Staphylococcus lugdunensis bacteremia: clinical implications of single set positive blood cultures.

Staphylococcus lugdunensis is exceptionally virulent among the coagulase-negative Staphylococcus species, but the clinical significance of single-positive bacteremia of S. lugdunensis remains uncertain. We investigated S. lugdunensis bacteremia cases over 10 years. Of the 49 cases included, 12 had multiple-positive blood cultures and 37 had single-positive blood cultures. Antimicrobial therapy was given to over 80% of both groups, whereas the duration of therapy was significantly longer in the multiple-positive group. The overall 30-day and 90-day mortality rates were 13.3% and 18.2%, and 36.7% and 18.2% for single and multiple-positive patients, respectively. Five single-positive patients without therapy did not have severe infection, presumed source of infection, or culture positivity within 20 hours, but all defervesced within 2 days and were alive at 30 days. While the clinical spectrum of single-positive S. lugdunensis bacteremia is broad, antimicrobial therapy may be withheld without adverse clinical consequences in a subset of low-risk patients.