: Combination therapy shows lower mortality (8.2% vs 23.1%) in critically ill patients 1
• Duration: Minimum 10-14 days with monitoring for metastatic complications 1

Pediatric Considerations

• First-line for children <5 years: Amoxicillin 90 mg/kg/day in 2 doses 2
• Severe pneumonia requiring hospitalization: Ampicillin (150-200 mg/kg/day divided every 6 hours) 2

Pitfalls to Avoid

1. Macrolide monotherapy in areas with high resistance: Avoid empiric macrolide monotherapy in areas with high prevalence of macrolide-resistant pneumococci 6

2. Delayed treatment: Initiate antibiotics immediately after diagnosis, as delayed treatment increases mortality 1

3. Prolonged IV therapy: Switch from IV to oral therapy as soon as clinical improvement occurs and temperature has been normal for 24 hours 1

4. Fluoroquinolone overuse: Reserve fluoroquinolones for patients with risk factors for resistant organisms or treatment failures to prevent development of resistance 1, 6

5. Inadequate dosing: Ensure appropriate dosing based on the suspected level of resistance, particularly for beta-lactams 5, 7

The emergence of drug-resistant pneumococci has complicated treatment, but with appropriate antibiotic selection and dosing based on local resistance patterns, most pneumococcal infections can be effectively treated while preserving the utility of our antimicrobial armamentarium.