Hub colonization as the initial step in an outbreak of catheter-related sepsis due to coagulase negative staphylococci during parenteral nutrition.

A prospective study was carried out to determine the pathogenesis of coagulase negative staphylococci catheter-related sepsis during parenteral nutrition. Forty-three catheters were cultured by semiquantitative and quantitative methods. The skin around the puncture site was cultured at the time of catheter removal and three segments of the catheter were cultured apart: the hub, the proximal subcutaneous segment, and the tip. Skin cultures were negative (89%) or yielded different coagulase negative staphylococci from those recovered in catheter and/or blood. Seventeen catheters were the source of sepsis. In 15 cases an infected hub was associated with an infected tip. In two cases the hub was negative (one sepsis due to mixture contamination and the other due to hematogenous seeding of the catheter tip). Sixteen cases of sepsis were due to coagulase negative staphylococci. Staphylococcus epidermidis has been the species most commonly isolated, followed by Staphylococcus haemolyticus, Staphylococcus saprophyticus, and Staphylococcus hominis. In our patients most catheter sepsis have their origin in an infected hub and are not due to migration of skin bacteria along catheter subcutaneous tunnel.