What are the treatment and prophylaxis options for Spontaneous Bacterial Peritonitis (SBP)?

Treatment and Prophylaxis of Spontaneous Bacterial Peritonitis (SBP)

Acute Treatment of SBP

Start empirical antibiotics immediately upon diagnosis (ascitic fluid PMN ≥250 cells/mm³) without waiting for culture results—delaying treatment increases mortality by 10% for every hour's delay in septic shock. 1, 2

First-Line Antibiotic Therapy for Community-Acquired SBP

• Cefotaxime 2g IV every 8-12 hours for 5 days is the gold standard treatment, achieving infection resolution rates of 77-98% and covering the most common organisms (E. coli, Klebsiella, Streptococcus). 1, 2
• Ceftriaxone 1-2g IV every 12-24 hours is an equally effective alternative with resolution rates of 73-100%. 1, 3
• Five days of treatment is as effective as 10 days for carefully characterized SBP patients. 4, 2

Nosocomial or Healthcare-Associated SBP

For patients with recent hospitalization, ICU admission, septic shock, or in settings with high multidrug-resistant organism (MDRO) prevalence (now 35% in nosocomial SBP), use meropenem 1g IV every 8 hours plus daptomycin 6mg/kg/day as empirical therapy. 1

• Carbapenems are superior to third-generation cephalosporins specifically in critically ill patients with CLIF-SOFA scores ≥7, reducing mortality from 38.8% to 23.1%. 5

Alternative Antibiotic Options

• Amoxicillin/clavulanic acid 1g/0.2g IV every 8 hours achieves 87% resolution rates, comparable to cefotaxime. 1, 3
• Oral ofloxacin 400mg twice daily can be used ONLY in uncomplicated SBP (no vomiting, shock, grade II or higher encephalopathy, or creatinine ≥3 mg/dL), achieving 84% resolution. 4, 1
• Never use quinolones in patients already on quinolone prophylaxis, in areas with high quinolone resistance, or in nosocomial SBP. 2
• Avoid aminoglycosides (tobramycin) due to nephrotoxicity. 1

Essential Adjunctive Albumin Therapy

Administer IV albumin 1.5 g/kg body weight within 6 hours of diagnosis, followed by 1.0 g/kg on day 3—this reduces hepatorenal syndrome from 30% to 10% and mortality from 29% to 10%. 4, 1, 2

This dramatic survival benefit is one of the few interventions in advanced cirrhosis that significantly improves mortality, not just infection control. 4

Monitoring Treatment Response

• Perform repeat paracentesis at 48 hours to assess treatment efficacy. 1, 2
• Treatment success is defined as a decrease in ascitic PMN count to <25% of pre-treatment value with clinical improvement. 1, 2
• If PMN count fails to decrease by ≥25%, suspect treatment failure due to resistant bacteria or secondary bacterial peritonitis requiring broader antibiotics or surgical evaluation. 2, 3

Prophylaxis After SBP Episode

All patients surviving an SBP episode require indefinite long-term antibiotic prophylaxis until liver transplantation or death—without prophylaxis, recurrence risk is 68-70% within one year. 1, 3

Secondary Prophylaxis Regimen

• Norfloxacin 400mg PO daily is the most extensively studied regimen, reducing SBP recurrence from 68% to 20%. 1, 3
• Continue prophylaxis indefinitely until transplantation or resolution of ascites. 3
• Local resistance patterns should guide prophylaxis choice. 1

Primary Prophylaxis Indications

Patients with cirrhosis and ascites should receive primary prophylaxis in these specific situations:

• Low-protein ascites (total protein <1 g/dL) during hospitalization with norfloxacin 400mg daily. 6
• Upper gastrointestinal bleeding: norfloxacin 400mg twice daily for 7 days following the bleed. 6
• Severe ascites with advanced liver failure awaiting transplantation should be considered for long-term outpatient prophylaxis. 6

Critical Pitfalls to Avoid

• Never delay antibiotics waiting for culture results—the PMN count alone is sufficient to initiate therapy. 1, 2
• Do not use quinolones in patients already on quinolone prophylaxis—they will have resistant flora requiring cefotaxime or amoxicillin/clavulanic acid. 2
• Recognize the changing microbiology: widespread quinolone prophylaxis has shifted flora toward more gram-positives and quinolone-resistant organisms. 4
• Patients with alcoholic hepatitis can masquerade as SBP with fever, leukocytosis, and abdominal pain—but elevated ascitic PMN must still be presumed to represent SBP and treated empirically. 4
• Culture ascitic fluid at bedside in blood culture bottles (at least 10 mL) before starting antibiotics to increase culture sensitivity to >90%. 2
• Narrow antibiotic coverage once cultures are available and treat for the shortest effective duration for antibiotic stewardship. 1