Total parenteral nutrition (TPN) has been identified as a risk factor for catheter related blood stream infection (CRBSI).  Central venous access devices (CVAD) used to administer TPN provide a direct pathway for pathogens to enter the blood stream either from skin or hub migration.

TPN solutions are susceptible to microbial growth because of the necessary nutritional components they contain. Fat emulsions, amino acids, and dextrose support microbial growth.  Temperature, pH, and infusion time may contribute to bacterial and fungal proliferation.  Contamination during compounding is rare when hospital and home care facilities follow the American Society of Health-System Pharmacists guidelines for sterile admixing.  Microorganisms are usually introduced into the sterile system from manipulations by clinicians and caregivers during the administration process.

Intraluminal microbial biofilm begins to develop shortly after CVAD insertion, gradually forming a denser matrix over time.  Biofilm is a substance in which bacteria and fungi live and grow. Long term catheters may develop a fibrin sheath or tail at the distal catheter tip and daily infusion of TPN may contribute to development of central venous thrombosis.  These conditions involving clot create prime sites near or on the catheter surface for microbial seeding and eventual infection.  Many home TPN consumers also develop chronic urinary tract infections, or have ostomies and gastrostomy tubes which are potential CVAD contaminates.  Psychosocial issues such as, non-compliance, drug use, and depression have been shown to increase the home TPN consumer’s risk for infection.

Coagulase-negative staphylococcus can be attributed to approximately 60% of CRBSI in the home TPN population, followed by Klebsiella pneumoniea, staphylococcus aureus,  and enterococcus.  Candida parapsilosis, glabrata, and albicans are frequently cultured from long term central lines used for TPN.   Diligent hub care with alcohol and friction over 15-20 seconds with each flush or tubing hook up has been shown to kill these bacteria and fungi.  Also, use a new alcohol pad each time a surface is swabbed.