NEW YORK (Reuters Health) - Hemodialysis patients with tunneled catheters are known to be at increased risk of Staphylococcus aureus bacteremia, but now new research suggests that aspirin therapy may help combat this infection.

The findings from laboratory experiments have indicated that aspirin has direct antistaphylococcal effects. On this basis, Dr. Martin Sedlacek, from Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire, and colleagues hypothesized that long-term aspirin therapy might reduce the risk of S. aureus bacteremia in at-risk dialysis patients.

The new study, which appears in the American Journal of Kidney Diseases for March, involved analysis of 4722 blood cultures that were obtained from 872 patients over more than 476 patient-catheter-years. Patient on aspirin therapy received 81 mg or 325 mg each day.

The rate of S. aureus bacteremia in aspirin-treated patients was 0.17 events/patient-catheter-year, significantly lower than the 0.34 events/patient-catheter-year seen in the non-aspirin-treated patients (p = 0.003). However, aspirin therapy seemed to have no effect on the occurrence of infections by other microbes.

The antistaphylococcal benefit of aspirin therapy was dose-dependent and primarily seen with the 325-mg dose, the authors note.

On final analysis, aspirin use lowered the risk of S. aureus bacteremia by 54% (p = 0.002). Aspirin therapy was also linked to a reduced risk of a first episode of methicillin-resistant S. aureus bacteremia and with a lower risk of distant complications from the first episode of catheter-related S. aureus bacteremia.

"Our data constitute one of the largest studies of dialysis catheter-associated bacteremia," the researchers note.

"Our findings strongly support the need for a prospective analysis of aspirin treatment in hemodialysis patients and other populations at increased risk of staphylococcemia."