Intraleukocytic sequestration as a cause of persistent Staphylococcus aureus peritonitis in continuous ambulatory peritoneal dialysis.

Peritonitis caused by Staphylococcus aureus in four patients undergoing continuous ambulatory peritoneal dialysis failed to respond to, or relapsed immediately after cessation of, intraperitoneal antibiotic therapy with vancomycin or cephalothin and tobramycin. Sequestration of viable staphylococci within polymorphonuclear leukocytes in the peritoneal fluid was suspected for two reasons: (1) staphylococci could still be grown after treatment of the dialysate cell fraction with lysostaphin, a procedure that kills only extracellular staphylococci, and (2) diminished polymorphonuclear leukocyte bactericidal activity was demonstrated in peritoneal dialysis effluent. Addition of rifampin, which readily penetrates polymorphonuclear leukocytes, to the treatment regimen of all patients led to prompt resolution of peritonitis without relapse.