Epidemiology of bloodstream infection associated with parenteral nutrition.

EPIDEMIOLOGY: Catheter-related bloodstream infections (CR-BSIs) occur in 1.3% to 26.2% of patients with central venous catheters used to administer parenteral nutrition (PN). Because of their nutritional components, PN solutions can support microbial growth. Contamination during preparation and handling is rare in hospitals and home-infusion pharmacies but may be difficult to control in a home setting. The risk of infection is increased in hospitalized patients because of malnutrition-associated immunosuppression, hyperglycemia exacerbated by dextrose infusion, microbial colonization/contamination of catheter hubs and the skin surrounding insertion site, and poor nursing care. During long-term catheter use for PN, an intraluminal biofilm, catheter-tip fibrin sheath or tail, or central venous thrombosis creates sites for microbial seeding and infection. Chronic conditions and psychosocial issues also increase the risk of infection. In hospitalized patients with BSIs, the most common organisms are coagulase-negative staphylococcus, Staphylococcus aureus, Enterococcus, Candida spp, Klebsiella pneumoniae, and Pseudomonas aeruginosa. In the long-term PN population, approximately 60% of CR-BSIs are caused by coagulase-negative Staphylococcus. TREATMENT: The best plan of care for a suspected or known infected catheter in a hospitalized patient is to reinsert a new central line after 48 hours of antibiotic treatment and negative blood cultures. In patients who receive long-term PN, hospitalization increases the risk of a nosocomial infection because the catheter can be contaminated by staff. A patient with fungemia must always be admitted and catheter removed. With gram-positive and gram-negative organisms, the catheter may not need to be removed. In most patients receiving PN at home, removing a long-term venous-access device is challenging. Peripheral vein access or peripherally inserted central catheters are needed until a new permanent device can be inserted after negative blood cultures are obtained. Evaluation of remote site infection also is necessary. Strategies to reduce or prevent infection include catheter lock therapy, daily evaluation of continued need for PN, enteral rather than PN support, and avoiding overfeeding. More studies are needed to demonstrate conclusively the benefits of immunonutrition, such as the use of omega-3 or glutamine supplements to reduce CR-BSIs in patients receiving PN.