What is the recommended antibiotic and albumin regimen for treating spontaneous bacterial peritonitis in a cirrhotic patient with ascites, including options for resistant organisms, beta‑lactam allergy, and secondary prophylaxis?

Treatment of Spontaneous Bacterial Peritonitis

First-Line Antibiotic Therapy

For community-acquired SBP, initiate intravenous cefotaxime 2 g every 8 hours or ceftriaxone 1–2 g every 12–24 hours immediately upon diagnosis, without waiting for culture results. 1, 2

• Third-generation cephalosporins achieve infection resolution rates of 77–98% for cefotaxime and 73–100% for ceftriaxone in community-acquired cases. 1, 2
• A total daily dose of 4 g cefotaxime (2 g every 12 hours) is as effective as 8 g/day, though every-8-hour dosing provides more consistent coverage in severe presentations. 1, 2
• Standard treatment duration is 5 days for uncomplicated SBP; extending to 10 days offers no additional benefit. 1, 2

Mandatory Adjunctive Albumin Therapy

Administer intravenous albumin 1.5 g/kg within 6 hours of diagnosis, followed by 1.0 g/kg on day 3, for any patient with serum creatinine ≥1 mg/dL, blood urea nitrogen ≥30 mg/dL, or total bilirubin ≥4 mg/dL. 2, 3

• This regimen reduces mortality from 29% to 10% and prevents hepatorenal syndrome (decreasing incidence from 30% to 10%). 2, 3
• Albumin is superior to hydroxyethyl starch for this indication. 2

Alternative Antibiotics for Specific Scenarios

Beta-Lactam Allergy or Uncomplicated Cases

• Oral ofloxacin 400 mg twice daily may replace IV cefotaxime only in patients with uncomplicated community-acquired SBP who have no prior quinolone exposure, no vomiting, no shock, no grade II or higher hepatic encephalopathy, and serum creatinine <3 mg/dL. 2, 3
• This oral strategy applies to approximately 60% of SBP cases. 2
• Ciprofloxacin 200 mg IV every 12 hours for 2 days followed by 500 mg orally every 12 hours for 5 days is a cost-effective switch therapy option for uncomplicated cases. 1, 2

Nosocomial or Healthcare-Associated SBP

For hospital-acquired SBP, use meropenem 1 g IV every 8 hours plus daptomycin 6 mg/kg/day as empirical therapy. 2, 4

• This combination achieves 86.7% resolution versus 25% with ceftazidime in nosocomial SBP. 4
• Nosocomial SBP carries a 35–54% rate of multidrug-resistant organisms, including extended-spectrum beta-lactamase (ESBL)-producing bacteria and quinolone-resistant strains. 2, 4, 5
• Consider broader coverage for patients with recent hospitalization, ICU admission, or septic shock. 2

Contraindications to Specific Agents

• Never use aminoglycosides (tobramycin, gentamicin) as empirical therapy due to nephrotoxicity and inferior efficacy compared to cefotaxime. 1, 3
• Avoid quinolones as first-line agents in patients on quinolone prophylaxis, those with severe presentations (shock, renal failure, encephalopathy, GI bleeding), or nosocomial acquisition. 2, 3

Monitoring Treatment Response

Perform repeat diagnostic paracentesis at 48 hours to assess treatment efficacy. 1, 2

• Treatment success is defined as a ≥75% reduction in ascitic neutrophil count (i.e., PMN count <25% of baseline). 1, 2
• If PMN count fails to decrease by at least 25%, suspect treatment failure and broaden antimicrobial coverage. 1, 2
• Investigate for secondary bacterial peritonitis if ascitic total protein ≥1 g/dL, LDH above normal serum upper limit, glucose <50 mg/dL, or polymicrobial culture. 1, 2

Secondary Prophylaxis (Indefinite Duration)

All patients who survive an SBP episode must receive indefinite antibiotic prophylaxis until liver transplantation or death. 2, 3

• Without prophylaxis, the 1-year SBP recurrence rate exceeds 70%. 2
• Norfloxacin 400 mg orally once daily is the most extensively studied regimen, reducing recurrence from 68% to 20%. 2, 3
• Alternative regimens include ciprofloxacin 500 mg orally once daily or co-trimoxazole (800 mg sulfamethoxazole/160 mg trimethoprim) once daily. 2

Critical Pitfalls and Caveats

• Never delay antibiotics while awaiting culture results—empirical therapy must start immediately upon diagnosis (PMN count >250/mm³). 1, 3
• Distinguish secondary peritonitis from SBP using imaging (CT scan) when ≥2 of the following are present: protein >1 g/dL, elevated LDH, glucose <50 mg/dL, polymicrobial culture, or lack of PMN decrease after 48 hours. 1, 2
• In patients on quinolone prophylaxis who develop SBP, switch to third-generation cephalosporins due to high quinolone resistance rates. 2, 6
• Increasing resistance patterns, particularly in studies enrolling patients after 2008, suggest that local antimicrobial susceptibility data should guide therapy when available. 5
• Discontinue antibiotics once ascitic PMN count falls below 250/mm³, typically by day 4–5 of appropriate therapy. 2