A prospective study of hemodialysis access-related bacterial infections

Abstract

The objective of this study was to describe hemodialysis vascular-access related infections that occurred in hemodialysis patients over an 18-month period. The study is a prospective descriptive analysis of incidence infection rates in a hemodialysis unit in a tertiary-care medical center. Prospective surveillance for hemodialysis vascular access-related infection was performed for all patients undergoing hemodialysis from November 1999 through April 2001 at King Fahd Hospital of King Faisal University, Al-Khobar, Saudi Arabia. The total number of dialysis sessions was calculated. The type of vascular access was noted. Cultures were obtained and all infections were recorded and infection rates were calculated. There were 9627 hemodialysis sessions (5437 via permanent fistulae or grafts, 2409 via temporary central catheters, and 1781 via permanent tunneled catheters) during the 18-month study period. We identified a total of 109 infections, for a rate of 11.32/1000 dialysis sessions (ds). Of the 109, 23 involved permanent fistulae or grafts (4.23/1000 ds); 18 involved permanent-tunneled central catheter infections (10.1/1000 ds); and 68 involved temporary-catheter infections (28.23/1000 ds). There were 38 bloodstream infections (3.95/1000 ds) and 34 episodes of clinical sepsis (3.53/1000 ds). Seventy-one vascular access infections without bacteremia were identified (7.38/1000 ds), including 16 permanent-fistulae or graft infections (2.94/1000 ds), 7 permanent-tunneled central catheter infections (3.93/1000 ds), and 48 temporary-catheter infections (19.92/1000 ds). Staphylococcal organisms were responsible for 77% of the infections, with Staphylococcus epidermidis being the strain most commonly implicated. Gram-negative organisms were responsible for 23% of the infections. In conclusion, infection rates were highest in hemodialysis patients with temporary vascular access, compared with rates in those with permanent arteriovenous fistulae and synthetic grafts. Most of the bacterial organisms isolated from the vascular access sites were gram-positive cocci, with S. epidermidis accounting for 50% of the organisms. The rate of infection with gram-negative bacilli was higher than in other reports. Our greater dependence on central venous catheters, due to local factors, coupled with the immune-compromising comorbid conditions of our patients, may be contributory to the pattern of infection reported. Delays in the creation of vascular grafts for hemodialysis access should be avoided.