Central venous catheter colonization with Staphylococcus aureus is not always an indication for antimicrobial therapy

Whether patients whose catheter tip grows Staphylococcus aureus but who have no concomitant bacteraemia should receive antimicrobials remains an unresolved issue. However, a proportion of patients with catheter tips colonized by S. aureus have no blood cultures taken because of low suspicion of sepsis and the meaning of this microbiological finding is unknown. We have analysed all catheter tips growing S. aureus during a 6-year period and have selected patients without blood cultures taken 7 days before or after central vascular catheter removal. Patient's evolution was classified into good and poor outcome. Poor outcome was defined as S. aureus infection within 3 months after catheter withdrawal or death in the same period with no obvious cause. Patients with good and poor outcomes were compared to assess whether antimicrobial therapy influenced evolution. Sixty-seven patients fulfilled our inclusion criteria and five (7.4%) had a poor outcome. The administration of early anti-staphylococcal therapy had no impact on the outcome of this population (p 0.99). The only factor independently associated with a poor outcome was the presence of clinical signs of sepsis when the catheter was removed (OR 20.8; 95% CI 2.0-206.1; p 0.009). Our data suggest that patients with central vascular catheter tips colonized with S. aureus should be closely monitored for signs and symptoms of ongoing infection, but if these are not present then antimicrobial therapy does not seem justified.