title: Staphylococcus aureus bacteremia in immunosuppressed patients: a multicenter, retrospective cohort study.
abstract: Staphylococcus aureus bacteremia (SAB) causes significant morbidity and mortality. We assessed the disease severity and clinical outcomes of SAB in patients with pre-existing 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-hospital mortality (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.
authors.affiliation: Department of Medicine, University of Toronto, Toronto, ON, Canada.
authors.forename: G
authors.initials: G
authors.lastname: Sasson
authors.affiliation: Department of Medicine, Queen's University, Kingston, ON, Canada.
authors.forename: A D
authors.initials: AD
authors.lastname: Bai
authors.affiliation: Department of Medicine, University of Toronto, Toronto, ON, Canada.|Division of Infectious Diseases, University of Toronto, Toronto, ON, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Showler
authors.affiliation: Sinai Health System, 600 University Ave, Rm #415, Toronto, ON, M5G 1X5, Canada.|Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Burry
authors.affiliation: Sinai Health System, 600 University Ave, Rm #415, Toronto, ON, M5G 1X5, Canada. marilyn.steinberg@sinaihealthsystem.ca.
authors.forename: M
authors.initials: M
authors.lastname: Steinberg
authors.affiliation: Division of Infectious Diseases, University of Toronto, Toronto, ON, Canada.|Lakeridge Health, Oshawa, ON, Canada.
authors.forename: D R
authors.initials: DR
authors.lastname: Ricciuto
authors.affiliation: Trillium Health Partners, Mississauga, ON, Canada.
authors.forename: T
authors.initials: T
authors.lastname: Fernandes
authors.affiliation: Trillium Health Partners, Mississauga, ON, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Chiu
authors.affiliation: North York General Hospital, Toronto, ON, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Raybardhan
authors.affiliation: Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Science
authors.affiliation: Department of Medicine, University of Toronto, Toronto, ON, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Fernando
authors.affiliation: Department of Medicine, University of Toronto, Toronto, ON, Canada. andrew.morris@sinaihealthsystem.ca.|Division of Infectious Diseases, University of Toronto, Toronto, ON, Canada. andrew.morris@sinaihealthsystem.ca.|Sinai Health System, 600 University Ave, Rm #415, Toronto, ON, M5G 1X5, Canada. andrew.morris@sinaihealthsystem.ca.|University Health Network, Toronto, ON, Canada. andrew.morris@sinaihealthsystem.ca.
authors.forename: A M
authors.initials: AM
authors.lastname: Morris
authors.affiliation: Department of Medicine, University of Toronto, Toronto, ON, Canada.|Sinai Health System, 600 University Ave, Rm #415, Toronto, ON, M5G 1X5, Canada.|University Health Network, Toronto, ON, Canada.|Institute for Clinical Evaluative Sciences, Toronto, ON, Canada.
authors.forename: C M
authors.initials: CM
authors.lastname: Bell
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000453:epidemiology* / Q000382:microbiology / Q000473:pathology; D002170:Canada / Q000453:epidemiology; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology / Q000473:pathology; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult