POSITIVE INTRAVENOUS LINE TIP CULTURES AS PREDICTORS OF BACTEREMIA

Intravenous line tip cultures provide valuable information when taken in conjunction with blood culture, but in practice are often performed in isolation. This retrospective study has evaluated: (1) the frequen cy of isolated line tip culture; and (2) whether the species of microo rganism isolated from line tip culture, using the Maki semi-quantitati ve culture method, is predictive of bacteraemia. Of 2753 line tip cult ure episodes in 1659 patients between May 1993 and August 1995, 2230 w ere performed in isolation (81%). Evaluation of 792 positive line tip culture episodes in 654 patients where blood cultures were performed i n the period from 48 h before, to 24 h after tip culture, identified 8 25 line tip isolates. Of these, 194 were associated with a blood cultu re positive for the same species. The rate of positive blood culture, according to species, ranged from 10-72%. The highest rate was seen fo r methicillin-susceptible Staphylococcus aureus where 70 of 97 line ti p episodes (72%) were associated with positive blood culture. This com pared with a rate of 17% for coagulase-negative staphylococci (P<0.000 1). Patients with line tip cultures positive for S. aureus should be c onsidered to be at high risk of bacteraemia.