Poor Value of Surveillance Cultures for Prediction of Septicaemia Caused by Coagulase-negative Staphylococci in Patients Undergoing Haemodialysis with Central Venous Catheters

Abstract

Surveillance cultures for the demonstration of coagulase-negative staphylococci in patients on catheter haemodialysis were performed in an attempt to predict dialysis catheter-related septicaemia. In all, 43 patients with 67 haemodialysis catheters were followed for a 1-y period. Once a week, swab specimens were obtained from the skin at the insertion site and the hub, and blood cultures were obtained from the catheter. Among coagulase-negative staphylococci, S. epidermidis was the most frequently (80%) isolated species, and two biotypes accounted for 55.7% of the 41 biotypes isolated. 11 septicaemia cases due to coagulase-negative staphylococci occurred, all caused by S. epidermidis, and the incidence of S. epidermidis septicaemia was 21% among patients and 16% among catheter periods. S. epidermidis septicaemia occurred in 17%, 31% and 33% of all catheter periods in which S. epidermidis was cultured from the skin, hub and catheter blood, respectively. In two-thirds of all catheter periods, S. epidermidis was cultured from catheter blood despite lack of clinical signs of septicaemia. In conclusion, cultures from the skin, hub or catheter blood are not useful for prediction of dialysis catheter-related septicaemia due to coagulase-negative staphylococci. When septicaemia is suspected, peripheral blood cultures are mandatory to reach a correct diagnosis and aetiology.