The use of continuous monitoring blood culture systems in the diagnosis of catheter related sepsis.

AIM To assess whether the information provided by automated continuous monitoring blood culture systems could aid in the diagnosis of catheter related sepsis. METHODS Serial dilutions of a strain of coagulase negative staphylococcus were inoculated into the BacT/Alert blood culture system. Blood culture results for seven patients with possible catheter related sepsis from coagulase negative staphylococci were reviewed. RESULTS Time to positivity and length of lag period were strongly related to the concentration of bacteria inoculated (average decrease of 1.5 hours to positivity for each 10-fold increase in concentration). Time to positivity and length of lag period were significantly shorter for central line blood cultures than for those taken from peripheral sites. CONCLUSIONS Using data already measured by continuous monitoring blood culture systems may provide a simple alternative to quantitative blood cultures for the diagnosis of catheter related sepsis.