Central venous catheter-related infections in hematology and oncology

Catheter-related infections (CRI) cause considerable morbidity in hospitalized patients. The incidence does not seem to be higher in neutropenic patients than in nonneutropenic patients. Gram-positive bacteria (coagulase-negative staphylococci, Staphylococcus aureus) are the pathogens most frequently cultured, followed by Candida species. Positive blood cultures are the cornerstone in the diagnosis of CRIs, while local signs of infection are not necessarily present. Blood cultures should be taken from peripheral blood and from the venous catheter. A shorter time to positivity of catheter blood cultures as compared with peripheral blood cultures supports the diagnosis of a CRI. In many cases, a definite diagnosis requires catheter removal and microbiological analysis. The role plate method with semiquantitative cultures has been established as standard in most laboratories. Antimicrobial treatment of CRI should be directed by the in vitro susceptibility of the isolated pathogen. Primary removal of the catheter is mandatory in S. aureus and Candida infections, as well as in case of tunnel or pocket infections. Future studies will elucidate whether the rate of CRI in neutropenic patients may be reduced by catheters impregnated with antimicrobial agents.