How do I determine if a patient needs antibiotics?

Determining When a Patient Needs Antibiotics

Antibiotics should only be prescribed when there is a documented or strongly suspected bacterial infection, with regimens tailored to the specific infection site, severity, patient risk factors, and local resistance patterns. 1

Key Clinical Decision Points

1. Assess for Signs of Bacterial Infection

• Fever - Not all fevers require antibiotics; investigate the root cause first 2
• Laboratory markers - Elevated WBC count, left shift (>75%), elevated CRP, or procalcitonin >0.5 ng/mL may suggest bacterial infection 3
• Systemic signs - Assess vital signs using NEWS2 score to stratify risk 3

2. Evaluate by Clinical Syndrome

Respiratory Infections

• Viral respiratory infections including uncomplicated acute bronchitis should NOT receive antibiotics 1
• Community-acquired pneumonia requires antibiotics based on:
  • Clinical picture (fever, cough, respiratory distress)
  • Distinguishing between upper vs. lower respiratory tract involvement
  • Presence of underlying disease or risk factors 3

Skin and Soft Tissue Infections

• Uncomplicated superficial abscesses require drainage only, not antibiotics 3
• Surgical site infections with <5 cm of erythema/induration and minimal systemic signs (temperature <38.5°C, WBC <12,000/μL, pulse <100/min) do not need antibiotics 3
• Necrotizing infections require immediate surgical consultation and broad-spectrum antibiotics 3, 1

Intra-abdominal Infections

• Uncomplicated appendicitis/cholecystitis with adequate source control do not require post-operative antibiotics 3
• Complicated intra-abdominal infections with adequate source control require short-course therapy (3-5 days) 3
• Ongoing signs of infection beyond 7 days warrant diagnostic investigation 3

COVID-19 Associated Bacterial Infections

• Routine antibiotics are NOT recommended for COVID-19 patients 3
• Antibiotic prescription should be based on clinical justifications such as disease manifestations, severity, imaging, and laboratory data 3
• Comprehensive microbiologic workup should be done before empiric antibiotics 3

3. Risk Stratification for Antibiotic Decision-Making

High Risk (Start Antibiotics Promptly)

• Critically ill patients (NEWS2 score indicating high risk) 3
• Sepsis or septic shock 3
• Immunocompromised patients 3
• Severe infections with systemic manifestations 3

Moderate Risk (Consider Antibiotics)

• Moderate risk of severe illness based on NEWS2 score 3
• Specific clinical syndromes with evidence of bacterial etiology
• Persistent symptoms despite supportive care

Low Risk (Usually No Antibiotics Needed)

• Viral syndromes
• Uncomplicated infections with adequate source control 3
• Low risk of severe illness based on NEWS2 score 3

Timing of Antibiotic Administration

• High risk patients: Within 1 hour 3
• Moderate risk patients: Within 3 hours 3
• Low risk patients: Within 6 hours if antibiotics indicated 3

Common Pitfalls to Avoid

1. Treating fever without identifying the source: Fever alone is not an indication for antibiotics 2

2. Prescribing antibiotics for viral infections: Most upper respiratory infections are viral and do not benefit from antibiotics 1

3. Continuing empiric antibiotics when cultures are negative: De-escalate or discontinue antibiotics when infection is unlikely 1, 2

4. Not obtaining appropriate cultures before starting antibiotics: Always try to get microbiological samples before antibiotic administration 2

5. Failing to reassess: Antibiotic therapy should be regularly reassessed based on clinical response and culture results 2

By following these guidelines, you can make appropriate decisions about when to prescribe antibiotics, helping to improve patient outcomes while practicing good antimicrobial stewardship.