Coagulase-negative staphylococcal bacteremia: risk factors for mortality and impact of initial appropriate antimicrobial therapy on outcome

It is uncertain whether an initial inappropriate empirical antibiotic treatment of coagulase-negative staphylococci (CoNS) bacteremia adversely affects the outcome. A retrospective cohort study of CoNS bacteremia was performed at the Dongguk University Ilsan Hospital during a 3-year period. During the study period, 109 patients with CoNS bacteremia were enrolled. The median age of the patients was 72 years and most (96 %, 105/109) had one or more comorbid diseases. Among the participants, 29 % (32/109) received an appropriate empirical antimicrobial therapy. The 30-day mortality was 24 % (26/109) and CoNS bacteremia-related mortality was 14 % (15/109). There was no difference in the CoNS bacteremia-related mortality between the group with an inappropriate empirical treatment (13 %, 10/77) and that with an appropriate treatment (16 %, 5/32) (p = 0.46). In the multivariate analysis using the Cox regression analysis method, Pitt bacteremia scores [hazard ratio (HR) 1.48; 95 % confidence interval (CI) 1.09–2.01; p = 0.01] and retention of eradicable focus (HR 5.0; 95 % CI 1.39–17.9; p = 0.01) were found to be associated with CoNS bacteremia-related mortality. The results suggest that inappropriate empirical therapy might not necessarily be associated with the 30-day mortality or CoNS bacteremia-related mortality. Conversely, Pitt bacteremia scores and retention of eradicable focus were associated with poor outcomes.