Validation of the Proposed Definition for Complicated Coagulase-negative Staphylococcal Bacteremia.

Background: A new definition for complicated coagulase-negative staphylococcal (CoNS) bacteremia was recently proposed. The aim of this study was to identify predictors of mortality in patients with CoNS bacteremia and evaluate the proposed definition of complicated bacteremia.

Methods: This retrospective study was conducted at the Lausanne University Hospital, Switzerland (2015-2023) and included adult patients with CoNS bacteremia.

Results: During the study period, 326 episodes of CoNS bacteremia were included, with 250 (77%) episodes involving Staphylococcus epidermidis. Most infections were catheter-related bacteremias (233 episodes; 68%). Based on the proposed definition, 195 (60%) episodes had complicated disease. The overall 30-day mortality was 9% (29 episodes). Infectious diseases (ID) consultation was provided within 48 hours from bacteremia onset in 285/326 (87%) episodes. Source control was deemed necessary in 275 (84%) episodes and was performed within 48 hours in 167/275 (61%) episodes. No difference on 30-day mortality was observed among complicated and uncomplicated disease (10% vs 7%; P = .327). The Cox multivariable regression model showed that a Charlson comorbidity index >4 (adjusted hazard ratio, 3.80; 95% confidence interval, 1.52-9.47) was associated with 30-day mortality, whereas ID consultation within 48 hours (0.22, 0.10-0.48) and performance of source control interventions within 48 hours (0.12, 0.03-0.50) were associated with improved outcome. Complicated disease was not associated with 30-day mortality (0.39, 0.10-1.46).

Conclusions: The proposed definition for complicated CoNS bacteremia failed to identify patients at higher risk for mortality in our cohort. Our findings highlight the importance of ID consultation in guiding antimicrobial treatment and recommending source control interventions for patients with CoNS bacteremia.