Studies of
total parenteral nutrition-related
infection have incorrectly relied on positive results on culture of the
cannula tip to confirm the source. We undertook a prospective study of
total parenteral nutrition-related
infections in adult patients by obtaining blood from all
total parenteral nutrition lines for pour-plate culture twice weekly and culturing intravascular line segments by the technique of Maki. Twelve of 100 courses of
total parenteral nutrition (12 percent) in 69 patients resulted in
infections--five (5.0 percent) had
sepsis, and seven (7.0 percent) had local
infection. In five of these 12, pour-plate culture gave positive results (five of 38 pour plates) with counts of 8 colony-forming units per ml (cfu/ml) for Candida tropicalis, and 25 to more than 1,000 for bacterial isolates. In nine of 12, culture of the intravascular line segment gave positive results with more than 50 cfu/ml. Pathogens isolated from intravascular line segments included Staphylococcus epidermidis (three cases), Candida species (three cases), Staphylococcus aureus (two cases), Serratia marcescens (one case) and mixed bacterial pathogens (one case). In contrast, pour-plate culture gave positive results in only seven of 88 uninfected (control) courses (318 pour plates), and culture of intravascular line segments gave positive results in two of 65 uninfected courses (p less than 0.001). No differences existed among patients with and without
infection with regard to age, underlying disease, surgery, systemic
antibiotic usage, or the presence of other
infections. The duration of
total parenteral nutrition was longer in courses without
infection than in courses with
infection (14.7 +/- 9.4 days versus 11.0 +/- 4.0 days; p less than 0.02). In six of 12 courses with
infection, the line had been violated compared with 22 of 88 courses without
infection (p less than 0.001). T-connectors for the centra administration of
intralipid were associatd with
infection (p less than 0.02). The value of routine pour-plate culture was illustrated in three courses in which the positive pour-plate culture results antedated positive blood culture results or line removal.