Reduction of Symptomatic Catheter-Associated Urinary Tract Infections Using Silver-Alloy Coated Foley Catheters in a Large Health System

Background: Catheter-associated urinary tract infections (CAUTIs) are associated with increased morbidity, mortality, and cost.  Multiple strategies have been recommended to reduce CAUTIs and include both technique (i.e. early catheter removal) and technology (i.e. anti-infective catheters).  Most effectiveness data for CAUTI prevention strategies were based on or included asymptomatic bacteriuria (ASB).  Ongoing controversy exists as to whether ASB represents a clinically significant condition and new National Healthcare Safety Network (NHSN) surveillance definitions do not include them.

Objective: To evaluate the clinical efficacy of a silver-alloy and hydrogel coated Foley catheter in four facilities in a large health system using both symptomatic catheter-associated urinary tract infections (SCAUTI) and ASB plus SCAUTI surveillance definitions.

Methods: Using a time-series study design, SCAUTIs and ASBs occurring in adult patients in medical/surgical and critical care units were identified using standard infection surveillance methods.  In time period 1 all patients received a standard Foley catheter; in time period 2 all patients received a silver-alloy coated catheter.  Each period lasted 3 months.  Study facilities ranged in size (350 beds – 673 beds), type (community, teaching) and services offered (e.g. burn center, transplants, etc).  A total of 610 patients met inclusion criteria for the study.

Results: In time period 1 (standard catheters) 106 ASBs and 93 SCAUTIs were identified with a total of 102,335 patient days.  In time period 2 (silver alloy coated catheters) 92 ASBs and 49 SCAUTIs were identified with a total of 106,398 patient days.  Overall CAUTI rates (symptomatic and asymptomatic) were 1.94/1,000 patient vs. 1.32/1,000 patient days in periods 1 and 2 respectively (p=<0.001, 95%CI).  SCAUTI rates were 0.91/1,000 patient days vs. 0.46/1,000 patient days (p=<0.001, 95%CI).  There were no significant differences in age, length of stay, average length of catheterization or gender in patients with CAUTI between the two time periods.  There were no significant differences in organisms causing CAUTIs between time periods (56% Gram-negative, 23% Gram-positive, 21% Yeast).

Conclusions: The use of silver alloy-coated Foley resulted in a relative reduction in overall CAUTI rates of 32%.  More importantly, the use of silver alloy-coated Foley catheters resulted in a 49% relative reduction in symptomatic catheter-associated urinary tract infections.  This study demonstrated that the implementation of anti-infective Foley catheters is clinically efficacious and likely translates to improved patient outcomes and safety.