What is the recommended treatment for Streptococcus pneumoniae (strep pneumo) infections?

Treatment of Streptococcus pneumoniae Infections

For community-acquired pneumococcal pneumonia in adults without risk factors or severe illness, oral amoxicillin 3 g/day is the first-line treatment, while hospitalized patients should receive ampicillin or penicillin G intravenously (or third-generation cephalosporins like ceftriaxone/cefotaxime in areas with high-level penicillin resistance). 1

Outpatient Treatment (Adults)

First-Line Therapy

• Amoxicillin 3 g/day orally is the reference treatment for suspected pneumococcal pneumonia, particularly in adults over 40 years of age with or without underlying disease 1, 2
• Macrolides (azithromycin or clarithromycin) are alternatives for adults under 40 years with no underlying disease or when atypical bacteria are suspected 1
• Telithromycin or respiratory fluoroquinolones (levofloxacin, moxifloxacin) represent alternatives to these first-line options 1

Treatment Duration

• Continue therapy for 14 days for pneumococcal pneumonia 1
• Treatment should extend at least 48-72 hours beyond clinical improvement 1
• For non-severe cases, duration generally should not exceed 8 days in responding patients 1

Inpatient Treatment (Adults)

Non-Severe Hospitalized Patients

• Ampicillin (150-200 mg/kg/day IV) or penicillin G when local epidemiology shows lack of substantial high-level penicillin resistance 1
• Third-generation cephalosporins (ceftriaxone 50-100 mg/kg/day or cefotaxime 150 mg/kg/day) in regions with high-level penicillin resistance 1
• Combination therapy with a macrolide should be added if atypical pathogens (Mycoplasma, Chlamydophila) are considerations 1

Severe CAP (ICU Patients)

• Non-antipseudomonal third-generation cephalosporin (ceftriaxone or cefotaxime) PLUS macrolide 1
• Alternative: Moxifloxacin or levofloxacin (750 mg daily) ± third-generation cephalosporin 1
• If Pseudomonas risk factors present: antipseudomonal beta-lactam PLUS either ciprofloxacin OR macrolide plus aminoglycoside 1

Pediatric Treatment

Children Under 3 Years

• Amoxicillin 80-100 mg/kg/day in three divided doses for children weighing less than 30 kg 1
• This is the reference treatment as pneumococcus is the most frequent bacterial cause in this age group 1
• Treatment duration: 10 days for pneumococcal pneumonia 1

Children Over 3 Years

• Amoxicillin 90 mg/kg/day in 2 doses (or 45 mg/kg/day in 3 doses) if clinical picture suggests pneumococcal infection 1
• Macrolides if atypical bacteria (Mycoplasma, Chlamydophila) are suspected based on clinical/radiological findings 1

Hospitalized Children

• Ampicillin or penicillin G for fully immunized children in areas without high-level penicillin resistance 1
• Ceftriaxone (50-100 mg/kg/day) or cefotaxime (150 mg/kg/day) for incompletely immunized children, high-resistance areas, or life-threatening infections including empyema 1

Penicillin-Resistant Streptococcus pneumoniae

Intermediate Resistance (Penicillin MIC 0.1-2.0 µg/mL)

• Standard beta-lactam therapy remains effective because achievable serum/tissue concentrations exceed MICs 1, 3, 4
• Amoxicillin, ceftriaxone, or cefotaxime at standard doses are appropriate 1, 5
• High-dose amoxicillin (1 g every 8 hours in adults) or amoxicillin-clavulanate (875 mg twice daily) can be used 1

High-Level Resistance (Penicillin MIC ≥4.0 µg/mL)

• Respiratory fluoroquinolones (levofloxacin 750 mg daily, moxifloxacin) are preferred 1
• Alternative: Ceftriaxone 100 mg/kg/day (higher doses may overcome resistance) 1
• Vancomycin or linezolid reserved for treatment failures or documented high-level resistance 1
• Vancomycin has NOT been shown more effective than third-generation cephalosporins for current North American resistance patterns 1

Critical Pitfalls to Avoid

• Do not use amoxicillin-clavulanate routinely for pneumococcal pneumonia—no justification for adding beta-lactamase inhibitor against pneumococcus 1
• Avoid first-generation cephalosporins, trimethoprim-sulfamethoxazole, and tetracyclines due to inadequate activity against penicillin-resistant strains 1
• Do not change therapy within first 72 hours unless clinical deterioration occurs; symptoms should improve within 48-72 hours 1
• Assess therapeutic efficacy at 48-72 hours by monitoring fever resolution and clinical parameters 1
• Macrolide monotherapy may fail against erythromycin-resistant pneumococci; consider combination therapy or alternative agents 4
• Resistance to penicillin does NOT automatically mean clinical failure for non-meningeal infections when adequate dosing achieves sufficient tissue concentrations 3, 4, 5

Special Considerations

Meningitis

• Ceftriaxone or cefotaxime PLUS vancomycin until susceptibility known 1
• Penicillin has been largely abandoned for empiric meningitis treatment due to resistance concerns 6, 7

Sequential Therapy

• Switch from IV to oral therapy when clinical stability achieved (resolution of fever, stable vital signs) 1
• Same drug class can be continued orally (e.g., IV ceftriaxone to oral cefpodoxime, or IV to oral amoxicillin) 1
• Patients may be discharged after switching to oral therapy without prolonged observation 1