What are the guidelines for prescribing antibiotics for common bacterial infections?

Guidelines for Prescribing Antibiotics for Common Bacterial Infections

Antibiotics should only be prescribed when there is a clear indication of bacterial infection, using the most narrow-spectrum effective agent for the shortest appropriate duration to reduce antibiotic resistance and adverse effects. 1

General Principles of Antibiotic Prescribing

Diagnostic Approach

• Apply stringent diagnostic criteria to distinguish bacterial from viral infections 1
• Use biomarkers selectively:
  • Procalcitonin >0.5 ng/mL may indicate bacterial infection but should not be used alone for decision-making 1
  • C-reactive protein and white blood cell counts may help but are not definitive 1

Antibiotic Selection Framework: WHO AWaRe Classification

The WHO has developed a framework categorizing antibiotics into three groups 1:

1. Access antibiotics - First-line treatments for common infections; should be widely available
2. Watch antibiotics - Higher resistance potential; should be monitored and used more selectively
3. Reserve antibiotics - Last-resort options for multidrug-resistant infections; should be highly protected

Guidelines for Specific Common Infections

Upper Respiratory Tract Infections

Acute Otitis Media

• First-line: Amoxicillin for 5-7 days 1
• Second-line: Amoxicillin-clavulanate if treatment failure or high-risk factors 1
• Key point: Most cases in older children resolve spontaneously; consider watchful waiting in mild cases 1

Acute Bacterial Sinusitis

• First-line: Amoxicillin or amoxicillin-clavulanate for 5-7 days 1
• Second-line: Doxycycline or respiratory fluoroquinolone in penicillin-allergic patients 1
• Key point: Reserve antibiotics for patients with severe symptoms, high fever, or symptoms persisting >10 days 1

Streptococcal Pharyngitis

• First-line: Penicillin V or amoxicillin for 10 days 1
• Second-line: First-generation cephalosporin, clindamycin, or macrolide (if penicillin-allergic) 1
• Key point: Confirm diagnosis with rapid strep test or culture; do not treat viral pharyngitis 1

Lower Respiratory Tract Infections

Community-Acquired Pneumonia (CAP)

• Outpatient, healthy adults:
  • Amoxicillin or doxycycline for 5 days 1
• Outpatient with comorbidities:
  • Respiratory fluoroquinolone or combination therapy (β-lactam plus macrolide) for 5 days 1
• Hospitalized, non-ICU:
  • β-lactam plus macrolide or respiratory fluoroquinolone for 5-7 days 1
• Key point: Treatment can be safely limited to 5 days in patients who achieve clinical stability 1

Urinary Tract Infections

Uncomplicated Cystitis

• First-line:
  • Nitrofurantoin for 5 days
  • Trimethoprim-sulfamethoxazole for 3 days
  • Fosfomycin as single dose 1
• Key point: Avoid fluoroquinolones for uncomplicated cystitis due to risk of adverse effects 1

Uncomplicated Pyelonephritis

• First-line:
  • Fluoroquinolones for 5-7 days
  • Trimethoprim-sulfamethoxazole for 14 days (based on susceptibility) 1
• Key point: Local resistance patterns should guide empiric therapy 1

Skin and Soft Tissue Infections

Simple Abscesses

• First-line: Incision and drainage alone for simple abscesses 2
• Second-line: Add antibiotics for complicated cases (extensive, systemic symptoms) 2

Cellulitis

• First-line: β-lactam (e.g., cephalexin) for 5-10 days 2
• Second-line: Clindamycin, trimethoprim-sulfamethoxazole, or linezolid if MRSA suspected 2

Judicious Prescribing Practices

Antimicrobial Stewardship

1. Avoid antibiotics for viral infections - Most upper respiratory infections are viral and do not require antibiotics 1
2. Complete the prescribed course - Explain to patients that stopping early can lead to treatment failure and resistance 3
3. Use narrow-spectrum agents when possible - Target the likely pathogens rather than using broad-spectrum coverage 1
4. Consider shortest effective duration - Evidence supports shorter courses for many common infections 1
5. Monitor local resistance patterns - Adjust empiric therapy based on local epidemiology 1

Common Pitfalls to Avoid

• Prescribing antibiotics for viral infections (common cold, bronchitis) 1
• Using broad-spectrum agents when narrow-spectrum would suffice 1
• Extending treatment duration beyond necessary period 1
• Yielding to patient pressure for antibiotics when not indicated 1
• Failing to adjust therapy based on culture results 1

Patient Education

• Explain differences between viral and bacterial infections 3
• Discuss potential adverse effects of antibiotics (including C. difficile) 3
• Emphasize importance of completing the full course as prescribed 3
• Provide symptomatic management strategies for viral infections 1

Special Considerations

Immunocompromised Patients

• Lower threshold for empiric therapy but still aim for targeted treatment 1
• Consider broader initial coverage with prompt de-escalation when culture results available 1

COVID-19 Patients

• Antibiotics should be restricted in mild-to-moderate COVID-19 cases 1
• Consider antibiotics only for critically ill COVID-19 patients with suspected bacterial co-infection 1

By following these guidelines, clinicians can help ensure effective treatment of bacterial infections while minimizing unnecessary antibiotic use that contributes to resistance.