Research Articles from the SHS-UHN ASP (Category)

Staphylococcus aureus bacteremia in immunosuppressed patients: a multicenter, retrospective cohort study

G Sasson
A Bai
A Showler
L Burry
M Steinberg
D. Ricciuto
T Fernandes
A Chiu
S Raybardhan
M Science
E Fernando
A Morris
C Bell


Staphylococcus aureus bacteremia (SAB) causes significant morbidity and mortality.  We assessed the disease severity and clinical outcomes of SAB in patients with preexisting immunosuppression, compared with immunocompetent patients.  A retrospective cohort investigation studied consecutive patients with SAB hospitalized across six hospitals in Toronto, Canada from 2007 to 2010.  Patients were divided into immunosuppressed (IS) and immunocompetent (IC) cohorts; the IS cohort was subdivided into presence of one and two or more immunosuppressive conditions.  Clinical parameters were compared between cohorts and between IS subgroups.  A competing risk model compared in-hospital mortality and time to discharge.  A total of 907 patients were included, 716 (79%) were IC and 191 (21%) were IS.  Within the IS cohort, 111 (58%) had one immunosuppressive condition and 80 (42%) had two or more conditions.  The overall in-hospital mortality was 29%, with no differences between groups (IS 32%, IC 28%, p = 0.4211).  There were no differences in in-hospitalmortality (sub-distribution hazard ratio [sHR] 1.17, 95% confidence interval [CI] 0.88–1.56, p = 0.2827) or time to discharge (sHR 0.94, 95% CI 0.78–1.15, p = 0.5570).  Independent mortality predictors for both cohorts included hypotension at 72 h (IS:  p < 0.0001, IC: p < 0.0001) and early embolic stroke (IS:  p < 0.0001, IC: p = 0.0272).  Congestive heart failure was a mortality predictor in the IS cohort (p = 0.0089).  Fever within 24 h (p = 0.0092) and early skin and soft tissue infections (p < 0.0001) were survival predictors in the IS cohort.  SAB causes significant mortality regardless of pre-existing immune status, but immunosuppressed patients do not have an elevated risk of mortality relative to immunocompetent patients.
Sasson G, Bai AD, Showler A, Burry L,  Steinberg M, Ricciuto DR, Fernandes T, Chiu A, Raybardhan S, Science M, Fernando E, Morris AM, Bell CM. Staphylococcus aureus bacteremia in immunosuppressed patients: a multicenter, retrospective cohort study. Eur J Clin Microbiol Infect Dis. 2017; DOI 10.1007/s10096-017-2914-y