From the Guidelines
The optimal duration of antibiotic therapy should be individualized based on infection type, severity, and patient response, with a suggested duration of 7 to 10 days being adequate for most serious infections associated with sepsis and septic shock, as recommended by the Surviving Sepsis Campaign guidelines 1. The use of procalcitonin (PCT) and C-reactive protein (CRP) can guide antibiotic decisions, with PCT being more specific for bacterial infections.
- For PCT, levels <0.25 μg/L suggest antibiotics can be safely discontinued, while levels >0.5 μg/L indicate likely bacterial infection requiring continued treatment, as suggested by the American Thoracic Society and Infectious Diseases Society of America guidelines 1.
- Serial measurements showing declining values (>80% from peak) support antibiotic discontinuation.
- For CRP, values <10 mg/L suggest low bacterial infection likelihood, while >100 mg/L indicates active infection; a 50% reduction from peak values suggests adequate treatment response. These biomarkers should complement clinical judgment rather than replace it.
- PCT is particularly useful in respiratory and sepsis cases, while CRP may help monitor treatment response in conditions like pneumonia and sepsis, as noted in the European Respiratory Society guidelines 1. Implementation requires establishing institutional protocols with specific cutoff values, measurement frequency (typically every 24-48 hours), and clear stopping rules to effectively reduce unnecessary antibiotic use while maintaining patient safety, as emphasized by the Clinical Microbiology and Infection guidelines 1. In patients with COVID-19 and suspected bacterial co-infection, a treatment duration of five days is likely sufficient upon improvement of signs, symptoms, and inflammatory markers, as suggested by the Clinical Microbiology and Infection guidelines 1. Procalcitonin levels can be used to support shortening the duration of antibacterial therapy in patients with sepsis if the optimal duration of antibiotic therapy is unclear, as recommended by the Surviving Sepsis Campaign guidelines 1 and the Clinical Microbiology and Infection guidelines 1.
From the Research
Protocol for Antibiotic Duration
- The optimal duration of antibiotic treatment depends on various factors, including the type of infection, patient's condition, and microbiologic eradication 2.
- For community-acquired pneumonia, guidelines recommend antibiotic treatment for 7 to 21 days, but procalcitonin guidance can reduce total antibiotic exposure and treatment duration 3.
- In sepsis, procalcitonin and C-reactive protein can be used to guide antibiotic therapy, with a suggested duration of 7 days or less for many infections 4, 5.
Use of Procalcitonin or C-Reactive Protein
- Procalcitonin is elevated in bacterial infections and can be used to guide antibiotic therapy, with a threshold of 0.25 microg/L for discouraging antibiotic treatment 3.
- C-reactive protein can also be used to guide antibiotic therapy, with a meta-analysis showing that CRP-guided protocols reduce the duration of antibiotic therapy without increasing mortality or infection relapse rates 5.
- Both procalcitonin and C-reactive protein can be used to monitor the response to antibiotic therapy, with declining levels indicating a positive response 6.
Specific Guidelines
- For community-acquired pneumonia, procalcitonin guidance can reduce antibiotic use, with a median treatment duration of 5 days compared to 12 days with standard treatment 3.
- For sepsis, procalcitonin and C-reactive protein can be used to guide antibiotic therapy, with a suggested duration of 7 days or less for many infections 4, 2.
- For Gram-negative infections, the optimal duration of antibiotic therapy depends on various factors, including the severity of the infection and the patient's response to treatment 2.