What is the antibiotic (Abx) of choice for spontaneous bacterial peritonitis?

From the Guidelines

The antibiotic of choice for spontaneous bacterial peritonitis (SBP) is a third-generation cephalosporin, specifically cefotaxime 2g IV every 8 hours, due to its excellent coverage against the most common causative organisms in SBP, as supported by the most recent and highest quality study 1.

Key Considerations

• The choice of antibiotic should be based on the severity of the infection and the local resistance profile, with consideration of the environment of the infection (community-acquired, healthcare-associated, or nosocomial) 1.
• In patients with healthcare-associated SBP or recent antibiotic exposure, broader coverage with piperacillin-tazobactam 4.5g IV every 6 hours or meropenem 1g IV every 8 hours may be necessary due to the risk of resistant organisms 1.
• Treatment should be initiated immediately after diagnostic paracentesis when SBP is suspected, without waiting for culture results, and albumin administration (1.5 g/kg on day 1 and 1 g/kg on day 3) is also recommended alongside antibiotics in patients with renal dysfunction or severe liver disease to prevent hepatorenal syndrome 1.

Alternative Options

• Amoxicillin/clavulanic acid, first given intravenously then orally, has similar results with respect to SBP resolution and mortality as cefotaxime, but with a lower cost, although its use is associated with a high rate of drug-induced liver injury (DILI) 1.
• Ciprofloxacin, given either intravenously or orally, results in a similar SBP resolution rate and hospital survival as cefotaxime, but with a significantly higher cost, although switch therapy with ciprofloxacin is more cost-effective than intravenous cefotaxime 1.

Monitoring and Adjustment

• If ascitic fluid neutrophil count fails to decrease to less than 25% of the pre-treatment value after 2 days of antibiotic treatment, further evaluation is necessary, and consideration of alternative antibiotics or additional treatments may be required 1.

From the Research

Antibiotic Treatment for Spontaneous Bacterial Peritonitis

• The choice of antibiotic for spontaneous bacterial peritonitis (SBP) depends on various factors, including the severity of the infection, the presence of multidrug-resistant organisms, and the patient's underlying liver disease 2, 3, 4, 5, 6.
• Third-generation cephalosporins, such as cefotaxime, are commonly recommended as the first-line treatment for SBP due to their broad-spectrum activity against gram-negative bacteria, including Escherichia coli, Klebsiella spp, and Streptococcus spp 3.
• However, the emergence of multidrug-resistant organisms has led to an increased use of alternative antibiotics, such as carbapenems, which have been shown to be effective in treating SBP, particularly in patients with severe liver disease or those who have failed to respond to third-generation cephalosporins 4, 6.
• A study published in 2021 found that empirical treatment with carbapenem did not reduce in-hospital mortality compared to treatment with third-generation cephalosporins in patients with SBP, but carbapenem treatment was associated with lower in-hospital mortality in critically ill patients with high chronic liver failure-sequential organ failure assessment (CLIF-SOFA) scores 4.
• Another study published in 2019 found that initiation of a carbapenem significantly reduced all-cause mortality compared to a third-generation cephalosporin as an initial antibiotic of choice in recurrent SBP 6.
• The choice of antibiotic should be guided by the patient's clinical presentation, the results of ascitic fluid cultures, and the local antimicrobial susceptibility patterns 2, 5.

Factors Influencing Antibiotic Choice

• The presence of multidrug-resistant organisms, such as gram-positive cocci (GPC) and multi-resistant bacteria, can influence the choice of antibiotic 2.
• The severity of the underlying liver disease, as measured by the CLIF-SOFA score, can also impact the choice of antibiotic 4.
• The use of acid suppressive and beta-adrenergic antagonist therapies has been associated with an increased risk of SBP, and withholding these medications may be considered in patients with SBP 2.
• The use of selective albumin supplementation remains an important adjunct in SBP treatment 2, 3.