What is the recommended treatment for spontaneous bacterial peritonitis?

Treatment of Spontaneous Bacterial Peritonitis

Start third-generation cephalosporins immediately upon diagnosis—specifically intravenous cefotaxime 2g every 6-8 hours or ceftriaxone 1-2g every 12-24 hours for 5-10 days—and always add intravenous albumin (1.5 g/kg at diagnosis, then 1 g/kg on day 3) to prevent hepatorenal syndrome and reduce mortality. 1, 2, 3

Immediate Empirical Antibiotic Therapy

First-Line Treatment for Community-Acquired SBP

• Cefotaxime 2g IV every 6-8 hours achieves infection resolution rates of 69-98% and is the most extensively studied agent 1, 4, 5
• Ceftriaxone 1-2g IV every 12-24 hours is equally effective with resolution rates of 73-100% 1, 2, 3
• Treatment duration should be 5-10 days, with studies showing 5 days is as effective as 10 days 1, 4
• Lower doses are adequate: cefotaxime 2g every 12 hours (4g/day total) is as effective as 2g every 6 hours (8g/day total) 5

Alternative Antibiotic Options

• Amoxicillin-clavulanic acid (1g/0.2g IV every 8 hours, then switch to 0.5g/0.125g PO every 8 hours) achieves 87% resolution rates, comparable to cefotaxime 1, 3
• Oral ciprofloxacin 500mg every 12 hours can be used ONLY in clinically stable patients with uncomplicated community-acquired SBP who are not on quinolone prophylaxis 3, 6, 7
• Ofloxacin 400mg PO every 12 hours achieves 84% resolution in uncomplicated cases 3, 6

Critical Caveat on Quinolones

Do NOT use quinolones if: the patient is already taking them for prophylaxis, has nosocomial/hospital-acquired SBP, or is in an area with high quinolone resistance 1, 2

Hospital-Acquired or Nosocomial SBP

For patients with healthcare-associated SBP, recent hospitalization, ICU admission, or septic shock, use broader-spectrum coverage:

• Meropenem 1g IV every 8 hours plus daptomycin 6mg/kg/day in settings with high multidrug-resistant organism prevalence 2, 3
• Nosocomial SBP has a 35% multidrug-resistant organism rate and requires empirical carbapenem coverage 3
• In critically ill patients with CLIF-SOFA scores ≥7, empirical carbapenem treatment significantly reduces in-hospital mortality compared to third-generation cephalosporins (23.1% vs 38.8%) 8

Mandatory Adjunctive Albumin Therapy

Albumin is NOT optional—it dramatically improves outcomes:

• Administer IV albumin 1.5 g/kg at diagnosis, followed by 1.0 g/kg on day 3 1, 2, 3, 9
• This reduces hepatorenal syndrome type 1 from 30% to 10% 1, 3
• This reduces mortality from 29% to 10% 1, 3, 9
• Albumin is particularly critical in patients with baseline bilirubin ≥4 mg/dL or creatinine ≥1 mg/dL 1
• Crystalloids and artificial colloids (like hydroxyethyl starch) do NOT provide the same benefit 1

Monitoring Treatment Response

Repeat Paracentesis at 48 Hours

• Perform a second diagnostic paracentesis 48 hours after starting treatment to assess neutrophil count 1, 2, 3
• Treatment success is defined as ascitic neutrophil count decreasing to <250/mm³ and sterile cultures 1
• Expect at least a >25% reduction in neutrophil count from baseline 3

Suspect Treatment Failure If:

• Worsening clinical signs/symptoms 1
• No marked reduction or increase in ascitic neutrophil count 1, 3
• Ascitic PMN count increases to >1,000/mm³ 1
• Multiple organisms on Gram stain or culture (suggests secondary peritonitis) 1

When Treatment Fails:

• Change antibiotics according to culture susceptibility or broaden to alternative empiric agents 1, 3
• Rule out secondary bacterial peritonitis with abdominal CT imaging 1
• Consider resistant bacteria, particularly extended-spectrum beta-lactamase (ESBL)-producing organisms 2

Differentiating Secondary from Spontaneous Peritonitis

Suspect secondary bacterial peritonitis (which requires surgical intervention) if:

• Ascitic total protein ≥1 g/dL 1
• Ascitic LDH above normal serum upper limit 1
• Ascitic glucose ≤50 mg/dL 1
• Ascitic CEA >5 ng/mL or alkaline phosphatase >240 U/L 1
• PMN count does not drop after 48 hours of antibiotics 1
• Perform abdominal CT if secondary peritonitis is suspected 1

Long-Term Secondary Prophylaxis

After surviving an SBP episode, patients have a 70% one-year recurrence risk without prophylaxis:

• Start indefinite prophylaxis with norfloxacin 400mg daily until liver transplantation or death 2, 3, 9
• This reduces recurrence from 68% to 20% 2, 3, 9
• Ciprofloxacin 500mg daily is an acceptable alternative 2, 3
• Prophylaxis should continue indefinitely—there is no evidence-based endpoint except transplantation 2

Key Pitfalls to Avoid

• Never delay antibiotics waiting for culture results—start empirically immediately upon diagnosis (PMN >250/mm³) 1, 2, 3
• Never use aminoglycosides (like tobramycin) due to nephrotoxicity in cirrhotic patients 3, 4
• Never skip albumin administration—it is as important as antibiotics for reducing mortality 1, 3
• Never perform unnecessary laparotomy in cirrhotic patients without confirming secondary peritonitis, as it increases mortality 1
• Adjust treatment duration and antibiotic choice based on culture results and clinical response 1
• Consider local antibiotic resistance patterns when selecting empirical therapy 2, 3