Background

The population of new patients with end-stage kidney disease (ESKD) receiving dialysis in Taiwan increased from 10,697 in 2013 to 11,596 in 2016. According to the 2018 Annual Report on Kidney Disease in Taiwan, the proportion of new patients with ESKD receiving hemodialysis was 88.9% in 2013, but it increased to 89.7% in 2016. The establishment of a well-functioning vascular access (VA) procedure is fundamental to enabling patients to undergo an efficient hemodialysis procedure. Although infection related to VA is not common, it is a problematic complication that may lead to access loss, sepsis, and even death. The major types of VA conduits commonly used are native arteriovenous fistulas (AVFs), prosthetic arteriovenous grafts (AVGs), and central venous catheters (CVCs; both temporary and cuffed tunneled). AVFs and AVGs are preferred over CVCs for dialysis access because CVCs expose patients undergoing hemodialysis to an increased risk of healthcare-associated infections (1). Pathogens primarily responsible for CVC-related infections are Staphylococcus , Gram-negative enteric bacilli, Pseudomonas aeruginosa , and Candida spp. These pathogens can form a biofilm on the CVC walls, rendering them strongly resistant to antibiotic action (2). The mechanism underlying VA infections (VAIs) generally involves the migration of surface organisms along the external surface of the catheter from the exit-site wound or through the lumen of the catheter. Staphylococcus aureus and coagulase-negative staphylococcus (CoNS) species are the most frequently isolated bacteria from VAIs.
S. aureus is among the most common causes of both endemic and epidemic infections acquired in hospitals. Patients undergoing hemodialysis are frequently exposed to S. aureus during their stay in dialysis centers, hospitals, or rest homes; the VA site for hemodialysis is a potential site of entry for the pathogen, and the risk of infection is particularly high when a CVC is used (3, 4). Furthermore, recent research has reported that CoNS species as the most common etiology of nosocomial bloodstream infection (BSI), especially CVC-related BSI (CRBSI), in hospitalized patients (5-7).
P. aeruginosa is a major cause of nosocomial infection, particularly in immunocompromised patients. It has a predilection for moist environments that serve as its natural reservoirs; therefore,P. aeruginosa is a common pathogen in graft infection (8, 9).
We conducted a 5-year single-institution study to (1) investigate the prevalence of bacterial species from VAI (2) determine the molecular characteristics of different bacterial species isolated from various types of VAIs, and (3) establish the correlation between bacterial species, sequence types (STs), and VAI types.