Pseudomonas peritonitis in continuous ambulatory peritoneal dialysis: laboratory predictors of treatment failure.

Five episodes of pseudomonas peritonitis complicating continuous ambulatory peritoneal dialysis (CAPD) which were not cured by intraperitoneal antibiotics were studied to assess causes for treatment failure. The activity of gentamicin and ceftazidime against these strains was decreased in the presence of sterile used dialysate compared with nutrient broth. Likewise, kinetic studies showed that in dialysate therapeutically used concentrations of antibiotics failed to kill the isolates over 24 h. All five pseudomonas strains were adherent to silicone rubber Tenckoff catheter segments. An in vitro model of CAPD peritonitis demonstrated that persistence of viable adherent bacteria, after exposure to therapeutic concentrations of gentamicin and ceftazidime, contributes to the failure of antibiotics to cure pseudomonas CAPD peritonitis.