A Prospective Study on Incidence of Bacterial Infections in Portuguese Dialysis Units

Abstract

Background: Viral infection has been the main epidemiologic concern in the hemodialysis unit; however, bacterial infection is responsible for more than 30% of all causes of morbidity and mortality in our patients, vascular access infection being the culprit in 73% of all bacteremias. Methods: A prospective multicenter cohort study of bacterial infections incidence, conducted from January to July 2004 in five hemodialysis units, to record and track bacterial infections, using a validated database from CDC’s Dialysis Surveillance Network Program. Results: 4,501 patient-months (P-M) were surveilled, being dialyzed through a native fistula (AVF) in 60.6%, a graft (PTFE) in 31.3%, a tunneled catheter (TC) in 7.6%, and a transient catheter (C) in 0.5%. As target events, we registered 166 hospitalizations – 3.7/100 P-M (2.2/100 P-M in patients with AVF, 4 in PTFE, 9.9 in TC, and 19 in C), and 182 intravenous antibiotic courses. Of these 182 antibiotic treatments, 47.8% included vancomycin, only 30% had blood cultures drawn pretreatment, and only 36% were positive. We recorded 98 infections at the vascular access site 2.18/100 P-M (0.95 in AVF, 1.6 in PTFE, 12.6 in TC, and 42.85 in C) and 2.13 infections/100 P-M at other sites. The isolated microorganisms were Staphylococcus epidermidis in 40.1%, Staphylococcus aureus in 30.1%, Pseudomonas in 13.3%, and Escherichia coli in 3.3%. Although we found a diversity of practice patterns, the number of target events (8.4/100 P-M) and the bacterial infections incidence (4.31/100 P-M) were remarkably homogeneous in the five centers. Conclusion: (1) High incidence of bacterial infections, causing major morbidity; (2) infectious risk is vascular access type-dependent, with dramatic rise in catheters; (3) underutilization of blood cultures to orient diagnosis and therapy, and (4) high rates of vancomycin prescription.