INCIDENCE AND NATURE OF PERITONEAL CATHETER BIOFILM DETERMINED BY ELECTRON AND CONFOCAL LASER-SCANNING MICROSCOPY

Thirty-two Tenckhoff catheters retrieved from continuous ambulatory pe ritoneal dialysis patients with a history of peritonitis were examined for microbial biofilm. Confocal laser scanning microscopy was success fully employed to visualize bacteria in biofilm occluded from view by scanning electron microscopy. Occluded but viable microbial biofilm wa s associated with 17 (81%) catheters from patients free from infection following renal transplant. Mixed isolate biofilm with two or more is olates of coagulase-negative staphylococci or Staphylococcus aureus wa s found on 41% of these catheters. Clearly visible viable biofilm cons isting exclusively of Pseudomonas aeruginosa occurred on all four cath eters removed due to recurrent peritonitis. Five (71%) catheters retri eved from patients transferred to haemodialysis had viable biofilm. An tibiotic sensitivities of the biofilm isolates were similar in profile to those reported for non-biofilm isolates from infected dialysate. P ersistence of catheter biofilm despite direct contact with therapeutic levels of antibiotics in peritoneal dialysate requires that attention be directed towards improving antibiotic efficacy against peritonitis -causing bacteria in biofilm form.