TYPING OF COAGULASE-NEGATIVE STAPHYLOCOCCI FROM PERITONITIS IN CAPD PATIENTS BY THE PHP-CS SYSTEM AND REA

Coagulase-negative staphylococci (CNS) were the most common bacteria c ausing peritonitis in patients treated with continuous ambulatory peri toneal dialysis (CAPD). In order to investigate if the same clone was responsible for the peritonitis in the different patients and if the e xit site was the source of infection we followed 68 patients on CAPD f or 2 years. During this period 9 patients had 12 episodes of peritonit is caused by CNS. Cultures were taken from exit site and peritoneal fl uid in all patients at peritonitis and during the first study year at monthly intervals. In each culture up to 10 isolates of CNS were rando mly collected and frozen. All 437 CNS isolates from the patients with CNS peritonitis were typed using a biochemical typing method and 41 is olates identical by this method were further discriminated by a DNA fi ngerprinting method. Identical strains were in no case isolated from d ifferent patients, indicating that no virulent strain was spread betwe en the patients. The isolates causing the peritonitis were never found at the exit sites before the first day of the peritonitis in any pati ent. In only two patients was the same strain found at the exit site a nd in the peritoneal fluid on the first day of peritonitis. It thus se ems that no virulent clone of CNS was infecting the patients and we fo und no evidence of CNS at the exit site causing the peritonitis.