The potential use of blood culture systems for diagnosing intravascular catheter-related infections.

Background: A microbiological method for the quantitative analysis of intravascular catheter infections using the BacT/Alert and Bactec blood culture systems is presented.

Methods: The number of bacteria present on an intravascular catheter surface was determined by the time to detection of positivity in a blood culture bottle inoculated with a suspension of bacteria shaken from the catheter surface.

Results: The new method was used to examine 573 intravascular catheters. In 94.6% of the cases, the results of microbiological analysis of catheters were in accordance with the patient's clinical condition. Twenty-eight (4.8%) cases were false positive and ten (1.7%) were false negative. Based on clinical signs, 49 cases of catheter-related sepsis were diagnosed. In 39 (79.6%) of those, the microbiological analysis of intravascular catheters was positive (kappa = 0.69). The most frequently detected pathogens were coagulase-negative staphylococci.

Conclusions: In comparison to the current procedures, the new method is easier, faster, and capable of detecting the most common causative agents of catheter-related infections.