What is the most common organism causing Spontaneous Bacterial Peritonitis (SBP)?

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From the Guidelines

Escherichia coli is the most common organism causing Spontaneous Bacterial Peritonitis (SBP).

Causative Organisms

  • The most common pathogens include Gram-negative bacteria (GNB), usually Escherichia coli and Gram-positive cocci (mainly streptococcus species and enterococci) 1.
  • Escherichia coli, Klebsiella pneumoniae, and Streptococcus are the most commonly identified bacteria in culture 1.

Treatment

  • Third-generation cephalosporin antibiotics, such as cefotaxime and ceftriaxone, are recommended as they are effective for most causative bacterial pathogens, including Escherichia coli 1.
  • The standard treatment duration is 5 to 10 days, but may vary according to symptoms and/or results of antimicrobial susceptibility testing 1.

From the Research

Causative Organisms of Spontaneous Bacterial Peritonitis (SBP)

The most common organisms causing SBP are:

  • Gram-negative bacteria, such as Escherichia coli and Klebsiella species 2, 3, 4
  • Specifically, E. coli is the major pathogen, followed by Klebsiella pneumoniae and Enterococcus faecium 3
  • Gram-positive bacteria, such as Enterococcus, are also increasingly involved in SBP, particularly in nosocomial infections 3, 5

Variation in Causative Organisms by Population

  • In children with liver disease and ascites, the most common cause of SBP is Streptococcus pneumoniae, followed by E. coli and other organisms 6
  • In adults, the most common causes of SBP are E. coli, Klebsiella pneumoniae, and Enterococcus faecium 2, 3, 4

Antibiotic Resistance and Treatment

  • The increasing involvement of multi-drug resistant bacteria in SBP is a concern, and treatment regimens should take into account the acquisition site of infection and local epidemiological situation 3, 5
  • Empirical antibiotic therapy should be started immediately in patients with SBP, and third-generation cephalosporins, such as cefotaxime or ceftriaxone, are recommended as first-line treatment 2, 4, 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

[Spontaneous Bacterial Peritonitis].

The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi, 2018

Research

Spontaneous bacterial peritonitis: pathogenesis, diagnosis, treatment.

Journal of gastrointestinal and liver diseases : JGLD, 2006

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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