What is the oral antibiotic coverage for Spontaneous Bacterial Peritonitis (SBP)?

Oral Antibiotic Coverage for Spontaneous Bacterial Peritonitis

For uncomplicated community-acquired SBP in clinically stable patients, oral ofloxacin 400 mg every 12 hours achieves 84% infection resolution comparable to IV cefotaxime, but this option is ONLY appropriate for highly selected patients without renal failure, hepatic encephalopathy, gastrointestinal bleeding, ileus, or shock. 1, 2

Critical Patient Selection Criteria for Oral Therapy

You can ONLY use oral antibiotics if ALL of the following are met:

• Community-acquired SBP (not nosocomial or healthcare-associated) 2
• Clinically stable without sepsis or septic shock 2
• No renal failure (creatinine <88 μmol/L) 1, 2
• No hepatic encephalopathy 1, 2
• No gastrointestinal bleeding 1, 2
• No ileus or shock 1, 2
• No recent broad-spectrum antibiotic exposure 2
• Not on quinolone prophylaxis 2

Oral Antibiotic Options

First-Line Oral Option

• Ofloxacin 400 mg PO every 12 hours for 5-7 days achieves infection resolution in 84% of cases, equivalent to IV cefotaxime 1, 2

Alternative Oral Options

• Ciprofloxacin 500 mg PO every 12 hours for 5-7 days can be used for uncomplicated community-acquired SBP or as step-down therapy after 2 days of IV ciprofloxacin 1, 2
• Amoxicillin/clavulanic acid can be switched to oral (0.5g/0.125g PO every 8 hours) after initial IV dosing, achieving 87% resolution rates 2

Mandatory Adjunctive Therapy Regardless of Oral vs IV Route

You MUST give IV albumin even when using oral antibiotics:

• 1.5 g/kg at diagnosis, then 1.0 g/kg on day 3 2
• This reduces hepatorenal syndrome from 30% to 10% and mortality from 29% to 10% 2
• This is non-negotiable and cannot be given orally 2

Treatment Monitoring Algorithm

At 48 Hours:

• Repeat paracentesis to assess ascitic neutrophil count 2
• Treatment success: PMN count decreased to <25% of pre-treatment value 1, 2
• Treatment failure: PMN count fails to decrease adequately—switch to IV broad-spectrum coverage and investigate for secondary peritonitis 2

Critical Pitfalls to Avoid

• Never delay antibiotics waiting for culture results—empirical therapy must start immediately 2
• Do not use oral antibiotics in nosocomial SBP (35% MDRO rate requires IV meropenem plus daptomycin) 2
• Do not use oral therapy in patients already on quinolone prophylaxis due to resistance 2
• Avoid aminoglycosides (tobramycin) due to nephrotoxicity 1, 2
• Do not skip IV albumin even when using oral antibiotics—this is where the mortality benefit comes from 2

When Oral Therapy is NOT Appropriate

If the patient fails ANY of the selection criteria above, use IV cefotaxime 2g every 8-12 hours (4g/day is as effective as 8g/day) for 5-7 days, which achieves 77-98% infection resolution 1, 2

Secondary Prophylaxis After Treatment

All patients surviving SBP require indefinite oral prophylaxis:

• Ciprofloxacin 500 mg PO once daily reduces 1-year SBP recurrence from 68% to 20% 3, 2
• Alternative: Norfloxacin 400 mg PO once daily 3
• Continue until liver transplantation or definitive resolution of ascites 3