Microbiological aspects of peritonitis in patients undergoing chronic peritoneal dialysis at the dialysis unit of Sri Jayawardenapura General Hospital.

Background: Peritoneal dialysis (PD) is an established form of therapy in the management of end stage renal disease. Peritonitis is the main complication of PD.

Objectives: To study the incidence and microbial aetiology of peritonitis in patients undergoing chronic PD at the dialysis unit of Sri Jayewardenapura General Hospital (SJGH); to assess the diagnostic value of the Gram's stain; and to study the relationship of the total white cell count of effluent to peritonitis.

Design: A prospective study over three months.

Setting: Dialysis unit of SJGH.

Patient Population: The study involved 18 patients undergoing manual intermittent peritoneal dialysis (IPD), 4 patients undergoing chronic ambulatory peritoneal dialysis (CAPD), and 1 patient undergoing nocturnal intermittent peritoneal dialysis (NIPD).

Measurements: Clinical presentation of patients with peritonitis; total and differential white blood cell counts of effluent samples; Gram stain and culture of the centrifuged deposit to determine microbial aetiology; incidence of peritonitis in different categories of dialysis.

Results: 32 samples were examined from patients on IPD, and 17 from patients on CAPD. In IPD most episodes were due to Gram negative organisms whereas in CAPD most episodes were due to Gram positive organisms. Sensitivity of Gram's stain in relation to culture was 32.4%. 98% of effluent samples had white blood cell counts of > 100/ml and none showed neutrophil counts of < 49%.

Conclusions: The incidence of IPD associated peritonitis was 11.1 episodes per patient year, and the incidence of CAPD associated peritonitis was 14 episodes per patient year. Flavobacterium spp. were the predominant organisms in IPD associated peritonitis, whereas CAPD associated peritonitis was commonly caused by coagulase negative staphylococci. Gram's stain was not useful in the initial identification of the causative agent, but the white cell and neutrophil counts were found to be sensitive indicators of peritonitis.