Diagnosis of Central Venous Catheter-Related Sepsis Using Differential Quantitative Blood Cultures

Lim, Woo Hyun; Shin, Jong Hee; Suh, Soon Pal; Ryang, Dong Wook

Abstract

BACKGROUND: When central venous catheter (CVC) related sepsis is suspected based on clinical symptoms, removal of catheter is both diagnostic and therapeutic, but this approach leads to wastage of many sterile lines. Therefore, a reliable method to diagnose or exclude CVC sepsis without catheter removal is desirable. We performed differential quantitative blood cultures for the diagnosis of CVC related sepsis, in catheterized patients who had previous positive blood cultures.
METHODS
Differential quantitative blood cultures were performed by collecting the blood specimens simultaneously via catheter and peripheral vein in 1.5 mL Isolator tubes (Wampole, USA). Sixty-three samples from 61 catheterized patients were taken and the colony counts from catheter blood samples were compared with those from peripheral samples.
RESULTS
In 17 samples (27%), the colony counts from catheter blood samples were 5-fold higher than those from peripheral samples (the C/P ratio, > OR =5), suggesting CVC related sepsis; in 7 samples the C/P ratio was below 5, suggesting that sepsis was not CVC related. Of 35 samples (56%) in which no organisms were cultured, 2 samples were diagnosed as CVC related sepsis by the catheter tip culture. In 19 cases with proven CVC related sepsis, Candida spp. (n=8) and Gram-negative rods (n=7) were the predominant causative organisms and 16 cases (84%) were improved after catheter removal.
CONCLUSIONS
This data show that quantitative blood culture method using Isolator may be very useful for diagnosing CVC related sepsis, especially in patients with positive blood cultures.