Staphylococcus epidermidis bloodstream infections are a cause of septic shock in intensive care unit patients

Abstract

Objectives: Staphylococcus epidermidis (SE) is a supposedly low-virulence agent, which may cause proven bloodstream infections (BSIs), with little-known consequences on intensive care unit (ICU) patients. We aimed at studying ICU patients diagnosed with BSIs caused by SE (SE-BSIs).

Methods: We constituted a retrospective cohort in two medical ICUs. SE-BSIs were defined by two or more independent SE-positive blood cultures of the same strain, within 48 hours, without concurrent infection.

Results: We included 59 patients; 58% were men (n = 34), with median age of 67 (interquartile range 60-74) years and a simplified acute physiology score II of 59 (36-74) points, and 56% were immunocompromised (n = 33). Among the 37 (63%) patients requiring norepinephrine initiation or increase at the onset of SE-BSI versus patients not requiring vasopressors (37%; n = 22), concomitant arterial lactate levels reached 2.8 (1.9-5.8) versus 1.5 (1.3-2.2) mmol/l (P <0.01), whereas the mean blood pressure was 49 (42-54) versus 61 (56-65) mm Hg (P = 0.01) and the mortality was 46% (n = 17) vs 14% (n = 3) at day 28 (P = 0.01), respectively. Regarding antibiotics, the susceptibility rates toward linezolid and vancomycin were 71% (n = 41/58) and 100% (n = 54/54), respectively. At the time of SE-BSI, all but one patient had a central venous access device.

Conclusion: This work highlights SE-BSIs as a cause of septic shock, mostly in immunocompromised ICU patients, with increasing concerns about resistance to antibiotics and central line management.

Keywords: Critical care; Immunocompromised host; Lymphopenia; Neoplasms; Septic shock; Staphylococcus epidermidis.