Peritoneal dialysis (PD) is the first-line treatment of end stage renal disease (ESRD) in Hong Kong. Despite the advances in antibiotic therapy and connecting system, recurrent peritonitis remains the major cause of peritoneal failure. A reliable predictor of relapsing peritonitis is invaluable in the management of PD peritonitis. Recent studies showed that bacterial-derived lipopolysaccharide (LPS) fragments are present in clinically used fluids such as dialysis fluid. LPS are thought to be derived from microorganisms inhabiting body fluid. The investigators hypothesize that the presence of LPS in PD effluent is a predictor of relapsing peritonitis in PD patients. The investigators plan to study 300 patients with PD peritonitis. After inform consent, specimens of PD effluent will be collected on the day of initiating antibiotic treatment, every 5 days until the day of completing antibiotic treatment, and then 28 days later for the test of LPS level. All patients will be followed for one year after completion of antibiotic therapy for the development of relapsing, recurrent, or repeat peritonitis episodes. Our study would explore the use of detecting LPS in PD effluent as a non-invasive tests for the prediction of relapsing peritonitis.

Inclusion Criteria:

at least two of the followings:

1. abdominal pain or cloudy PD effluent;
2. leukocytosis in PD effluent (WBC > 100/ml); and
3. positive Gram-stain or culture from PD effluent

Exclusion Criteria:

• mycobacterial peritonitis
• obvious surgical problems and require laparotomy