A prospective study of central venous hemodialysis catheter colonization and peripheral bacteremia

Background: Sepsis as a consequence of central venous hemodialysis catheter colonization is a major cause of morbidity in the hemodialysis population. We have previously shown that the majority of catheters become colonized a nd that this is associated with peripheral bacteremia. The time period over which this colonization occurs is unknown. Method: A prospective study of 31 central venous hemodialysis catheters was performed. Central venous bloo d cultures were taken from the catheter weekly after insertion. When the ce ntral cultures became positive, indicating catheter colonization, periphera l venous blood cultures were taken during dialysis to detect peripheral bac teremia. Results: Twenty-one catheters (68%) became colonized before their removal for reasons other than infection (mean time to colonization 27 days , range 5 - 115 days). Eleven patients (35%) developed peripheral bacteremi a with the same organisms (mean time from colonization to bacteremia 32 day s, range 5 -126 days). Bacteremia only occurred when blood drawn from the c atheter cultured more that 3000 colony forming units per ml. Conclusions: B acterial colonization of central venous catheters often leads to bacteremia . The time between insertion and colonization is very variable, but is univ ersally present after 16 weeks. The risk of subsequent bacteremia is relate d not only to time left in situ, but also the degree of colonization. Surve illance cultures would allow clinicians to detect colonization before bacte remia occurs and take preventative measures.