Method for studying development of colonization and infection of dialysis catheters.

Microbial colonization and infection of dialysis catheters is the major cause of catheter failure. The present study aimed to develop a method to permit the study of microbial biofilm formation and antibiotic prophylaxis and therapy. Standard silicon rubber and silver-impregnated catheters were sectioned into 1 mm slices and placed into 1-cm x 2-cm culture slide chambers. Fresh clinical isolates were obtained from infected patients and suspended in concentrations of 10(3), 10(6), and 10(9) colony forming units (CFU) per milliliter in a variety of liquid suspending culture media, which included serum protein constituents. Antibiotics could be added to the suspending fluid to determine prophylactic activity, or at any time thereafter to determine therapeutic activity. The catheter sections were incubated with the microbial challenge for 6 hours, 12 hours, 24 hours, and 48 hours and then washed in flowing distilled water to remove unattached biofilm. They were then stained with acridine orange, which fluoresces microbial DNA, and were examined by confocal scanning laser microscopy. Biofilm formation, representing colonization and infection, were quantified by comparing the fluorescent pixel analysis of the uninoculated control with the challenged catheter. The method was reproducible and permitted quantitative analysis. Standard silicon rubber catheters demonstrated greater biofilm formation than silver-impregnated catheters. The method examines the factors involved in microbial colonization and infection, and in antibiotic prophylaxis and therapy.

Continuous peritoneal dialysis and the extended care facility.

The projected disproportionate increase in the number of elderly patients reaching end-stage renal disease constitutes a dramatic change in dialysis demographics. The nursing home or extended care facility (ECF) will become an increasingly important feature of care for both rehabilitation and long-term patient management. For continuous peritoneal dialysis (CPD), the ECF has been critically evaluated in only a single specialized, university-based, geriatric facility that included trained peritoneal dialysis nurses providing care. We have trained multiple ECF personnel in 10 community-based ECFs to provide all CPD-related therapy for 93 patients between November 1993 and December 1998, for a total of 289.3 patient-months. All ECFs have maintained their CPD program. Outcome measures, including hospitalization, mortality, technique failure, and peritonitis rates, show the success and feasibility of using community-based ECFs for CPD. The use of multiple ECFs for CPD appears to offer distinct advantages over solo structured ECF programs without jeopardizing outcomes. A highly structured CPD education program for ECF personnel by nephrology staff is manageable and appears critical for the success of maintaining CPD in the ECF.

Bilateral renal infarction secondary to paradoxical embolism.

Paradoxical embolism is an uncommon but increasingly reported cause of arterial embolic events. Involvement of the kidney is rarely reported. Autopsy studies suggest, however, that embolic renal infarction is underdiagnosed antemortem. We report a case of bilateral, main renal artery occlusion and acute renal failure secondary to paradoxical embolism. Clinical and laboratory data at presentation were not suggestive of renal infarction. Support for the diagnosis of paradoxical embolism, which most commonly occurs across a patent foramen ovale, was made by contrast echocardiography, which provides a sensitive method for detecting right-to-left intracardiac shunts. The often subtle presentation of renal infarction suggests patients with peripheral or central arterial embolic events should be carefully observed for occult renal involvement. Contrast echocardiography should be performed when renal infarction occurs without a clear embolic source to evaluate for paradoxical embolism.