What is the recommended prophylaxis for suspected Spontaneous Bacterial Peritonitis (SBP) in patients with ascites and cirrhosis?

Prophylaxis for Suspected SBP in Cirrhosis with Ascites

Direct Recommendation

For patients with suspected SBP in the setting of cirrhosis and ascites, immediately initiate empirical antibiotic treatment with cefotaxime 2g IV every 8 hours (or ceftriaxone 2g IV daily) for 5 days, and administer albumin 1.5 g/kg within 6 hours followed by 1 g/kg on day 3 if there are any signs of renal impairment. 1, 2

Treatment of Suspected/Active SBP

Immediate Antibiotic Therapy

• Cefotaxime 2g IV every 8-12 hours is the first-line treatment for suspected SBP, covering 95% of typical organisms (E. coli, Streptococcus species, and enterococci that account for 70% of cases) 1, 3
• Five days of treatment is as effective as 10 days, and lower doses (2g twice daily) are similar in efficacy to higher doses (2g four times daily) 1
• Alternative third-generation cephalosporins include ceftriaxone and ceftazidime, or co-amoxiclav 1

Critical Albumin Administration

• Albumin infusion (1.5 g/kg within first 6 hours, then 1 g/kg on day 3) must be given to patients with any signs of developing renal impairment or sepsis, as this significantly reduces mortality in cirrhotic patients with severe infections 1, 4
• This intervention is crucial even in suspected cases, as it prevents hepatorenal syndrome development 3

Diagnostic Confirmation

• Perform diagnostic paracentesis immediately and inoculate ascitic fluid into blood culture bottles at bedside 1
• Obtain blood and urine cultures before initiating antibiotics to guide subsequent therapy 4
• SBP is confirmed when ascitic fluid neutrophil count is ≥250 cells/mm³ 1

Secondary Prophylaxis (After SBP Episode)

Standard Regimen

All patients recovering from an episode of SBP must receive continuous prophylaxis with norfloxacin 400 mg once daily (or ciprofloxacin 500 mg once daily) indefinitely until liver transplantation or resolution of ascites. 1, 2, 5

Evidence for Secondary Prophylaxis

• Without prophylaxis, the cumulative recurrence rate at one year is approximately 70%, which norfloxacin reduces to 20% 1, 2
• Norfloxacin reduces SBP due to gram-negative bacilli from 60% to 3% 1
• One-year survival after SBP is only 30-50%, falling to 25-30% at two years, making prophylaxis critical 1, 2

Alternative Agents

• Ciprofloxacin 500 mg once daily is an acceptable alternative commonly used in the UK 1, 2, 5
• Rifaximin 550 mg twice daily is more effective than norfloxacin for secondary prophylaxis, with significantly lower SBP recurrence (7% vs 39%) and fewer adverse events 6, 7
• Co-trimoxazole (800/160 mg once daily) is another alternative for patients intolerant to fluoroquinolones 2

Primary Prophylaxis (No Prior SBP)

High-Risk Patients Requiring Prophylaxis

Norfloxacin 400 mg daily should be given to patients with:

• Ascitic fluid protein <15 g/L (or <10 g/L per some guidelines) AND advanced liver disease 2, 5, 8
• Child-Pugh score ≥9 points 2, 5
• Serum bilirubin ≥3 mg/dL 5
• Impaired renal function or hyponatremia 2

Evidence for Primary Prophylaxis

• Norfloxacin reduces the one-year probability of developing SBP from 61% to 7% in high-risk patients 2
• It improves three-month survival probability from 62% to 94% 2
• Primary prophylaxis with norfloxacin for 6 months effectively prevents gram-negative bacilli infections in patients with low ascitic protein 8

Special Situation: Gastrointestinal Bleeding

All cirrhotic patients with acute gastrointestinal bleeding require antibiotic prophylaxis, as bacterial infections occur in 25-65% of these patients and significantly increase mortality 5

Regimen Selection

• IV ceftriaxone 1g daily for 7 days for patients with advanced liver disease 5
• Norfloxacin 400 mg orally twice daily for 7 days is an alternative for less severe disease 5

Important Caveats and Pitfalls

Resistance Concerns

• Long-term quinolone prophylaxis increases risk of gram-positive bacterial infections (79%), including methicillin-resistant Staphylococcus aureus, compared to predominantly gram-negative infections (67%) in those not on prophylaxis 1, 2, 5
• Avoid fluoroquinolones in patients already on quinolone prophylaxis for SBP, as this increases risk of resistant organisms 4
• Consider local bacterial resistance patterns when selecting prophylactic antibiotics 2, 5
• Avoid weekly ciprofloxacin regimens despite one study showing non-inferiority, as they may lead to higher rates of quinolone-resistant organisms 2, 9

Monitoring Requirements

• Be vigilant for fluoroquinolone-associated tendon complications, particularly in patients with renal impairment, and discontinue at first sign of tendon pain 4, 2
• Regular monitoring of renal function is recommended in patients on prophylactic antibiotics 2
• Perform diagnostic paracentesis if clinical deterioration occurs despite prophylaxis 2

Additional Considerations

• Restrict proton pump inhibitor (PPI) use in cirrhotic patients, as PPIs may increase SBP risk 2, 5
• All patients with SBP (current or prior) should be considered for liver transplantation evaluation due to poor long-term survival 1, 2, 5

Monomicrobial Bacterascites

• If cultures are positive but ascitic neutrophil count is normal (<250 cells/mm³) and the patient is asymptomatic, repeat the tap with neutrophil count rather than treating immediately 1
• Most cases are eradicated by natural defense mechanisms 1