What is the recommended treatment for spontaneous bacterial peritonitis (SBP)?

Treatment of Spontaneous Bacterial Peritonitis

Third-generation cephalosporins are the recommended first-line treatment for spontaneous bacterial peritonitis (SBP), with cefotaxime 2g IV every 6-8 hours or ceftriaxone 1g every 12-24 hours for 5-7 days, along with IV albumin (1.5 g/kg on day 1 and 1 g/kg on day 3) to reduce mortality and prevent hepatorenal syndrome. 1

Diagnosis

Before initiating treatment, proper diagnosis is essential:

• Diagnostic paracentesis is mandatory in all patients with:

  • New-onset ascites
  • Cirrhotic patients with ascites on hospital admission
  • Patients with GI bleeding, shock, fever, signs of systemic inflammation
  • Worsening liver/renal function or hepatic encephalopathy 1

• SBP is diagnosed when:

  • Ascitic fluid polymorphonuclear leukocyte (PMN) count is >250/mm³, regardless of culture results 2, 1
  • Blood cultures should be performed before starting antibiotics 2

Antibiotic Treatment

First-line therapy (Community-acquired SBP):

• Third-generation cephalosporins:
  • Cefotaxime 2g IV every 6-8 hours for 5-7 days 2, 1
  • Ceftriaxone 1g IV every 12-24 hours for 5-7 days 1
  • Five-day therapy is as effective as 10-day treatment 2

Alternative regimens:

• Amoxicillin-clavulanic acid: Similar efficacy to cefotaxime but with potential concerns for drug-induced liver injury 2, 1
• Ciprofloxacin: Can be used in uncomplicated cases without renal failure, hepatic encephalopathy, GI bleeding, ileus, or shock 2, 1
  • Oral ofloxacin has shown similar results to IV cefotaxime in uncomplicated SBP 2

Hospital-acquired (nosocomial) SBP:

• Consider broader-spectrum antibiotics due to potential resistance patterns 1
• Recent evidence suggests meropenem plus daptomycin is more effective than ceftazidime (86.7% vs 25% resolution) for nosocomial SBP 3

Adjunctive Therapy

Albumin administration:

• IV albumin should be administered in addition to antibiotics:
  • 1.5 g/kg on day 1 and 1 g/kg on day 3 1
  • Particularly beneficial for patients with:
    • Acute kidney injury
    • Jaundice
    • Serum creatinine ≥1 mg/dL
  • Reduces hepatorenal syndrome incidence and decreases mortality from 29% to 10% 1

Monitoring Treatment Response

• Follow-up paracentesis after 48 hours of antibiotic therapy is recommended 1
• Treatment failure should be suspected if:
  • No clinical improvement after 48 hours
  • Reduction in ascitic fluid neutrophil count <25% of pretreatment value 3

Special Considerations

Secondary bacterial peritonitis:

• Suspect when:
  • Multiple organisms on ascitic culture
  • Very high ascitic neutrophil count (>1000/mm³)
  • High ascitic protein concentration
  • Inadequate response to therapy 2, 1
• Management:
  • Prompt CT scanning
  • Early consideration for surgery
  • Anaerobic antibiotic coverage 2, 1

Bacterascites:

• Defined as neutrophil count <250/mm³ but positive bacterial culture
• Treat if signs of systemic inflammation or infection are present
• Otherwise, perform a second paracentesis; if culture remains positive, treat regardless of neutrophil count 2

Prophylaxis After SBP Episode

• Patients who have recovered from SBP should receive:
  • Norfloxacin 400 mg daily
  • Ciprofloxacin
  • Co-trimoxazole 1
• Continue prophylaxis until definitive resolution of ascites or liver transplantation 4

Pitfalls and Caveats

1. Avoid nephrotoxic antibiotics (e.g., aminoglycosides) as empirical therapy in SBP patients, as they may accelerate loss of residual renal function 2, 1

2. Consider antibiotic resistance: The spread of multi-drug resistant organisms has led to an increase in infections resistant to traditional therapies, particularly in hospital-acquired cases 2, 3

3. Non-selective beta-blockers (NSBBs) should be temporarily held in patients who develop hypotension or acute kidney injury 1

4. Don't delay treatment: Antibiotics should be started immediately after diagnosis of SBP, before culture results are available 2, 1

5. Consider IV albumin: Failure to administer albumin in appropriate patients significantly increases mortality risk 1