Intravascular catheters represent an essential part of the management of critically and chronically ill patients. However, their use is often complicated by serious infections, mostly catheter-related bloodstream infections (CRBSIs), which are associated with increased morbidity, duration of hospitalisation, and additional medical costs. The incidence of CRBSI varies considerably by type of catheter, frequency of catheter manipulation and patient-related factors, such as underlying disease and severity of illness 1. However, the majority of CRBSIs are associated with central venous catheters (CVCs) 1, and in prospective studies the relative risk for CRBSI is up to 64 times greater with CVCs than with peripheral venous catheters 234.

Different measures have been implemented to reduce the risk for CRBSI, including use of maximal barrier precautions during catheter insertion, effective cutaneous antisepsis, and preventive strategies based on inhibiting microorganisms originating from the skin or catheter hub from adhering to the catheter. Institution of continuous quality improvement programs, education and training of health care workers, and adherence to standardized protocols for insertion and maintenance of intravascular catheters significantly reduced the incidence of catheter-related infections and represent the most important preventive measures 12. In the present review the new technologies for prevention of infections directed at CVCs, which have been shown to reduce the risk of CRBSI, including catheters and dressings impregnated with antiseptics or antibiotics, new hub models, and antibiotic lock solutions, are briefly described (Table 1).

For short-term CVCs (i.e. those in place <10 days), which are most commonly colonized by cutaneous organisms along the external surface of the catheter, the most important preventive systems are those that decrease the extraluminal contamination. In contrast, with long-term CVCs (i.e. those in place >10 days), in which endoluminal spread from the hub appears to be the primary mechanism of infection, technologies that reduce endoluminal colonization in addition to extraluminal invasion of the catheter should provide additional protection against CRBSI.

This report is based on a literature review of published articles in the prevention of intravascular catheter-related infections. The review was conducted by searching the Medline database of the National Library of Medicine, Bethesda, MD, USA using the following key terms: catheter-related infections, catheter-related bloodstream infections, intravascular devices, central venous catheter, prevention, infection control practices, guidelines, and new technologies. The bibliographies of selected articles were also reviewed for pertinent studies.

Antimicrobial lock is a novel technique in which an antimicrobial solution, often consisting of an anticoagulant along with an antibiotic agent, is instilled into the lumen of the catheter and allowed to remain for a defined period, usually 6–12 hours, after which it is removed. Antimicrobial lock solutions have shown to be mostly effective for the prevention of infections associated with long-term CVCs 4142 but they could also be useful in short-term catheters 43.

Various antimicrobial agents have been shown to be efficacious in reducing the risk for infection, including vancomycin–heparin and vancomycin–ciprofloxacin–heparin solutions 4244. Because the use of vancomycin is an independent risk factor for the acquisition of vancomycin-resistant enterococci 45, this practice is not recommended for routine use 1. However, in individual cases in which a patient requires indefinite vascular access but continues to experience CRBSIs despite rigorous observance of infection control measures, the use of vancomycin lock solution to preserve vascular access should be considered. A novel lock solution consisting of minocycline and EDTA (M-EDTA) has also been shown to have antimicrobial activity against the most common organisms associated with CRBSI, including Gram-positive and Gram-negative bacteria and Candida albicans, resulting in prevention of infection 46. In a prospective cohort study, M-EDTA proved to be efficacious in preventing port-related infections without causing any adverse events 47. However, randomized clinical trials are needed to test further the ability of M-EDTA to prevent long-term CVC infections.

Prophylactic use of anticoagulant agents, including heparin or warfarin, reduced the incidence of catheter thrombosis 204142. Because thrombi could serve as a nidus for microbial colonization of CVCs 4849, the use of anticoagulants may have a role in the prevention of CRBSI. For example, in a double-blind randomized controlled study conducted in a pediatric intensive care unit, heparin bonding was associated with a significant reduction in the incidence of infection (4% and 33% in heparin-bonded and non-heparin-bonded CVCs, respectively) 50. Furthermore, in a meta-analysis evaluating benefit of heparin prophylaxis (doses of 3 U/ml total parenteral nutrition, 5000 U every 6 or 12 hours, or 2500 U of subcutaneous low-molecular-weight heparin every day) in patients with CVCs, the risk for catheter-related central venous thrombosis was reduced with the use of prophylactic heparin 51. The meta-analysis also found a significantly decreased risk for bacterial colonization of the catheter and an associated reduction in CRBSI with use of heparin; however, studies included used variable definitions of catheter-related infections and the findings require confirmation by trials adhering to current, stricter definitions.

A better understanding of the pathogenesis of CVC-related infections should lead to the development of more effective preventive strategies, including antiseptics with greater and more prolonged antimicrobial activity, and new materials that make CVCs intrinsically resistant to microbial colonization and that do not promote antimicrobial resistance. Because of its critical role in the infection process, bacterial adherence represents a potential target for the development of new preventive strategies, and agents that can block the process of adherence, such as specific bacterial surface adhesin-blocking antibodies, may prove to be effective at preventing infections. In vitro studies have been conducted to assess the effectiveness of new polymer–antibiotic systems in inhibiting bacterial biofilm formation 52 and in reducing neutrophil activation after surface contact on different biomaterials, thus reducing the risk for biomaterial-mediated inflammatory reactions 53. Moreover, organisms such as staphylococci, Candida spp. and some others produce a microbial biofilm that helps them to survive on the surfaces of foreign bodies in the bloodstream. The development of biofilm involves intercellular signaling molecules that serve in a communication system termed quorum sensing. Quorum sensing enables population density control of gene expression 54. Molecules that inhibit quorum sensing signal generation among organisms could block microbial biofilm formation and prevent catheter colonization 55.

CRBSIs, as a consequence of the use of CVCs, are associated with significant morbidity, mortality and additional medical costs. Nevertheless, most CVC-related infections are preventable, and preventive strategies should aim at achieving maximal antiseptic barrier precautions during catheter insertion, catheter site maintenance, and hub handling. However, new technologies that have already been proven to be effective in clinical trials in preventing CVC infections, particularly those intended for short-term use, should be considered in clinical practice. Moreover, many of these new technologies have proven to be not only effective but also cost-effective.

None declared.

CRBSI = catheter-related bloodstream infection; C-SS = chlorhexidine and silver sulfadiazine; CVC = central venous catheter; M-EDTA = minocycline and EDTA.