What are the recommended antibiotic regimens for managing a brain abscess in adults?

Recommended antibiotic regimens for managing a brain abscess in adult patients:

• Initial empirical treatment typically involves high-dose intravenous antibiotics targeting the most common causative organisms, including aerobic and anaerobic bacteria.
• A common regimen includes intravenous amoxicillin combined with metronidazole and gentamicin to cover a broad spectrum of pathogens.
• Amoxicillin is given at 500 mg three times a day, increased to 1 g four times a day if the infection is severe.
• Gentamicin dosing is initially 5 to 7 mg/kg once daily, with subsequent doses adjusted based on serum levels and renal function monitoring.
• Metronidazole is administered at 500 mg three times a day to cover anaerobic bacteria.
• In patients allergic to penicillins or cephalosporins, ciprofloxacin (400 mg two or three times daily) combined with metronidazole (500 mg three times daily) may be used, but fluoroquinolones should be prescribed cautiously due to potential severe side effects.
• Duration of antibiotic therapy is often prolonged, typically several weeks, and should be guided by clinical response and imaging findings.
• Consultation with a microbiologist is recommended to tailor antibiotic choice and duration based on culture results and patient factors.

These recommendations align with UK guidelines on managing complicated infections with abscess formation and the use of broad-spectrum antibiotics covering likely pathogens in brain abscesses ¹.