*(a) Product contamination of the infusion.*

28 patients, 27 patients were on chronic HD and 1 in peritoneal dialysis (PD) patient. 40% of the HD patients were treated with AVF's and the AVF was the definite or suspected site of entry for the causative organism in eight cases of IE representing the 26.6% of the total of patients with IE. The presumption that the AVF was the source of bacteremia in these episodes is supported by the fact that the causative organism in seven episodes was commensal skin pathogens *Staphylococcus aureus* (*S. aureus*) in six patients and *Staphylococcus epidermidis* (*S. epidermidis*) in one patient [3]. In contrast, Jones et al. conducted a retrospective study between the years 1998 and 2011. Forty-two patients were identified with developed IE out of a total incident dialysis population of 1500 over 13 years. Ninety-five percent of patients (40/42) were on long-term HD and five percent (2/42) on PD. Mean patient age was 55.2 years (IQR: 43–69), and the mean duration of HD prior to IE was 57.4 months. Primary HD access at the time of diagnosis was an AVF in 35% (14/40), a dual-lumen tunneled catheter (DLTC) in 55% (22/40), and a dual-lumen nontunneled catheter (DLNTC) in 10% (4/40). *S. aureus*, including methicillin-resistant *S. aureus* (MRSA), was present in 57.1%

Dialysis is a well-established risk factor for IE. Mylonakis et al. reported that end-stage renal disease in HD patients has a higher rate of morbidity and mortality compared to general population. Infections are the major cause of morbidity and mortality and are the second leading cause of death in HD patients surpassed only by cardiovascular disease. And these

The mortality rate in patients with IE ranges from 30 to 56% in one year and in-hospital

One of the factors that increase the risk of developing IE in HD patients is bacteremia, which are exposed to repetitive vascular access through an arteriovenous fistula (AVF), polytetrafluoroethylene (PTFE) grafts or percutaneous catheters for HD, or cuffed or

The incidence of bacteremia is related to vascular access type, ranging from 1.6 to 7.7 per 1000 days with percutaneous catheters and 0.2 to 0.5 per 1000 days with AVF, according to the

The use of catheters during HD is the leading cause of bacteremia in HD patients [4, 8, 15, 18]. A hierarchy of bacteremia risk exists among various types of HD vascular access; it is less common in patients with native arteriovenous fistulae, while synthetic grafts, cuffed catheters,

These episodes of bacteremia during HD are relatively common. They can be endogenous or exogenous: through the microorganism flora found in the patient (endogenous) or through

(24/42) [14, 15].

124 Contemporary Challenges in Endocarditis

**4. IE risk factors in dialysis patients**

occur in about 12–22% of ESRD patients [15–17].

**4.1. HD-related bacteremia**

noncuffed dual lumen catheter.

reference.

mortality is twice more frequent than the general population with IE.

and uncuffed catheters yield a progressively increasing risk.

Contamination of parenteral fluids is exceptional at the present time due to the rigorous control sterility and subject to quick degradation once the expiration date is reached. In these cases, bacteremia usually caused by Gram-negative bacteria (Enterobacteriaceae or nonfermenting Gram-negative bacilli) particularly serious and epidemic type may occur.

#### *(b) Contamination of connection and intraluminal space.*

Contamination of the connection point of vascular catheters is the second most common cause of arrival of microorganisms to the bloodstream (after related to the place of insertion) and the most common involved in intravascular devices longer than 2 weeks. It is, therefore, the usual way of colonization of CVC, whether or not tunneled, when it occurs after 2 weeks from implantation. In this way, microorganism colonizations progress through the intraluminal surface of catheters, forming biofilm colonization all the way from the outside end to the intravascular end.
