What is the appropriate use and selection of antibiotics for treating bacterial infections?

Appropriate Use and Selection of Antibiotics for Bacterial Infections

Antibiotics should be prescribed only for confirmed or highly suspected bacterial infections, using the narrowest spectrum agent effective against the likely pathogen, for the shortest duration needed to resolve the infection, while considering local resistance patterns. The appropriate selection and use of antibiotics is critical to maximize clinical outcomes while minimizing antimicrobial resistance development.

Antibiotic Selection Framework: The AWaRe Classification

The World Health Organization (WHO) has developed the AWaRe (Access, Watch, Reserve) classification system to guide appropriate antibiotic use 1:

Access Group

• First-line antibiotics for common infections
• Should be widely available, affordable, and of assured quality
• Examples: amoxicillin, trimethoprim-sulfamethoxazole, nitrofurantoin

Watch Group

• Higher resistance potential and toxicity concerns
• Should be targeted for stewardship programs
• Examples: fluoroquinolones, macrolides, carbapenems

Reserve Group

• Last-resort options for multidrug-resistant infections
• Should be protected and used only when other options fail
• Examples: colistin, linezolid, some newer antibiotics

Infection-Specific Antibiotic Recommendations

Urinary Tract Infections (UTIs)

Uncomplicated Cystitis in Women

• First choice: Short-course therapy with:
  • Nitrofurantoin for 5 days
  • Trimethoprim-sulfamethoxazole (TMP-SMX) for 3 days
  • Fosfomycin as a single dose 1

Uncomplicated Pyelonephritis

• First choice: Short-course therapy with:
  • Fluoroquinolones for 5-7 days (if susceptible)
  • TMP-SMX for 14 days (based on susceptibility testing) 1

Important caveat: Fluoroquinolones should not be used empirically for uncomplicated cystitis due to adverse effects and should be reserved for patients with resistant organisms or pyelonephritis 1.

Respiratory Tract Infections

Acute Rhinosinusitis

Reserve antibiotics for patients with:

• Persistent symptoms >10 days without improvement
• Severe symptoms (fever >39°C, purulent nasal discharge, facial pain) for ≥3 consecutive days
• Worsening symptoms after initial improvement ("double sickening") 1

First choice: Amoxicillin-clavulanate (alternatives: doxycycline or respiratory fluoroquinolone) 1

Common Cold/Viral Upper Respiratory Infections

• No antibiotics indicated - these are viral infections 1
• Antibiotics do not prevent complications such as sinusitis, otitis media, or asthma exacerbation 1

Key Principles for Appropriate Antibiotic Use

1. Confirm bacterial infection: Distinguish between bacterial and viral etiologies before prescribing antibiotics

2. Use short-course therapy: Recent evidence supports shorter antibiotic courses for many common infections 1

3. Consider local resistance patterns: Empiric therapy should be guided by local antimicrobial susceptibility data

4. De-escalate when possible: Narrow therapy based on culture results

5. Avoid fluoroquinolones for uncomplicated infections: Due to adverse effects and resistance concerns 1

Common Pitfalls in Antibiotic Prescribing

1. Treating viral infections with antibiotics: Antibiotics are ineffective against viral infections and may lead to adverse effects and resistance 2

2. Subinhibitory antibiotic concentrations: Can actually increase bacterial virulence and worsen infections, particularly with β-lactams and tetracyclines 3

3. Empiric broad-spectrum therapy without de-escalation: Contributes to resistance development

4. Inappropriate antibiotic use during viral pandemics: During COVID-19, up to 75% of patients received antibiotics despite bacterial co-infection rates of only 3.5% 4

5. Prolonged treatment durations: Longer courses rarely provide additional benefit but increase risk of adverse effects and resistance

Special Considerations

Antibiotic Formulations

• Consider patient factors when selecting between oral tablets, capsules, or suspensions 5, 6
• For children and those unable to swallow tablets, suspensions are available in various concentrations 5

Patient Education

• Explain that antibiotics treat bacterial infections only, not viral infections like the common cold 6
• Emphasize the importance of completing the full course as prescribed 6
• Advise patients to contact their healthcare provider if they develop diarrhea during or after antibiotic treatment 6

By following these evidence-based recommendations and principles, clinicians can optimize antibiotic use to effectively treat bacterial infections while minimizing the development of antimicrobial resistance.