Sporadic culture-negative peritonitis in peritoneal dialysis patients--absence of endotoxin in dialysate

Nephron Clin Pract. 2008;108(1):c1-4. doi: 10.1159/000112042. Epub 2007 Dec 6.


Background: Indiscriminate use of broad-spectrum antibiotics in peritonitis may have either unwanted side effects or contribute to the development of antibiotic resistance. It is tempting to use broad-spectrum antibiotics in cases of culture-negative peritonitis. This study examines whether Gram-negative agents have to be considered in the management of culture-negative peritonitis. Gram-negative agents are manifested by endotoxin easily detected by the Limulus amebocyte lysate (LAL) test.

Methods: 138 episodes of Gram-negative and culture-negative peritonitis have been retrospectively analyzed; episodes of Gram-negative peritonitis were controls. Correlation between LAL and culture results was compared between the two groups. The LAL test was performed using a commercial kit by incubating a mixture of dialysate effluent and LAL reagent at 37 degrees C. Development of a stable solid clot was considered positive.

Results: In controls, 80 out of 117 Gram-negative peritonitis were LAL positive (68%). None of the 21 culture-negative episodes was LAL positive. In 7 recurrences of Gram-negative peritonitis, the LAL test turned from negative to positive but in none of the recurrences of culture-negative peritonitis. The difference in correlation was highly significant.

Conclusions: Gram-negative organisms do not seem to be involved in sporadic culture-negative peritonitis. In episodes of peritonitis in which bacteriologic cultures stay negative for 48 h, initial coverage of Gram-negative organisms may be dropped.

Publication types

  • Comparative Study

MeSH terms

  • Colony Count, Microbial / methods
  • Dialysis Solutions / isolation & purification*
  • Endotoxins / isolation & purification*
  • Endotoxins / physiology
  • Female
  • Gram-Negative Bacteria / growth & development
  • Gram-Negative Bacteria / isolation & purification*
  • Humans
  • Male
  • Middle Aged
  • Peritoneal Dialysis* / standards
  • Peritonitis / diagnosis
  • Peritonitis / microbiology*
  • Peritonitis / therapy
  • Recurrence
  • Retrospective Studies
  • Time Factors


  • Dialysis Solutions
  • Endotoxins